Background. Amyotrophic lateral sclerosis (ALS) has long been considered a pure motor neurodegenerative disease. However, now, extra-motor manifestations such as cognitive-behavioral disorders are considered not rare and are even a severity factor of the disease. Experiencing anosognosia (i.e., the inability to recognize neurological symptoms) might affect care and treatment compliance in ALS. Regardless, this pivotal feature has been little investigated.

Objectives. By comparing patients’ and caregivers’ reports, we analysed whether patients with ALS would experience a lack of awareness about their executive disorders and their apathy symptoms.

Methods. From the ALS reference center in Paris, we included 85 patients (47 men, mean [SD] age 60.5 [12] years and ALS-Functional Rating Scale-revised score 8 to 46) and their primary family caregivers who all completed the Dysexecutive Questionnaire (DEX) and the Apathy Evaluation Scale (AES). Overall scores and answers were compared by agreement/disagreement statistical methods.

Results. Caregivers reported higher levels of cognitive-behavioral disorders than did patients, but reports matched when cognitive-behavioral disorders were absent or mild. With published DEX and AES cutoffs, 32% and 51% of patients had executive disorders and apathy, respectively. In these patients with significant impairment, Bland-Altman plots (i.e., visual display agreement that represents the difference between the patient’s and caregiver’s scores as a function of their average) showed a strong discrepancy between joint reports: patients underestimated their symptoms by a mean bias of -6.81 DEX points (95% confidence interval -11.88, -1.75) and -8.85 AES points (95% confidence interval -11.72, -5.98). We found no clear relationship between bulbar or spinal ALS subtypes and anosognosia.

Conclusions. ALS patients with a cognitive-behavioral phenotype show anosognosia by a mismatch between self and proxy reports, which warrants further investigation in neuroimaging. Systematic longitudinal screening of anosognosia is needed to propose targeted psychoeducation in patient–caregiver dyads showing disagreement.