The relationship of cognitive impairment with neurological and psychiatric variables in multiple sclerosis patients

Cognitive impairment (CI) in multiple sclerosis (MS) can develop any time. CI is associated with the degree of neuronal loss, but disease duration, fatigue, comorbid affective disorder, and drug dose may also affect cognition. Our aim was to assess which cognitive domain was disturbed primarily in mild MS patients and to see whether CI was related with clinical and psychiatric features.

Neurological and psychiatric evaluation of 31 MS patients and 31 age, sex, and education-matched healthy controls were made with Structured Clinical Interview for Axis I Disorders (SCID-I). Depression, anxiety, functionality, fatigue, and disability scoring were determined with Hamilton Depression-Anxiety scales, Global Assessment of Functionality, Fatigue Severity and Expanded Disability Status Scales. Cognitive functions were assessed using Mini Mental, Serial Digit Learning, Verbal and Nonverbal Cancellation, Stroop and Rey Auditory Verbal Learning tests.

Retrieval from long-term memory and psychomotor speed were significantly worse in MS group. CI was correlated with disease duration, number of attacks, and physical disability but not with depression and anxiety severity. Disease duration predicted disturbances in recall and psychomotor speed, whereas fatigue and disability predicted depression.

Psychomotor speed and memory were primarily impaired in MS patients, and CI was closely associated with clinical aspects of MS rather than with depression and anxiety.