Motivators and barriers to research participation for individuals with cerebral palsy and their families.

OBJECTIVE(S): Our objective was to investigate the motivators and barriers associated with the individual or family decision to participate in cerebral palsy research. Based on this information, we offer suggestions to increase the likelihood of participation in future CP studies.
METHODS: A digital survey was administered to stakeholders affected by cerebral palsy across the US. Our analysis focused on variables related to personal interests, travel, and study-specific elements. Statistical tests investigated the effects of responder type, cerebral palsy type, and Gross Motor Function Classification System level on travel and study-specific element variables. Recommendations were informed by responses reflecting the majority of respondents.
RESULTS: Based on 233 responses, we found that respondents highly valued research participation (on average 88.2/100) and compensation (on average 62.3/100). Motivators included the potential for direct benefit (62.2%) and helping others (53.4%). The primary barriers to participation were schedule limitations (48.9%) and travel logistics (32.6%). Schedule limitations were especially pertinent to caregivers, while individuals with more severe cerebral palsy diagnoses reported the necessity of additional items to comfortably travel.
CONCLUSIONS: Overall, we encourage the involvement of stakeholders affected by cerebral palsy in the research process. Researchers should consider offering flexible study times, accommodating locations, and compensation for time and travel expenses. We recommend a minimum compensation of $15/hour and a maximum time commitment of 4 hours/day to respect participants' time and increase likelihood of research participation. Future studies should track how attitudes toward research change with time and experience.

Introduction

Cerebral palsy (CP) is a broad pediatric-onset diagnosis caused by a non-progressive injury to the developing brain [1]. The etiology of CP is also extremely heterogeneous, often resulting from brain injuries that occur during the early developmental period [2-5]. Although CP is considered a pediatric-onset disorder, the associated physical and behavioral presentations are present across the lifespan and may fluctuate in severity over time. As there is currently no cure for CP, research efforts are critical for advancing our understanding of the pathophysiology and most efficacious treatments. However, the diversity of this population poses a significant recruitment challenge to researchers [6]. Limited funding for CP research also puts an added burden on researchers to be efficient with study-specific elements and recruitment, especially in the United States [7]. In an attempt to address this, previous studies have surveyed individuals with CP to identify priority research areas [8-10]. Research registries have also been established to facilitate collaboration among US institutions and to improve communication between researchers and individuals with CP [11, 12]. Despite these efforts, the success of CP research is dependent on the desire of individuals to participate and their ability to reasonably access the study within the limitations of their environment.

A previous study investigated the barriers to intervention-based CP research and recommended the involvement of patient populations and their families in the study development pipeline to improve recruitment [6], an approach towards community-based participatory research. However, the study did not consider facilitators to research and only evaluated a small subset of the population interested in home-based training programs. Therefore, our objective was to sample a larger and more heterogeneous cohort of stakeholders and investigate the motivators and barriers associated with the decision to participate in CP research. We aimed to inform researchers of specific stakeholder perspectives by understanding whether factors such as Gross Motor Function Classification System (GMFCS) level, CP type, or age contribute to the decision to participate. Based on a nationwide survey, we provide recommendations for investigators to increase likelihood of recruitment and participation in future CP research.

Methods

I. Recruitment

The survey, including informed consent, was created and administered using the Research Electronic Data Capture (REDCap) platform. It was approved by the Northwestern University Institutional Review Board and remained open between May 6th and July 7th, 2020. Respondents were eligible to voluntarily participate if they resided in the United States and were either 1) caregivers of minors (under 18 years of age) with a diagnosis of CP or 2) adults with a diagnosis of CP. The survey link was shared via several platforms, including the Cerebral Palsy Research Registry [11], ResearchMatch.org, department social media accounts, and emails to previous research participants.

II. Experimental protocol: Qualitative survey

The digital open survey was designed to collect data about motivators and barriers of participation in CP research. The study objectives and survey questions were originally conceptualized from organic discussions among our research team. During survey development, we sought feedback from six caregivers of minors with CP and adults with CP to gather their opinions on the clarity of questions, the completeness of content, and the importance of the survey goals. The online survey [13] contained optional questions in six different categories: demographics, personal interests, travel needs & preferences, study-specific elements, past research experience, and impact of COVID-19. The present analysis focused on the first four categories to summarize attitudes towards general CP research. Details of the survey development are described in further detail by Joshi et al. [14].

III. Survey categories

Demographics

We collected a number of variables to describe features of the respondents, listed in Table 1. In addition to CP type and GMFCS level, we asked about elements such as the time it takes for respondents to get to medical appointments and information about current and previous medical treatments common to study inclusion or exclusion criteria.

Table 1

Participant demographics.

