Phonological processing in Parkinson's disease: a neuropsychological assessment

Patients with Parkinson's disease (PD) have cognitive deficits that cause functional impairments across several domains, including language. There is experimental evidence that basal ganglia and frontostriatal circuits are implicated in phonological processing, which leads to the hypothesis that a dysfunction of these circuits could be expressed behaviorally as phonological deficiencies in patients with PD. Using neuropsychological assessments, the present study aimed to explore the phonological processing abilities of patients in the initial stages of PD while controlling for other cognitive processes. The results showed lower scores in patients with PD on phonological tests with respect to a control group and these differences were independent of processes such as attention/working memory, long-term memory, thinking, and verbal language comprehension. However, there was an association between phonological skills and reading comprehension abilities. This finding implies a specific phonological deficit in terms of word reading.