PREVALENCE AND CORRELATES OF NEUROPSYCHOLOGICAL DEFICITS IN AMYOTROPHIC-LATERAL-SCLEROSIS

Objective-To determine the prevalence and correlates of neuropsycholog ical impairment in a large cohort (n = 146) of patients with typical, sporadic (nonfamilial) amyotrophic lateral sclerosis. Methods-A batter y of neuropsychological tests was administered to patients with amyotr ophic lateral sclerosis who were attending a monthly outpatient clinic or who were in hospital undergoing diagnostic tests. Results-Comparin g individual patient's scores with relevant normative data, 35.6% of t he patients displayed evidence of clinically significant impairment, p erforming at or below the 5th percentile on at least two of the eight neuropsychological measures. Deficits were most common in the areas of problem solving, attention/mental control, continuous visual recognit ion memory, word generation, and verbal free recall. Impairment was mo st prevalent in patients with dysarthria (48.5%), but 27.4% of non-dys arthric patients were also impaired. Impaired patients had more severe or widespread symptoms of amyotrophic lateral sclerosis than non-impa ired patients, and had fewer years of education. Conclusion-Neither th e conventional wisdom that cognition is intact in nearly all patients with amyotrophic lateral sclerosis, nor more recent suggestions that c ognition is often at least mildly impaired seems to be correct. A mino rity of patients with amyotrophic lateral sclerosis displayed evidence of significant impairment, Dysarthria, low education, and greater sev erity of motor symptoms were risk factors for impairment.