Characteristic	Respondent
	All (n = 233)		Adult with CP (n = 92)		Parent of minor with CP* (n = 141)
Sex assigned at birth
Male	112	48.1%	31	13.3%	81	34.8%
Female	120	51.5%	61	26.2%	59	25.3%
Not Reported	1	0.43%	0	0.00%	1	0.43%
Ethnicity
Hispanic or Latino	23	9.87%	7	3.00%	16	6.87%
Not Hispanic or Latino	204	87.6%	81	34.8%	123	52.8%
Not Reported	6	2.58%	4	1.72%	2	0.86%
Race
American Indian or Alaskan Native	2	0.86%	1	0.43%	1	0.43%
Asian	9	3.86%	3	1.29%	6	2.58%
Black or African American	24	10.3%	10	4.29%	14	6.01%
Native Hawaiian or Other Pacific Islander	1	0.43%	0	0.00%	1	0.43%
White	175	75.6%	68	29.2%	107	45.9%
Two or More Races	6	2.58%	4	1.72%	2	0.86%
Not Reported	16	6.87%	6	2.58%	10	4.29%
Gross Motor Function Classification System
Level I	60	25.8%	15	6.43%	45	19.3%
Level II	65	27.9%	33	14.2%	32	13.7%
Level III	33	14.2%	23	9.87%	10	4.29%
Level IV	37	15.9%	16	6.87%	21	9.01%
Level V	35	15.0%	4	1.72%	31	13.3%
Not Reported	3	1.29%	1	0.43%	2	0.86%
Cerebral Palsy motor topography
Hemiplegia	72	30.9%	18	7.72%	54	23.2%
Diplegia	60	25.8%	37	15.9%	23	9.87%
Quadriplegia	76	32.6%	24	10.3%	52	22.3%
Other	19	8.15%	10	4.29%	9	3.86%
Not Reported	6	2.58%	3	1.29%	3	1.29%
Previous research experience
Yes	101	43.3%	40	17.3%	61	26.2%
No	118	50.6%	48	20.6%	70	30.0%
Not Reported	14	6.01%	4	1.72%	10	4.29%
Proximity to medical appointments
Less than 30 minutes	58	24.9%	24	10.3%	34	14.6%
30 minutes to 1 hour	108	46.4%	45	19.3%	63	27.0%
More than 1 hour	55	23.6%	19	8.15%	36	15.5%
Not Reported	12	5.15%	8	3,43%	4	1.72%
Medical Treatments Received	Body Area
	Arms		Legs		Spine/Trunk
Bony surgery	4	1.72%	57	24.5%	11	4.72%
Soft tissue surgery	13	5.58%	109	46.8%	1	0.43%
Neural surgery	1	0.43%	6	2.58%	18	7.73%
Botox or other injections	39	16.7%	72	30.9%	6	2.58%
Non-injectable spasticity medication	35	15.0%	59	25.3%	31	13.3%
Physical or occupational therapy (current)	124	53.2%	153	65.7%	81	34.8%
Intensive therapy programs/camps (previous)	42	18.0%	39	16.7%	20	8.58%

*these demographics refer to the minor with cerebral palsy.

Personal interests

All subsequent variable names are italicized in text and described in Table 2. Personal interest factors were considered intrinsic to the respondent. Respondents were asked about their perception of research importance, how highly they value research participation, and compensation importance, all using a visual analog scale of 0–100 to easily quantify these subjective opinions. Open-ended questions in the survey requested comment on personal goals, motivators, and barriers for participation in CP research. To gauge specific research interests, respondents were asked what study types and body functions were of high interest to them.

Table 2

Summary metrics and statistical test results.

