LARYNGEAL AND PHONATORY DYSFUNCTION IN PARKINSONS-DISEASE

The vocal function of 20 speech-disordered subjects with idiopathic Pa rkinson's disease (PD) was assessed using both perceptual and instrume ntal techniques. The instrumental analysis included electroglottograph y and the use of a computerized airflow/air pressure analysis system ( Aerophone II). Variables measured included parameters of the Lx wavefo rm (F-0, duty cycle, and closing time) as well as aerodynamic paramete rs such as subglottal pressure, laryngeal airway resistance, average p honatory sound pressure level, phonatory flow rate and ad/abduction ra te. Values were compared to those recorded from a group of non-neurolo gically impaired controls matched for age and sex. Perceptual assessme nt revealed that 89.5% of the PD subjects exhibited deviant laryngeal features. None of the electroglottography (EGG) parameters differed si gnificantly between the PD and control groups. However four of the fiv e aerophone parameters did differentiate between the two subject group s. The PD group was characterized by higher levels of glottal resistan ce than the control subjects and lower values for subglottal pressure, average phonatory sound pressure level and phonatory how rate. A clus ter analysis based on the EGG and aerodynamic measures identified the presence of four subgroups, two which represented different expression s of hyperfunction of the larynx within the PD group. The results are discussed with reference to the expected effects of PD on vocal functi on.