Sensory Integration Deficits in Neurodegenerative Diseases: Implications for Apraxia

Abstract Objective Apraxia is the inability to perform voluntary, skilled movements following brain lesions, in the absence of sensory integration deficits. Yet, patients with neurodegenerative diseases (ND) may have sensory integration deficits, so we tested the associations and dissociations between apraxia and sensory integration. Methods A total of 44 patients with ND and 20 healthy controls underwent extensive testing of sensory integration (i.e., localization of tactile, visual, and proprioceptive stimuli; agraphesthesia; astereognosis) and apraxia (i.e., finger dexterity, imitation, tool use). Results The results showed (i) that patients with Alzheimer’s disease, corticobasal syndrome, or posterior cortical atrophy were impaired on both dimensions; (ii) An association between both dimensions; (iii) that when sensory integration was controlled for, the frequency of apraxia decreased dramatically in some clinical subgroups. Conclusion In a non-negligible portion of patients, the hypothesis of a disruption of sensory integration can be more parsimonious than the hypothesis of apraxia in case of impaired skilled gestures. Clinicians and researchers are advised to integrate sensory integration measures along with their evaluation of apraxia.