Variable	N	Summary Metrics Median (IQR)	Statistical Test	p-values
				GMFCS Level	CP Type	Responder Type
		Mean (SD)
Personal Interest
Research importance: Importance of CP research (0–100)	229	99 (9)
		93.8 (9.84)
Value research participation: Value of participation in CP research (0–100)	221	97 (18)
		88.2 (17.7)
Compensation importance: Importance of compensation for study participation (0–100)	203	64 (29)
		62.3 (25.7)
Study types: Study types most likely to contact a researcher to learn more about	228	See Results: Personal Interests
Body functions: Area of research focus most interested in participating or hearing more about	233	See Fig 2A
Travel Needs & Preferences
Childcare: Whether additional childcare is needed to participate	221	Yes: 75	Chi-square	p = 0.37	p = 0.08	p<0.001
		No: 146
Time off work: Whether time off work is needed to participate	220	Yes: 138	Chi-square	p = 0.18	p = 0.39	p = 0.31
		No: 82
Additional travel needs: What other things need to be considered to travel to a research study	174	See Fig 2B
Time			Chi-square	p = 0.02	p = 0.003	p = 0.91
Breathing			Chi-square	p = 0.002	p = 0.43	p = 0.70
Transition			Chi-square	p = 0.02	p = 0.25	p = 0.009
Seizure			Chi-square	p = 0.001	p = 0.30	p = 0.002
Feeding			Chi-square	p<0.001	p<0.001	p<0.001
Snacks			Chi-square	p = 0.48	p = 0.13	p<0.001
Medications			Chi-square	p<0.001	p = 0.03	p = 0.88
Toileting			Chi-square	p<0.001	p<0.001	p<0.001
Transportation			Chi-square	p<0.001	p<0.001	p = 0.22
Other			Chi-square	p = 0.07	p = 0.61	p = 0.22
Transportation: Preferred transportation method	220	See Fig 2C
Drive self			Chi-square	p = 0.01	p = 0.002	p<0.001
Family member drives			Chi-square	p = 0.97	p = 0.46	p = 0.06
Public transit			Chi-square	p = 0.02	p = 0.09	p<0.001
Ride service			Chi-square	p = 0.17	p = 0.34	p<0.001
Other			Chi-square	p = 0.03	p = 0.06	p = 0.001
Travel time for indirect benefit study: Maximum time willing to travel from home for study without the potential for direct benefit (0.5-more than 2 hrs)	219	4 (3)	Chi-square	p = 0.26	p = 0.44	p = 0.06
		3.53 (1.40)
Travel time for direct benefit study: Maximum time willing to travel from home for study with the potential for direct benefit (0.5-more than 2 hrs)	220	5 (2)	Chi-square	p = 0.37	p = 0.15	p = 0.12
		4.13 (1.19)
Overnight trip: Willingness to make overnight or extended trip for research study	221	Yes: 110	Chi-square	p = 0.98	p = 0.69	p = 0.75
		No: 19
		Maybe: 92
Travel reimbursement for a local study: Importance that cost of travel to local study is reimbursed (0–100)	203	50 (57)	Kruskal-Wallis	p = 0.14	p = 0.75	p = 0.007
		49.1 (32.8)
Travel reimbursement for a distant study: Importance that cost of travel to distant study is reimbursed (0–100)	205	78 (32)	Kruskal-Wallis	p = 0.54	p = 0.93	p = 0.69
		75.3 (24.3)
Study-specific Elements
Locations: Preferred study location	222	See Fig 2D
Current clinic			Chi-square	p = 0.68	p = 0.62	p = 0.03
New clinic			Chi-square	p = 0.29	p = 0.003	p = 0.94
Park			Chi-square	p<0.001	p = 0.01	p = 0.02
Lab			Chi-square	p = 0.58	p = 0.003	p = 0.58
School			Chi-square	p = 0.64	p = 0.19	p<0.001
Home			Chi-square	p = 0.12	p = 0.95	p = 0.18
Other			Chi-square	p = 0.76	p = 0.30	p = 0.29
Time of year: Times that would be considered for research participation	127	See Fig 2E
Weekends during school year			Chi-square	p = 0.11	p = 0.06	p = 0.68
Weekdays during school year			Chi-square	p = 0.06	p = 0.20	p = 0.05
Summer break			Chi-square	p = 0.68	p = 0.91	p<0.001
Spring break			Chi-square	p = 0.46	p = 0.61	p = 0.11
Winter break			Chi-square	p = 0.87	p = 0.41	p = 0.002
Non-attendance school days			Chi-square	p = 0.22	p = 0.15	p = 0.002
Maximum time commitment: Amount of time in one day that is reasonable to participate in a study (0.5–8 hrs)	220	4 (3)	Kruskal-Wallis	p = 0.11	p = 0.003	p = 0.002
		3.83 (1.16)
		See Fig 2F
Maximum study visits: Maximum number of visits for one study (1–5 visits)	219	5 (2)	Kruskal-Wallis	p = 0.62	p = 0.71	p = 0.21
		4.28 (1.10)
Longitudinal: Willingness to participate in longitudinal study (Yes or No)	220	Yes: 210	Chi-square	p = 0.19	p = 0.94	p = 0.19
		No: 10
Compensation amount: Appropriate amount of compensation ($/hr)	176	15 (10)	Kruskal-Wallis	p = 0.71	p = 0.68	p = 0.94
		16.7 (12.3)

Travel needs & preferences

Respondents reported whether additional arrangements for childcare would be required, whether time off work would be required, and what additional travel needs would be required when leaving the house. To understand travel preferences, respondents were asked about their typical mode of transportation to medical appointments. We also asked participants to identify their perceived maximum travel time for indirect benefit study, defined as a study that is seeking to understand more about CP, and maximum travel time for direct benefit study, defined as a study with the potential to offer a direct benefit to the participant. Participants were asked about their overall willingness to make an extended overnight trip for research participation. Finally, the importance of travel reimbursement for local study and travel reimbursement for distant study was evaluated, both on a scale from 0–100.

