Residual signal auto-correlation to evaluate speech in Parkinson’s disease patients

Abstract

-Objective: To evaluate the maximum residual signal auto-correlation also known as pitch amplitude (PA) values in patients with Parkinson's disease (PD) patients. Method: The signals of 21 Parkinson's patients were compared with 15 healthy individuals, divided according age and gender. Results:S t a t i s t i c a l d i ff e rence was seen between groups for PA, 0.39 for controls and 0.25 for PD. Normal value threshold was set as 0.3; (p<0.001). In the Parkinson's group 80.77%, and in the control group only 12.28%, had a PA < 0 . 3 demonstrating an association between these variables. The dispersion diagram for age and PA for PD individuals showed p=0.01 and r=0.54. There was no significant diff e rence in relation to gender and PA between g ro u p s . Conclusion: The significant diff e rences in pitch's amplitude between PD patients and healthy individuals demonstrate the methods specificity. The results showed the need of prospective contro l l e d studies to improve the use and indications of residual signal auto-correlation to evaluate speech in PD patients.KEY WORDS: Parkinson's disease, speech analysis, residual signal.A u t o -c o rrelação do sinal residual para avaliação da fala em pacientes com doença de Parkinson RESUMO -Objetivo: Avaliar autocorrelação do sinal residual também denominado como amplitude do pitch (PA) em pacientes com doença de Parkinson (PD). Método: Os valores de PA, estratificados de acordo com idade e sexo, em 21 pacientes com doença de Parkinson foram analisados e comparados aos dados obtidos em 15 indivíduos sadios. Resultados: Foi determinada diferença estatística para a PA entre os dois grupos (p<0,001; 0,39 para os controles e 0,25 para PD), considerando os valores normais como >0,3. Nos pacientes com PD 80,77% dos pacientes tinham a PA <0,3, enquanto que entre os controles somente 12,28% apresentavam valores abaixo de 0,3. O diagrama de dispersão para idade e sexo para os doentes com PD mostraram um p=0,001 e r=0,54. Não houve diferença em relação a sexo e idade entre os gru p o s . Conclusão: A significativa diferença da PA entre pacientes com PD e controles demonstra a especificidade da análise. Os resultados apontam para a necessidade de estudos controlados, prospectivos, para implementar o uso e indicações da determinação da amplitude do pitch na avaliação da fala em pacientes com doença de Parkinson. PALAVRAS-CHAVE: doença de Parkinson, análise de fala, sinal residual.

Detecting Parkinson’s disease with sustained phonation and speech signals using machine learning techniques

“…Studies have shown that PD can be detected in its incipient phase [8]. Statistical techniques were used to evaluate the residual signal auto-correlation in Parkinson's disease patients and significant differences in pitches amplitude between patients and the healthy group was identified [9].…”

A new computer vision-based approach to aid the diagnosis of Parkinson's disease

“…where d is the displacement of the sample points used to compute the radius difference. 5 The following three features are computed based on the relative tremor r r…”

“…Expert systems based on machine learning techniques have been employed to this purpose, showing promising results [3]. Generally, these works are signal analysis-oriented, which means one can use the patient's voice to assess the level of the illness [4,5], since the voice capability is gradually compromised by PD. Little et al [4], for instance, presented a dataset composed of biomedical voice measurements from 31 male and female subjects, of which 23 patients were diagnosed with PD and 8 were healthy subjects.…”

Early Detection of Parkinson’s Disease from Micrographic Static Hand Drawings

“…However, most of the previous works considered signal analysis from patient's voice [17,23] as PD causes voice disorder. Few of the studies were based on MRI images [20,21].…”