| Literature DB >> 33149931 |
Leif Er Simmatis1, Albert Y Jin, Sean W Taylor1, Etienne J Bisson1, Stephen H Scott1, Moogeh Baharnoori1.
Abstract
BACKGROUND: Multiple sclerosis (MS) causes pervasive motor, sensory and cognitive dysfunction. The Expanded Disability Status Scale (EDSS) is the gold standard for assessing MS disability. The EDSS is biased towards mobility and may not accurately measure MS-related disabilities in the upper limb or in cognitive functions (e.g. executive function).Entities:
Keywords: Robotic exoskeleton; cognitive function; progressive multiple sclerosis; relapsing remitting multiple sclerosis; sensory and motor function
Year: 2020 PMID: 33149931 PMCID: PMC7580159 DOI: 10.1177/2055217320964940
Source DB: PubMed Journal: Mult Scler J Exp Transl Clin ISSN: 2055-2173
Detailed task descriptions.
| Domain | Task name | Description |
|---|---|---|
| Sensory | Arm position matching (APM) | This task required participants to detect the location of one hand, moved by the robot, and indicate this by mirror-matching the position using their other hand. Vision of the hands was obscured.[ |
| Motor | Visually guided reaching (VGR) | This task required participants to make quick and accurate reaches to a random series of 4 targets from a central starting point. Hand position was indicated using a white cursor light.[ |
| Ball on bar (BOB) | Participants controlled a horizontal bar using both hands, with a ball balanced in the middle. There are 3 levels in this task: the first, in which the ball is stationary on the bar; the second, in which the ball can slide; finally, the third, in which it can roll and easily fall off the bar (the task resets in that case). The goal is to bring the ball to as many targets as possible within the 1 minute allotted per level25. | |
| Object hit (OH) | Participants had to control green paddles, one with each hand, and hit as many red balls away from them (that were falling towards them) as possible. The task lasts 2 1/2 minutes and gets progressively harder, with balls falling faster as time progresses26 . | |
| Object hit & avoid (OHA) | This task is almost the same as OH, except that only 2/8 possible objects should be hit and the remaining 6/8 should be avoided. This task therefore tests rapid decision making27. | |
| Cognitive | Reverse visually guided reaching (RVGR) | RVGR is almost the same as VGR except that after getting to the first central target, the cursor indicating the hand position moves in the opposite direction of the hand. The objective is to override the natural inclination to reach towards the red target (the spatial goal) and instead form a new motor plan to attain the visual goal (bringing the white light into the red target)28. |
| Spatial span (SPS) | Participants had to remember a sequence of square targets as presented to them (same order) on a 3 × 4 grid of square targets. After successful recall of a sequence, the length of the sequence increased by 1 target. After an unsuccessful attempt, the length of the sequence was decreased by 1 target. This task is similar to the Corsi block-tapping test29. | |
| Trail making test (TMT) | This task was similar to the pen-and-paper version of the trail making test. In part A, participants had to navigate the cursor between 25 targets numbered 1–25 in order as quickly as possible. In part B, participants had to navigate between alternating numbers and letters, i.e. 1-A-2-B-…, as quickly as possible. In the B variant, the sequence ended on the number 13 and thus the number of targets was the same as in part A ( |
Figure 1.The Kinarm robot, tasks, and statistical properties of Task Scores. (a) The Kinarm Endpoint lab includes two robotic linkages with handles that are grasped by the participant and permits movement in the horizontal workspace. A virtual reality system projects objects into the horizontal workspace. (b) The Kinarm Exoskeleton lab includes two robotic linkages with troughs to support the arms in the horizontal plane. The robotic system is attached to a wheelchair frame and the subject and robotic linkage is wheeled up to a virtual reality system. (c) Eight behavioural tasks were performed, spanning motor (VGR, BOB, OH, OHA), cognitive (RVGR, SPS, TMT) or sensory (APM) behaviours. (d) The Task Score is a one-sided measure, and the quantiles of its cumulative density function (CDF) are similar to those of the standard Normal distribution. E.g. a Task Score of 1 represents 68.3% of the area under the curve, the same as the area under the standard Normal CDF for a Z-value of ±1.
