Publication:

A comparative study of long term average spectrum measures on spontaneous speech tasks between patients with Parkinson’s disease and age matched normals

Background Long term average spectrum (LTAS) is a robust tool in assessing voice characteristics over a period of time. Individuals with Parkinson’s disease (PD) exhibit speech impairments, which includes monopitch and monoloudness, reduced stress, tremulous voice and inappropriate silences. Since, there are no studies in Indian context to analyse the spontaneous speech of patients with PD through LTAS and spontaneous speech provides naturalness in speech, the present study is an attempt to compare spontaneous speech between patients with PD and age matched normals using LTAS.

Methods A total of 30 participants aged 50-70 years were considered for the study among which 15 were patients with PD (group-I) and 15 were age matched normals (group-II). The LTAS parameters - mean spectral energy (MSE), first spectral peak (FSP), spectral tilt (ST), three spectral slope (SS) measures (SSF0-1kHz, SS1-5kHz, and SS ratio), four spectral moment analysis (mean, standard deviation, skewness, and kurtosis), jitter and shimmer were taken for analysis. Mann-Whitney U test was performed for statistical analyses.

Results The results showed there was significant difference in mean values of MSE, FSP, ST, four SM measures, jitter and shimmer. However, there was no significant difference in mean values of three SS measures.

Conclusions To conclude the study it can be said that patients with PD demonstrate specific LTAS characteristics that are different from normals.