Study-specific elements

There were a number of variables related to explicit design of the study, which have the potential to be modified by the researcher. Respondents were asked about their most preferred study locations and their preferred time of year for study participation. Respondents’ desired compensation amount was evaluated per hour of study participation. Respondents were also asked about the maximum time commitment that was reasonable for one day of participation, the maximum study visits they would be willing to commit, and whether they would consider participating in a longitudinal study.

IV. Data and statistical analysis

IBM SPSS Statistics version 26 (IBM Corp., Armonk, NY, USA) was used to perform all analyses on the survey responses. Participants with missing data for a given question were excluded from analysis pertaining to that question. To summarize responses, descriptive analyses were first completed, with all percentages reported relative to the number of respondents for each question. We defined 50% as the threshold to describe the majority of survey respondents. Statistical analyses were only performed on travel and study-specific variables, as researchers can directly use this information to modify study methods during the developmental pipeline. Q-Q plots were created for quantitative variables to assess normality. Kruskal-Wallis tests, Chi-squared tests, or Kaplan-Meier survival analyses were performed on variables hypothesized to be dependent on three factors: Responder type (2 levels: adult, caregiver), CP type (4 levels: hemiplegia, diplegia, quadriplegia, other), and GMFCS level (5 levels: I, II, III, IV, V). A p-value < 0.05 was considered significant. Post hoc analyses were used to determine significant pairwise comparisons, where p-values were corrected for multiple comparisons using Bonferroni corrections. Further analyses were run to test specific hypotheses. For open-ended questions pertaining to personal interests, AH reviewed all responses, identified common themes, and categorized each response accordingly. Categorizations were reviewed and approved by KMZ and VG and summarized semi-quantitatively. For travel preferences, Wilcoxon signed-rank tests were run to determine differences between travel time for indirect benefit and travel time for direct benefit and between importance of travel reimbursement for local study and travel reimbursement for distant study.

Results

I. Demographics

In total, 255 individuals were consented and 233 (91.4% response rate) at least partially completed the survey. Respondent demographics are listed in Table 1. The survey population closely matches US census data in terms of sex, ethnicity, and race [14-16]. The majority of participants reported no previous research experience (53.9%), a proximity to medical appointments of 1 hour or less (75.1%), and previous or ongoing physical/occupational therapy treatment for their arms (53.2%) or legs (65.7%).

II. Personal interests

All subsequent variables and associated p-values are listed in Table 2. Respondents reported high mean scores for research importance (93.8/100), value research participation (88.2/100), and compensation importance (62.3/100). Open-ended questions revealed that the biggest personal motivators for CP research were personal benefit (62.2% of respondents) and helping others (53.4%) (Fig 1A), while the biggest personal barrier was schedule limitations (48.9%) (Fig 1B). With regard to research interests, the most popular study types were physical or occupational therapy treatments (90.8%), activity monitoring (79.1%), imaging of muscle/bone (72.4%), survey or online (71.5%), robotic games (68.9%), imaging of the brain (68.4%), and new treatments (64.9%). The most popular body functions of interest were the legs/feet (79.9%), muscles (79.5%), movement/fitness (79.0%), brain/nerves (76.0%), arms/hands (62.9%), and pain (50.7%) (Fig 2).

Fig 1

Percentage of respondents who indicated (A) motivators and (B) barriers for participating in research relating to the categories shown. Indented categories are subcategories of the parent category. (C) Representative quotes indicating goals for participating in research.

Fig 2

Body functions of research interest to respondents.

Each of these options was offered as a checkbox for respondents to indicate if they would be interested in participating in a study that focused on these body regions/functions. Percentages are out of n = 233 respondents.

III. Travel needs

Most respondents needed time off work (62.7%) but did not need additional arrangements for childcare to engage in research (66.1%). There was a significant main effect of responder type on the latter, where caregivers of minors with CP needed childcare more than adults with CP. When leaving their homes, the majority of respondents had additional travel needs such as time (59.2%), transportation items such as a wheelchair or stroller (58.0%), and snacks (52.9%) (Fig 3A).

Fig 3

(A) Summary of additional travel needs required to participate in CP research. The most prevalent categories were time, transportation, and snacks. (B) Summary of the most common transportation methods. Driving was the most cited mode of transportation. *6.8% of respondents selected other transportation modes.

Specific additional travel needs varied significantly based on GMFCS level, CP type, and responder type. All significant pairwise comparisons are reported in the (S1 Table). There was a significant main effect of GMFCS level on breathing items, seizure items, feeding items, medications, toileting items, and transportation items. In summary, individuals classified as GMFCS level V reported needing these items more to comfortably travel. There was a significant main effect of CP type on time, feeding items, toileting items, and transportation items. In general, individuals affected by quadriplegia reported needing these items more to comfortably travel. Finally, there was a significant main effect of responder type on transition, seizure items, feeding items, snacks, and toileting items. Adults with CP had more concerns about transition to a new environment than caregivers of minors with CP. However, caregivers needed seizure items, feeding items, snacks, and toileting items for their children more than adults with CP did for themselves.

