Extraction of Phonation Measures Affected by Parkinson Disease

Parkinson’s disease (PD) is a chronic neuro-degenerative disorder caused by the damage or loss of dopamine producing cells in the substantia nigra of the brain. This deficiency in the dopamine affects the neurotransmitter systems which are responsible for a variety of motor and non-motor deficits. The motor and non-motor deficits involve areas such as speech, EEG, gait, mood, sensation, thinking and behavior. The various speech subsystems affected by PD includes phonation, articulation, respiration and prosody. These PD affected speech subsystems are typically assessed using several acoustic measurements. The measures of phonation influenced by PD include fundamental frequency, jitter, shimmer, NHR and HNR ratios and voice onset time. This paper provides a systematic review of different algorithms used for the extraction of these phonation measures affected by Parkinson disease which may be helpful in diagnosing and or in classifying the severity of the disease. Keywords—Jitter ,phonation measures,pitch,shimmer, voice onset time.