Cognitive impairment in patients with amyotrophic lateral sclerosis: a neuropsychological perspective

Abstract

Traditionally, ALS has been viewed as a disease of the motor neuron system, characterized by degeneration of both the upper and lower motor neurons, with no compromise to cognitive functions. However, recent studies have shown that structural and pathological changes are not confined to motor areas and that these changes correlate with cognitive dysfunction. Despite these findings, the nature and the extent of cognitive changes in ALS have not yet been clearly defined. Studies differ in their findings with regard to the identification of affected cognitive domains, frequency, and extent of the impairment. The problem of cognitive evaluation in patients with ALS, and a possible reason for disparities between studies, is motor impairment in patients with ALS: many standard neuropsychological tests used for the evaluation of cognitive functions rely on participants’ intact motor function, but most previous studies have not appropriately accounted for motor impairment in ALS. In this review we highlight the high prevalence and variability of cognitive change in ALS. Major neuropsychological findings in this field are summarized. We also outline the options and latest recommendations for neuropsychological evaluation of ALS patients’ cognitive change in the clinical setting. Special emphasis is given to the problem of motor impairment in ALS. We highlight the multilayer importance of reliable identification of cognitive change in this disease, including implications for clinical work.

Keywords

• amyotrophic lateral sclerosis
• cognitive functions
• cognitive impairment
• neuropsychological research
• motor impairment