IV. Travel preferences

The most common mode of transportation was by car, whether the individual drives (63.2%) or gets a ride from a family member (35.0%) (Fig 3B). There was a significant main effect of GMFCS level on transportation methods including drive self, public transit, and other, though there were no significant pairwise comparisons. There was a significant main effect of CP type on drive self, where respondents (both caregivers and adults with CP) affected by hemiplegia preferred to drive themselves more than those affected by diplegia or quadriplegia. There was a significant main effect of responder type on drive self, public transit, ride service, and other. Caregivers of minors with CP preferred to drive themselves more than adults with CP, whereas adults preferred public transit, ride services, or other methods of transportation.

The mean response for travel time for indirect benefit study was 3.53 hours, which was significantly lower (z = -6.857, p < 0.001) than the mean response for travel time for direct benefit study at 4.13 hours. Approximately half (49.8%) of respondents were willing to make an overnight trip for research participation. There was a significant main effect of responder type on the importance of travel reimbursement for a local study, where adults with CP thought reimbursement was more important than caregivers of minors with CP. The overall mean score for this variable (49.1/100) was significantly lower (z = -9.901, p < 0.001) than the mean score for the importance of travel reimbursement for a distant study (75.3/100).

A current clinic (88.7%), home (84.7%), lab (73.0%), and new clinic (59.9%) were the most preferred locations for research participation (Fig 4A). There was a significant main effect of GMFCS level on park, where individuals who are GMFCS level I were more likely to select this location than all other levels. There was a significant main effect of CP type on new clinic and lab, where individuals affected by hemiplegia were more likely to select these locations over those affected by quadriplegia. There was a significant main effect of responder type on current clinic, park, and school, where caregivers of minors with CP were more likely to select these locations over adults with CP.

Fig 4

(A) Summary of preferred locations for CP studies. *5.4% of respondents chose other locations. (B) Survival analysis for maximum time commitment by responder type. Less than 30% of caregivers and adults remain at 4 and 7 hours, respectively. (C) Summary of preferred time of year for participation by responder type.

The majority of respondents were flexible to participate in research at any time of year, except for parents on weekdays during the school year (Fig 4C). There was a significant main effect of responder type on weekdays, where adults reported more availability compared to caregivers. There was also a significant main effect of responder type for summer break, winter break, and other school holidays, where caregivers were more willing to engage in research during these times of year than adults. Respondents indicated a mean compensation amount of $16.69/hour for participation in research. The average maximum time commitment was 3.83 hours/day and the average maximum study visits was 4.28 visits. Survival analyses on maximum time commitment yielded significant main effects of CP type (log rank χ2(1) = 11.9, p = 0.001), with no significant pairwise comparisons, and responder type (log rank χ2(3) = 13.4, p = 0.004). Most notably, caregiver interest dropped from 54.1% to 24.1% at a maximum time commitment greater than 4 hours (Fig 4B). Finally, the vast majority of respondents were willing to participate in a longitudinal study (95.5%).

Discussion

The purpose of this study was to determine the motivators and barriers involved in the decision to participate in CP research studies. We administered a survey to gain more insight on stakeholder perspectives, including their personal interest in research, travel needs and preferences for study participation, and study-specific elements. These results can be extrapolated into recommendations for future CP research studies to maximize participant recruitment and expedite new knowledge about CP.

Our study is one of the first to identify the personal and practical factors that influence research participation. Respondents overwhelmingly supported research and valued their own participation in research, in a wide range of topics (Fig 2A). The research areas of interest identified by our survey respondents are largely consistent with previous reports of CP research priorities [8, 17]. Survey responses indicated that most individuals were motivated to participate by the potential for personal benefit and helping others. Where relevant, these two elements should be highlighted in recruitment materials and results should be disseminated to participants in a format that is best suited to their learning preferences (e.g. a copy of a manuscript or poster, a one-page summary, or a short video). Schedule limitations were the most prevalent barriers to research participation, especially as caregivers of minors with CP were likely to need additional childcare arrangements. Travel limitations were also a highly cited barrier to research participation. To minimize these barriers, researchers should offer flexible study times, particularly during the weekends and summer break, and/or utilize local study locations close to the home or clinics where participants are receiving care.

When scheduling participants with CP for a research study located outside of their home, travel needs for participants should be considered. To accommodate the additional time required for participants and/or their families to reach the study location, researchers should be flexible with appointment times. Indeed, utilizing flexible study protocols has previously been identified as a recommendation to improve recruitment in CP research [6]. Researchers should also consider having snacks available for participants, particularly for minors with CP. Unsurprisingly, participants classified as GMFCS level V or with a diagnosis of quadriplegia reported requiring more items in order to comfortably travel. Researchers working with these inclusion criteria might consider the home as a study location to mitigate the barrier of travel burden.

