Emotional speech in Parkinson's disease.

Patients with Parkinson's disease (PD) tend to speak monotonously with minor modulation of pitch and intensity. The goal of this study was to find out whether these speech changes can be explained mainly by motor impairment, i.e. akinesia and rigidity of the articulatory apparatus, or whether alterations of emotional processing play an additional role. Sixteen patients with mild PD and 16 healthy controls (HC) were compared. Fundamental frequencies (pitch) and intensities (loudness) were determined as (1) maximal upper and lower values achieved in nonemotional speech (phonation capacity), (2) upper and lower values used when speaking "Anna" in emotional intonation (neutral, sad, happy) as requested (production task), or (3) when imitating a professional speaker (imitation task). Although groups did not significantly differ in their phonation capacity, patients showed a significantly smaller pitch and intensity range than HC in the production task. In the imitation task, however, ranges were again similar. These results suggest that alterations of emotional processing contribute to speech changes in PD, especially regarding emotional prosody, in addition to motor impairment.

Perception of emotional speech in Parkinson's disease.

Nonmotor symptoms in Parkinson's disease (PD) involving cognition and emotionality have progressively received attention. The objective of the present study was to investigate recognition of emotional prosody in patients with PD (n = 14) in comparison to healthy control subjects (HC, n = 14). Event-related brain potentials (ERP) were recorded in a modified oddball paradigm under passive listening and active target detection instructions. Results showed a poorer performance of PD patients in classifying emotional prosody. ERP generated by emotional deviants (happy/sad) during passive listening revealed diminished amplitudes of the mismatch-related negativity for sad deviants, indicating an impairment of early preattentive processing of emotional prosody in PD.

Tracking of multiple sound sources defined by interaural time differences: brain potential evidence in humans.

Among other cues, interaural time differences (ITD) can be used to compute the location of a sound. To investigate whether ITD can be used for the preattentive detection of sounds coming from a different location than standard sounds (P=0.7, no ITD), left and right 'far' (900 micros ITD, 80 degrees excentricity) and 'near ' (300 micros ITD, 30 degrees ) deviant stimuli (each deviant P=0.075) were presented via headphones. While 15 young healthy subjects passively listened to these sequences, the mismatch negativity (MMN) of the event-related potential was obtained for the deviant sounds. MMN was reliable for all four deviants but larger for the far-lateralized sounds. Moreover, MMN was larger contralateral to the location of the deviant. This indicates a role of preattentive mechanisms in the spatial analysis of auditory scenes.