The physical significance of acoustic parameters and its clinical significance of dysarthria in Parkinson’s disease

Abstract

Dysarthria is universal in Parkinson's disease (PD) during disease progression; however, the quality of vocalization changes is often ignored. Furthermore, the role of changes in the acoustic parameters of phonation in PD patients remains unclear. We recruited 35 PD patients and 26 healthy controls to perform single, double, and multiple syllable tests. A logistic regression was performed to differentiate between protective and risk factors among the acoustic parameters. The results indicated that the mean f0, max f0, min f0, jitter, duration of speech and median intensity of speaking for the PD patients were significantly different from those of the healthy controls. These results reveal some promising indicators of dysarthric symptoms consisting of acoustic parameters, and they strengthen our understanding about the significance of changes in phonation by PD patients, which may accelerate the discovery of novel PD biomarkers. Abbreviations PD Parkinson's disease HKD Hypokinetic dysarthria VHI-30 Voice Handicap Index H&Y Hoehn-Yahr scale UPDRS III Unified Parkinson's Disease Rating Scale Motor Score Parkinson's disease (PD), a chronic, progressive neurodegenerative disorder with an unknown etiology, is associated with a significant burden with regards to cost and use of societal resources 1,2. More than 90% of patients with PD suffer from hypokinetic dysarthria 3. Early in 1969, Darley et al. defined dysarthria as a collective term for related speech disorders. The classification of dysarthria includes flaccid dysarthria, spastic dysarthria, ataxic dysarthria, hypokinetic dysarthria, hyperkinetic dysarthria, unilateral upper motor neuron dysarthria and mixed dysarthria 4. The speech abnormalities of patients with PD are collectively termed hypokinetic dysarthria (HKD). These speech flaws are typically characterized by increased acoustic noise, a reduced intensity of voice, harsh and breathy voice quality, increased voice nasality, monopitch, monoloudness, speech rate disturbances, the imprecise articulation of consonants, the involuntary introduction of pauses, the rapid repetitions of words and syllables and sudden deceleration or acceleration in speech. Speech impairments are caused by impaired speech mechanisms during any of the basic motor processes involved in speech performance 5. The neuromotor speech sequence activates the muscles of the pharynx, tongue, larynx, chest and diaphragm through subthalamic secondary pathways. The anatomical substrate that could result in the abnormalities of PD phonetics may be reduced by the poor coordination of the sound-making muscles 6 .

Speech disorders in Parkinson’s disease - characteristics, assessment and treatment

“…The empirical data demonstrate abnormalities in minimum, average, and maximum fundamental frequency (F 0 ), jitter, and shimmer [22,23]. Some authors believe that changes in speech are universal during disease progression [23].…”

“…The empirical data demonstrate abnormalities in minimum, average, and maximum fundamental frequency (F 0 ), jitter, and shimmer [22,23]. Some authors believe that changes in speech are universal during disease progression [23]. There is an opinion that changes can be detected early by certain acoustic measurements and that reduced F 0 variability in spontaneous speech (especially intonation patterns) can be an early indicator of the disease even several years before diagnosis and clinical onset [24].…”

“…Prosodic abnormalities can be the main cause of impaired speech intelligibility and they negatively affect communication with other people [9]. The voice quality in these individuals is usually described as rough and breathy [23]. Most persons with PD experience difficulty varying the pitch and intensity of their voice due to the inability to perform fine vocal cord movements.…”

“…The voice range can also be reduced [30]. There are also palilalia and speech rate abnormalities, so the speech of these people may be accelerated or slow [23,31]. At first, the person speaks loudly.…”

Cognitive and language deficits in persons with Parkinson's disease

“…Kada je reč o domenu govornog i jezičkog funkcionisanja, literatura o motoričkim poremećajima govora u ovoj populaciji je obimna. Kod PB dominira hipokinetička dizartrija, koja se ispoljava izmenjenim obrascem respiracije, hipernazalnošću, nepreciznošću pri artikulaciji konsonanata i vokala, monotonim glasom, smanjenim intezitetom govora, palilalijom, nevoljnim pauzama u govoru i dr. (Yang et al, 2020). Pored dizartrije, kao upadljivog govornog poremećaja, osobe sa PB ispoljavaju deficite različitih aspekata jezika.…”