Respondents clearly noted the importance of compensation, as providing compensation to participants is consistent with appreciation of their time. In a previous study where caregivers of minors with CP were consulted on the design of randomized control trials, there was a strong preference for coverage of all treatment costs [18]. Caregivers noted that they may not be able to cover the costs themselves, the participants would be offering their time, and the study benefits were unknown [18]. From our survey responses, a minimum compensation of $15/hour and a maximum time commitment of 4 hours/day were interpreted to be respectful of the time and commitment to research participation.

In addition to financial incentives for participation, compensation for other expenses associated with travel should be considered. If a study session requires a longer duration, additional compensation can include paying for a meal. Because most respondents were willing to travel long distances for studies with and without potential for direct benefit, researchers should also consider offering travel reimbursement. This is especially important because travel limitations were a highly cited barrier to research participation. As the most preferred mode of transportation involves driving, suggestions for reimbursement include gas and parking. Flexibility around transport mode could also include fare coverage for adult participants who prefer public transit or ride services. For participants willing to make an overnight trip for a research study, researchers should consider compensating for lodging and overnight parking.

Our survey-based recommendations are centered around maximizing stakeholder participation in CP research studies. One limitation of our sample was that survey respondents were self-selected and may be biased towards research participation. Their responses may inflate measures of research importance and resource allocation (e.g. time and money), while underestimating obstacles to research participation. However, these individuals may also be more likely to respond to participant requests and therefore would be more representative of future study samples. Another limitation is that we allowed the terms “potential for direct benefit” and “indirect benefit” to be interpreted by the respondents. This does not address considerations such as the variability of perception of direct benefit [19] and therapeutic misconceptions [20]. Survey responses were self-reported at one time point. Future research should determine whether attitudes towards research shift over time or are dependent on the depth of previous research experience. Finally, researchers should be informed about and supported in the engagement of the community in research. This can span a spectrum of involvement, such as one-time consultations to provide feedback on study-specific elements, formation of Community Advisory Boards, or the inclusion of community stakeholders as project investigators. Our study including stakeholders during the design phase but would have required additional funding to adequately reimburse time and efforts for larger scale engagement. As a research team, we continue to look for ways to include family stakeholders in the research process as equal partners.

We assessed the motivators and barriers to research participation from the perspectives of caregivers of minors with CP and adults with CP. By identifying these stakeholder attitudes and utilizing the information to design study protocols, individuals with CP and their families become true partners in the research that aims to benefit people like them. Researchers can best accommodate the needs of participants with CP by opting for flexible study locations, scheduling, and compensation options. We recognize that this will not be feasible for all studies but encourage researchers to consider even the smallest gestures to reduce the burden of participation.

Significant pairwise comparisons after Bonferroni correction.

*Abbreviations: GMFCS = Gross Motor Function Classification System, di = diplegia, hemi = hemiplegia, quad = quadriplegia.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The manuscript is very good, the essence and concept are very clear and precise. A topic of this reserarch has importance in the motivations and increase number of respondents in the future research. It will be useful for future researchers in these fields.

Reviewer #2: Thank you for the opportunity to review this interesting article. It is a worthwhile contribution to the literature, to understand the facilitators and barriers to people with CP and their families participating in research.

Excellent introduction, sets up the study well.

Methods: Considering the topic, even though opinions were sought, it seems a shame there were no people with CP or family members involved as partners in this research? I see now that three family members seem to be acknowledged. Why are they not authors if they were involved in design and recruitment? Did you discuss interpretation of responses with them?

How were the categories and questions decided upon? Were families involved in this or did they just review for readability?

How was a scale of 1-100 decided upon?

The authors don't seem to have used a checklist such as CHERRIES https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1550605/

Results: A good number of responses (although response rate not reported). It would be helpful if % were written in Table 1, not just numbers. Motor type refers to spasticity/dyskinesis etc, but here it refers to topography.

Table 2 is difficult to interpret, especially what the three right hand columns are referring to. This needs further explanation. Is the main finding that they differ or don't differ? We are unable to tell from the table what the difference is (i.e. with GMFCS which GMFCS levels are associated with the variable of interest).

Discussion: There is limited literature supporting or critiquing the findings throughout the discussion. However, there are some very helpful findings from this survey, congratulations to the investigators.

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Reviewer #1: No

Reviewer #2: No

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14 Oct 2021

Reviewer(s)' Comments to Authors and Responses

(1) The manuscript is very good, the essence and concept are very clear and precise. A topic of this research has importance in the motivations and increases the number of respondents in the future research. It will be useful for future researchers in these fields.

Thank you for your comments and for taking the time to review the manuscript.

