Amy L Lebkuecher1, Nancy D Chiaravalloti2, Lauren B Strober3. 1. Department of Psychology, The Pennsylvania State University, 140 Moore Building, University Park, PA 16802, United States. Electronic address: axl413@psu.edu. 2. Cognitive Functioning and Cognitive Rehabilitation Laboratory, Kessler Foundation, 120 Eagle Rock Avenue, East Hanover, NJ 07936, United States; Department of Physical Medicine & Rehabilitation, Rutgers New Jersey Medical School, Medical Science Building, 185 South Orange Avenue, Newark, NJ 07103, United States. 3. Department of Physical Medicine & Rehabilitation, Rutgers New Jersey Medical School, Medical Science Building, 185 South Orange Avenue, Newark, NJ 07103, United States; Center for Neuropsychology and Neuroscience Research, Kessler Foundation, 120 Eagle Rock Avenue, East Hanover, NJ 07936, United States.
Abstract
BACKGROUND: While cognitive deficits in memory and processing speed have been well-documented in individuals with multiple sclerosis (MS), language is largely considered to be intact. Verbal fluency deficits observed in MS are often attributed to impaired processing speed and executive functions rather than language ability. The current study evaluates the contribution of various cognitive factors to verbal fluency including language ability, oral-motor speed, processing speed, and executive functions. METHODS: We analyzed pre-existing data from seventy-four (74) individuals with MS who completed a battery of neuropsychological tests designed to assess individual ability for various cognitive factors. We conducted linear multiple regression analyses with letter and category verbal fluency as outcome variables and performance on other cognitive domains (e.g., processing speed, executive functioning) as predictors. RESULTS: Both vocabulary and processing speed predicted letter fluency while only vocabulary predicted category fluency. These findings suggest that the observed verbal fluency deficits in MS may reflect both impaired language ability and processing speed. CONCLUSION: We propose that further research on language ability in MS is needed to determine if comprehensive neuropsychological test batteries for persons with MS should include tests of language ability to fully understand the cognitive profile of any given patient. Given the importance of language ability, it may be necessary to conduct a more thorough assessment of language in individuals with MS who experience a deficit in this domain.
BACKGROUND: While cognitive deficits in memory and processing speed have been well-documented in individuals with multiple sclerosis (MS), language is largely considered to be intact. Verbal fluency deficits observed in MS are often attributed to impaired processing speed and executive functions rather than language ability. The current study evaluates the contribution of various cognitive factors to verbal fluency including language ability, oral-motor speed, processing speed, and executive functions. METHODS: We analyzed pre-existing data from seventy-four (74) individuals with MS who completed a battery of neuropsychological tests designed to assess individual ability for various cognitive factors. We conducted linear multiple regression analyses with letter and category verbal fluency as outcome variables and performance on other cognitive domains (e.g., processing speed, executive functioning) as predictors. RESULTS: Both vocabulary and processing speed predicted letter fluency while only vocabulary predicted category fluency. These findings suggest that the observed verbal fluency deficits in MS may reflect both impaired language ability and processing speed. CONCLUSION: We propose that further research on language ability in MS is needed to determine if comprehensive neuropsychological test batteries for persons with MS should include tests of language ability to fully understand the cognitive profile of any given patient. Given the importance of language ability, it may be necessary to conduct a more thorough assessment of language in individuals with MS who experience a deficit in this domain.