Parkinsonian voice acoustic analysis in real-time after stereotactic thalamotomy

The voice acoustic structure in 7 male patients with Parkinson's disease was analyzed 1 week before and 1 week after right-sided thalamotomy. The voice signal of the 3-digit number 306 was analyzed in real-time using a digital frequency analyzer. The average value of intensity level during the initial segment of the speech signal became higher after thalamotomy (75.04 vs. 59.24 dB). The voice fundamental frequency increased from 104 to 122 Hz. Before the operation, the energy focus of the speech signal was 73.19 vs. 76.87 dB postoperatively. The voice formants F1 and F2 shifted to the higher energy and frequency regions. The total sound pressure level of the pronounced 3-digit number 306 became two times higher after operation. The overall fluency of pronunciation was improved.