(2) Thank you for the opportunity to review this interesting article. It is a worthwhile contribution to the literature, to understand the facilitators and barriers to people with CP and their families participating in research.

Thank you for this encouraging comment.

(3) Excellent introduction, sets up the study well.

Thank you.

(4) Methods: Considering the topic, even though opinions were sought, it seems a shame there were no people with CP or family members involved as partners in this research? I see now that three family members seem to be acknowledged. Why are they not authors if they were involved in design and recruitment? Did you discuss interpretation of responses with them?

We appreciate this thoughtful comment. As we’ve now clarified in the acknowledgements section, the three individuals listed are research colleagues of the authors, and we have rectified the accidental omission those affected by CP in this section. Paragraph 2 of the methods section explains that we sought feedback from six individuals affected by CP on the clarity of survey questions, the completeness of content, and the importance of the survey goals. While these individuals were incredibly generous with their time, there were timing constraints associated with the pandemic that made a more substantial commitment difficult. Furthermore, we did not have funding to appropriately compensate them for larger contributions to the work. In relation to those affected by CP that participated in the survey, we plan to disseminate the results to all individuals who consented and selected the optional element to be informed.

(5) How were the categories and questions decided upon? Were families involved in this or did they just review for readability?

The original concept for this study was borne from organic discussions among our research team, so the objectives of the study were mostly established before engaging with stakeholders. However, we did make it clear that we were open to feedback at all levels and the stakeholders who responded focused on the way that questions were asked and how the survey was functioning. We clarified this in paragraph 2 of the methods section.

(6) How was a scale of 1-100 decided upon?

We used the REDCap digital version of the visual analog scale (VAS) for three personal interests variables (research importance, value research participation, compensation importance) to easily quantify subjective opinions, similar to the VAS used in pain literature. We’ve updated this in paragraph 4 of the methods section.

(7) The authors don't seem to have used a checklist such as CHERRIES https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1550605/

Thank you for bringing this to our attention. We completed the CHERRIES checklist and uploaded it as a separate document.

(8) Results: A good number of responses (although response rate not reported). It would be helpful if % were written in Table 1, not just numbers. Motor type refers to spasticity/dyskinesis etc., but here it refers to topography.

Overall response rate (91.4%) has been clarified in the first paragraph of the Results section. Table 1 has been modified to include the percentage of respondents in addition to the numbers for each demographic. Per the reviewer’s suggestion, “motor type” was changed to “motor topography” to reflect the information more appropriately in this category of Table 1.

(9) Table 2 is difficult to interpret, especially what the three right hand columns are referring to. This needs further explanation. Is the main finding that they differ or don't differ? We are unable to tell from the table what the difference is (i.e. with GMFCS which GMFCS levels are associated with the variable of interest).

Thank you for your remarks regarding the clarity of Table 2. We have removed the test statistics and degrees of freedom from each column to make the table more digestible, and we added a column to specify the statistical test used for each variable. Significant results in the three right-hand columns indicate differences between the particular respondent grouping (e.g. GMFCS levels, CP types) and the variable of interest. Please note that supplemental Table S1, which is referenced in the text (second paragraph of the ‘Travel Needs’ Results section), lists the significant pairwise comparisons. This table can be referenced for specific differences in GMFCS levels, etc. for each variable.

(10) Discussion: There is limited literature supporting or critiquing the findings throughout the discussion. However, there are some very helpful findings from this survey, congratulations to the investigators.

The reviewer raises a valid point; we are limited by the sparsity of existing literature on this topic. We have done our best to identify and discuss relevant previous work. This is all the more reason to do similar studies to gain a broader understanding of the needs and priorities of the cerebral palsy community.

Submitted filename: PLOS ONE Response to Reviewers.docx

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22 Nov 2021

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14 Dec 2021

Reviewer(s)' Comments to Authors and Responses

(1) Thank you for your responses to the reviewers. I have nothing further to add and look forward to seeing the paper in the literature. We all have a lot to improve on in this space.

We appreciate your comments and for taking the time to review the manuscript.

(2) Page 8, line 332-333 can you please add more clarity to this sentence: "In addition to direct payment, compensation for other costs associated with travel should be considered." There is an ethical difference between giving someone an incentive to sign up for a research study (e.g., $50 gift card), and reimbursing their expenses (e.g., travel, parking). What exactly do you mean by "direct payment"? In your paper, please be clear on the use of words that are meant to describe a recruitment incentive and expense compensation.

Thank you for your comments. We intended “direct payment” to be defined as the gift card or check that participants receive as incentive for study participation, but understand the concern that you’re sharing. Therefore, we have edited the sentence per your suggestion to: “In addition to financial incentives for participation, compensation for other expenses associated with travel should be considered” (pg. 18, lines 340-341 in the manuscript with tracked changes).

