Abnormal vocal behavior predicts executive and memory deficits in Alzheimer’s disease

Publication date: Available online 3 January 2017
Source:Neurobiology of Aging
Author(s): Kamalini G. Ranasinghe, Jeevit S. Gill, Hardik Kothare, Alexander J. Beagle, Danielle Mizuiri, Susanne M. Honma, Maria Luisa Gorno-Tempini, Bruce L. Miller, Keith A. Vossel, Srikantan S. Nagarajan, John F. Houde
Speakers respond automatically and rapidly to compensate for brief perturbations of pitch in their auditory feedback. The specific adjustments in vocal output require integration of brain regions involved in speech-motor-control in order to detect the sensory-feedback-error and implement the motor-correction. Cortical regions involved in the pitch-reflex phenomenon are highly vulnerable targets of network disruption in Alzheimer's disease (AD). We examined the pitch-reflex in AD patients (n=19) compared to an age-matched control group (n=16). We measured the degree of behavioral compensation (peak-compensation) and the extent of the adaptive response (pitch-response-persistence). Healthy-controls reached a peak-compensation of 18.7±0.8 cents, and demonstrated a sustained compensation at 8.9±0.69 cents. AD patients, in contrast, demonstrated a significantly elevated peak-compensation (22.4±1.2 cents, P<0.05), and a reduced sustained response (pitch-response-persistence, 4.5±0.88 cents, P<0.001). The degree of increased peak-compensation predicted executive dysfunction, while the degree of impaired pitch-response-persistence predicted memory dysfunction, in AD patients. The current study demonstrates pitch-reflex as a sensitive behavioral index of impaired prefrontal modulation of sensorimotor integration, and compromised plasticity mechanisms of memory, in AD.



http://ift.tt/2ivJWXV