Oralmotor slowing in multiple sclerosis: relationship to neuropsychological tasks requiring an oral response

Although most neuropsychological batteries used with multiple sclerosis (MS) patients now exclude tests that require significant motor writing or manual manipulation speed, many of the most sensitive commonly used cognitive tests nonetheless require some type of rapid oral motor response. The aim of this study is to examine the extent to which primary oral motor articulation speed problems of individuals with MS contribute to performance and group differences on neuropsychological tasks requiring a rapid spoken response. Fifty MS patients and 50 healthy controls were administered the PASAT, COWAT, Animal Naming, and SDMT tests, in addition to a measure of rudimentary oral motor speed known as the maximum repetition rate of syllables and multisyllabic combinations (MRR) task. Regression analyses revealed that the amount of variance accounted for by the group (MS-Control) variable was reduced the following amounts for the tasks when the MRR was entered before the group variable: SDMT, 10% to 6%; PASAT, 4% to 2%; COWAT, 5% to 2%; Animal Naming, 11% to 7%. Our data suggest that rudimentary oral motor speed is slowed in MS patients and makes an important contribution to group differences in performance on commonly used neuropsychological tasks requiring a rapid spoken response.