Emotional prosody of Parkinsonians following subthalamic nucleus deep brain stimulation

- Perception and expression of emotional prosody in Parkinsonians treated with subthalamic nucleus DBS were studied.
- Potential differences between Deep Brain Stimulation on and off states were investigated.
- Perception of prosody showed no consistent behavior under stimulation states.
- The expression of prosody, on the other hand, seems to deteriorate when stimulation is applied.

ObjectivesInvestigation of potential differences in both perception and expression of emotional prosody between the stimulation and non-stimulation state of Parkinson's disease (PD) patients treated with subthalamic nucleus Deep Brain Stimulation (STN-DBS).Materials and methodsA group of 16 PD patients were studied for two distinct research tasks. In the first one (estimation of prosody perception), a battery of words/sentences recorded by a professional announcer was administered to them in STN-DBS-on state and they were asked to select the correct prosody each time. The procedure was repeated in the STN-DBS-off state. In the second task (estimation of prosody expression), the patients were given a second battery of recordings using the same words and sentences but in different prosody and were asked to reproduce the prosody they heard, again in STN-DBS-on/off states. Their recorded voice was later given to 50 healthy control listeners, aware of the target prosody, who evaluated the patients' ability to correctly reproduce the prosody using a 6-point scale.ResultsThe overall performance of the PD participants in the perception of prosody task was 45.3% and 49.8% for the DBS-on and DBS-off state respectively (p = 0.173). The specific percentages of correct perception of different types of prosody ranged from 31.3% to 62.5% and did not differ significantly between the DBS states. The rates of misclassifications were not consistently in favor of DBS-on or DBS-off state. Prosody expression in DBS-off state was rated by normal listeners as better compared to the DBS-οn state.ConclusionsRegarding prosody perception, no significant differences were found either in the overall performance of PD patients or in the prosody-specific correct classification rates. However, particular stimulation states favor different misclassification directions. DBS-on state negatively influences the expression of emotional prosody in the speech of patients with Parkinson's disease.