Can rhythmic auditory cuing remediate language-related deficits in Parkinson's disease?

Neurodegenerative changes of the basal ganglia in idiopathic Parkinson's disease (IPD) lead to motor deficits as well as general cognitive decline. Given these impairments, the question arises as to whether motor and nonmotor deficits can be ameliorated similarly. We reason that a domain-general sensorimotor circuit involved in temporal processing may support the remediation of such deficits. Following findings that auditory cuing benefits gait kinematics, we explored whether reported language-processing deficits in IPD can also be remediated via auditory cuing. During continuous EEG measurement, an individual diagnosed with IPD heard two types of temporally predictable but metrically different auditory beat-based cues: a march, which metrically aligned with the speech accent structure, a waltz that did not metrically align, or no cue before listening to naturally spoken sentences that were either grammatically well formed or were semantically or syntactically incorrect. Results confirmed that only the cuing with a march led to improved computation of syntactic and semantic information. We infer that a marching rhythm may lead to a stronger engagement of the cerebello-thalamo-cortical circuit that compensates dysfunctional striato-cortical timing. Reinforcing temporal realignment, in turn, may lead to the timely processing of linguistic information embedded in the temporally variable speech signal.