Cognitive impairment in familial ALS

Abstract

Background: ALS is a progressive neurodegenerative disorder that affects upper and lower motor neurons. Recent reports demonstrate cognitive impairment in patients with sporadic ALS (sALS).

Objective: To test whether patients with familial ALS (fALS) have cognitive impairment and whether it is of the same type and degree as observed in sporadic ALS.

Methods: Thirty-seven consecutive patients with fALS underwent comprehensive neuropsychological testing. Cognitive impairment was categorized by 1) cluster analysis of non-timed, non-motor dependent neuropsychological tests, 2) cutoff scores, and 3) clinical impression.

Results: By cluster analysis, 23 of 37 (62%) patients with fALS and 190 of 392 (48.5%) patients with sALS had cognitive impairment (difference not significant). Similar rates of impairment were found using clinical diagnostic criteria and cutoff score analysis. Neither motor scores nor the site of symptom onset correlated with cognitive impairment. Only age differed between the affected and unaffected fALS groups.

Conclusions: The prevalence and pattern of cognitive impairment in familial ALS (fALS) is similar to that of sporadic ALS. For patients with fALS, the site of symptom onset did not correlate with cognitive impairment, but age did. Future studies will determine whether cognitive impairment in fALS correlates with specific genetic mutations or polymorphisms.

GLOSSARY: AmNART = American National Reading Test; fALS = familial ALS; FTD = frontotemporal dementia; LM I = Logical Memory, immediate recall; LM II = Logical Memory, delayed recall; sALS = sporadic ALS; VR I = Visual Recognition, immediate recall; VR II = Visual Recognition, delayed recall; VSAT-Err = Verbal Series Attention Test errors.