Voice Characteristics of Patients with Pallido-Ponto-Nigral Degeneration (PPND) and Their Application to Pre-Symptomatic Detection in At-Risk Relatives
J Liss, K Krein-Jones, A Karine-Lamoureux, Z Wszolek, J Caviness
The purposes of this investigation were 1) to define the properties and temporal sequence of voice deterioration through longitudinal study of pallido-ponto-nigral degeneration (PPND), 2) to compare these findings to a cross-section of symptomatic patients at various stages of PPND, and 3) to apply these data to asymptomatic at-risk relatives for possible preclinical detection of PPND. The voices of nine people were examined acoustically (Multi-Dimensional Voice Program) and perceptually in the context of a larger study of the PPND kindred. Of the nine, two were followed longitudinally, three symptomatic patients at various disease stages were seen once, and four others seen once were at-risk but asymptomatic. The most prominent features in the longitudinal measures included F0 control and modulation deficits, amplitude control and modulation deficits, presence of intermittent tremor and vocal flutter, and voice quality deficits. In addition, disease progression was accompanied by increases in inter-and intrasession variability; the number acoustic parameters affected; and the distance of these measures from normative values. Cross-sectional voice findings for the three symptomatic patients were consistent with the longitudinal data. Voice analysis correctly identified disease status in 3 of the 4 asymptomatic patients, suggesting voice characteristics to be an early harbinger of disease onset.