(3) First, I would like to thank the authors for their patience during my review of this manuscript. I personally thank the authors for conducting this thoughtful survey - despite the pandemic setbacks. I recommend this encouraging paper for acceptance to PLOS ONE. Recognition of the obstacles that caregivers and individuals with CP face when being included in research is a necessary addition to the literature and empowerment of the disability community.

Thank you for your kind comments and for taking the time to review the manuscript.

(4.1) In general, there is a narrative of "indirect benefit" vs "direct benefit" in the Travel Needs and Preferences category under Part III of Methods section. From my understanding, research does not directly benefit those who participate (that would be more of a QI initiative) but rather in some instances there may be the prospect of benefit. Authors can read more here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2945615/. Friedman et al argue about “direct” and “indirect” benefits in the context of research on vulnerable populations and children and try to outline what counts as a potential direct benefit, if any.

Thank you for this insightful comment. While we agree with the definitions outlined by Friedman et al., our approach differed in the survey design. We have added definitions of the “potential for a direct benefit study” vs. an “indirect benefit study” using the language that was in our survey (pg. 6, lines 148-152 and Table 2 in the manuscript with tracked changes). Our intention when asking these questions was to differentiate between studies such as clinical trials (potential for direct benefit) and basic science investigations (indirect benefit). We agree that we did not control for participants’ understanding and interpretation of the likelihood for direct benefit, which is the rationale for using the same definition for readers. This limitation has been addressed in the discussion section (pg. 18, lines 357-360).

(4.2) Page 14, line 255: Mean response time is reported for “travel time for indirect benefit study” vs “travel time for direct benefit study”. Again, it’s still not clear if this is the participant's perception of the benefit that they may derive from their participation in the study? Research aims to benefit future patients and often participation is altruistic, where research outcomes can benefit the scientific understanding of CP for future treatment and intervention. There is uncertainty around the interventions/therapies being studied. Your findings regarding the barrier “travel time” in light of “direct” vs “indirect” benefits could possibly help ethics review committees make prospective decisions on whether the research in question offers an appropriate risk-benefit profile, as certain prospects of benefit can be seen as decreasing impact of barriers and maybe even the risk involved to those participating. More studies like this survey are recommended.

We have provided the definitions of “potential for direct benefit” vs. “indirect benefit” according to the language in the survey (pg. 6, lines 148-152 and Table 2). Our question about travel time was related to convenience rather than risk and is therefore likely less relevant to an ethics committee determination. We agree that how benefits are perceived by potential participants is important and should be studied in the future.

(4.3) I think a brief explanation on what the authors mean by "indirect benefit study" and "direct benefit study" would be meaningful. Maybe an inherent barrier is education regarding the purpose of research, since "indirect benefit" and "direct benefit" is seen impacting barriers like travel time. Mention of therapeutic misconception (inflating likelihood of benefit from research participation by seeing research as routine care) would be useful. Read here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3690536/

As mentioned above, we defined these terms very broadly for participants. We have edited the limitations section of the discussion to acknowledge that we did not address considerations such as therapeutic misconception (pg. 18, lines 357-360). We agree that this is an important topic for investigation in future studies.

(4.4) Page 18, line 335: Again, is this their perception of benefit?

Yes, this is the participants’ perception of benefit. We have addressed this by clarifying the phrase in the relevant sentence: “...studies with and without potential for direct benefit” (pg. 18, line 343).

(5) “Research” is referred to broadly. Maybe in the future it would be useful to understand if the barriers to research are associated with the type of research involvement (e.g., research comparing routine standard of care interventions vs research on pre-approval CP therapeutics).

Thank you for this comment. We agree that this would be an interesting direction for future exploration.

(6) Page 18, line 352: This is an excellent point among many. Valuable and well-designed research should be informed by stakeholder and patient perspectives.

Thank you for this kind comment.

(7) Limitations are well addressed. Great solutions proposed on CP stakeholder engagement.

Thank you, we’re glad to see a shift towards this engaged approach occurring in research and hope to accelerate it.

(8) Page 19, line 363: “…true partners in research that aims to benefit *people like* them."

This sentence has been edited as proposed (pg. 19, lines 378-

Submitted filename: PLOS One Response to Reviewers.docx

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17 Dec 2021

Motivators and barriers to research participation for individuals with cerebral palsy and their families

PONE-D-21-23605R2

Dear Dr. Sukal-Moulton,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

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Prof. Ritesh G. Menezes, M.B.B.S., M.D., Diplomate N.B.

Academic Editor

PLOS ONE

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #3: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #3: (No Response)

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #3: (No Response)

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #3: (No Response)

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #3: (No Response)

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #3: (No Response)

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Reviewer #3: No

13 Jan 2022

PONE-D-21-23605R2

Motivators and barriers to research participation for individuals with cerebral palsy and their families

Dear Dr. Sukal-Moulton:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

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