MS cohort demographics and clinical score summary.
|
| 43 |
|---|---|
| Age (median [IQR]) years | 50.0 [15.4] |
| Sex (% Female) | 74 |
| Handedness (% Right-handed) | 93 |
| Education (median [IQR]) years | 14 [2] |
| RRMS/Progressive MS (number) | 30/13 |
| EDSS (median [IQR]) | 2.5 [2.5] |
| T25W (mean [SD]) seconds | 5.8 [3.3] |
| MoCA (median [IQR) score | 27[2] |
| MoCA ( | 10/43; 3/43 |
| SDMT (median [IQR]) score | 47.0 [14.0] |
| 9HPT-D (mean [SD]) seconds | 25.6 [18.5] |
| 9HPT-ND (mean [SD]) seconds | 29.6 [29.1] |
| MFIS-21 (median [IQR]) score | 36.5 [38.8] |
IQR = Interquartile range; SD = Standard deviation; -D/-ND = Dominant or non-dominant arm; EDSS = Expanded disability status scale; T25W = Timed 25-foot walk; MoCA = Montreal cognitive assessment; SDMT = symbol-digit modalities test; HPT9 = 9-hole peg test; MFIS-21 = Modified fatigue impact scale, 21-question variant.
Figure 2.Task Scores for individuals with MS across all robotic tasks. Individuals are sorted in order of increasing EDSS score (left to right), with missing EDSS values on the rightmost part of the axis (marked with ‘NA’). Squares marked with ‘X’ indicate missing values. Task Scores <1.96 (not impaired) are in lightest grey, whereas Task Scores >1.96 (impaired) are in darkening shades of grey (darker=poorer performance). Note that rms_mot=RMS of motor Task Scores, rms_cog=RMS of cognitive Task Scores, and rms_sen=RMS of sensory Task Scores (i.e. APM-D and APM-ND).
Proportions of impaired individuals in the MS cohort for each robotic task performed.
| Task | Impairment rate |
|---|---|
| APM-D | 8/41 (20%) |
| APM-ND | 4/41 (10%) |
| VGR-D | 9/42 (21%) |
| VGR-ND | 15/42 (36%) |
| VGR-IL | 17/42 (40%) |
| BOB | 10/40 (25%) |
| OH | 12/41 (29%) |
| OHA | 11/41 (27%) |
| RVGR-D | 18/42 (43%) |
| RVGR-ND | 16/42 (38%) |
| RVGR-IL | 17/42 (40%) |
| SPS | 5/36 (14%) |
| TMT | 9/41 (22%) |
| Sensory RMS | 4/41 (10%) |
| Motor RMS | 9/39 (23%) |
| Cognitive RMS | 14/35 (40%) |
Number of impaired (%) are presented. Impairment is defined as a Task Score > 1.96; -D/-ND/-IL indicate Dominant, non-dominant arm, or interlimb score; RMS=Root mean square.
Figure 3.Cumulative sums of Task Scores in MS and simulated control cohorts. Expected values for control participants are plotted as thin grey lines based on means and standard deviations for healthy individuals. People with MS are plotted with black circles. The vertical dashed lines indicate the impairment threshold of 1.96. Percentages of participants are indicated on the y-axis (along with the task label).
Figure 4.Correlations between all clinical and robotic variables (MS group only). Blue cells indicate negative correlations and red cells indicate positive correlations. Values that were significant after FDR correction are bolded and in larger font. Note that rms_mot = root mean-square (RMS) of motor Task Scores, rms_cog = RMS of cognitive Task Scores, and rms_sen = RMS of sensory Task Scores (i.e. APM-D and APM-ND). ‘-D’ indicates dominant arm, ‘-ND’ indicates non-dominant arm.