Clinical usefulness of scales for evaluating cognitive impairment in patients with amyotrophic lateral sclerosis

Cognitive impairment is a common non-motor symptom of amyotrophic lateral sclerosis (ALS); however, scales suitable for detecting cognitive impairment in ALS patients in clinical practice are unclear. In this study, the Mini-Mental State Examination, Frontal Assessment Battery, and Montreal Cognitive Assessment (MoCA) were evaluated in 68 patients with ALS. The patients were classified into 3 groups based on the results of these clinical scales: group N, patients with scores higher than the cut-offs in all clinical scales; group M, patients with a score lower than the cut-off in one clinical scale; and group D, patients with scores lower than the cut-offs in two or three clinical scales. Clinical data were compared among the groups. Age at onset was significantly lower, and educational period was longer in group N than in group D. MoCA test reported the highest number of patients with a score lower than the cut-off value. The evaluation item of language in MoCA showed the lowest correct answer rate in group N, and evaluation items of executive function and memory in MoCA showed the lowest correct answer rates in group D. MoCA is the most sensitive clinical scale for evaluating cognitive impairment in ALS among the three scales.