Arytenoid cartilage movements are hypokinetic in Parkinson’s disease: A quantitative dynamic computerised tomographic study

Abstract

BackgroundVoice change is one of the earliest features of Parkinson’s disease. However, quantitative studies of vocal fold dynamics which are needed to provide insight into disease biology, aid diagnosis, or track progression, are few.MethodsWe therefore quantified arytenoid cartilage movements and glottic area during repeated phonation in 15 patients with Parkinson’s disease (symptom duration < 6 years) and 19 controls, with 320-slice computerised tomography (CT). We related these measures to perceptual voice evaluations and spirometry. We hypothesised that Parkinson’s disease patients have a smaller inter-arytenoid distance, a preserved or larger glottic area because vocal cord bowing has previously been reported, less variability in loudness, more voice dysdiadochokinesis and breathiness and a shortened phonation time because of arytenoid hypokinesis relative to glottic area.ResultsInter-arytenoid distance in Parkinson’s disease patients was moderately smaller (Mdn = 0.106, IQR = 0.091–0.116) than in controls (Mdn = 0.132, IQR = 0.116–0.166) (W = 212, P = 0.015, r = −0.42), normalised for anatomical and other inter-subject variance, analysed with two-tailed Wilcoxon’s rank sum test. This finding was confirmed in a linear mixed model analysis—Parkinson’s disease significantly predicted a reduction in the dependent variable, inter-arytenoid distance (b = −0.87, SEb = 0.39, 95% CI [−1.66, −0.08], t(31) = −2.24, P = 0.032). There was no difference in glottic area. On perceptual voice evaluation, patients had more breathiness and dysdiadochokinesis, a shorter maximum phonation time, and less variability in loudness than controls. There was no difference in spirometry after adjustment for smoking history.ConclusionsAs predicted, vocal fold adduction movements are reduced in Parkinson’s disease on repeated phonation but glottic area is maintained. Some perceptual characteristics of Parkinsonian speech reflect these changes. We are the first to use 320-slice CT to study laryngeal motion. Our findings indicate how Parkinson’s disease affects intrinsic laryngeal muscle position and excursion.

Radiological correlates of vocal fold bowing as markers of Parkinson’s disease progression: A cross-sectional study utilizing dynamic laryngeal CT

“…We previously studied 19 healthy controls and 15 pwPD. Those patients had a disease duration less than 6 years and modified Hoehn and Yahr (H&Y) stage of 2.5 or lower [10]. We expanded this cohort by recruiting patients with more advanced PD from the Movement Disorders Clinic at Monash Medical Centre.…”

“…Statistical tests utilised the mean GA and IAD (analogous to our previously reported key measures AUC ga and AUC iai respectively) [10], effective minimum GA and IAD, mean IAI and av �! , and the effective maximum IAI, av �!…”

“…Laryngeal computed tomography (CT) is a potential technique to study these voice changes. Our previous study [10] used laryngeal CT during vocalization to measure glottic area (GA) and arytenoid cartilage position. It found differences in the inter-arytenoid distance (IAD) between patients with early PD and healthy controls.…”

Spatial Motion of Arytenoid Cartilage Using Dynamic Computed Tomography Combined with Euler Angles

“…Energy spectrum CT (GE's Revolution CT 256-Slice Scanner) is an instrumental tool which offers temporal and spatial resolution superior to typical CT and can noninvasively obtain dynamic sequence images of subjects in different laryngeal functional states. [1][2][3] The Euler angles are three angles to describe the orientation of a rigid body with respect to a fixed coordinate system. The movement of the arytenoid cartilage relative to the cricoid cartilage is similar to the aircraft to the earth.…”

“…Ideally, the motion of laryngeal structures such as the arytenoid cartilage should be captured by objective measurement in vivo and in real time. Energy spectrum CT (GE's Revolution CT 256‐Slice Scanner) is an instrumental tool which offers temporal and spatial resolution superior to typical CT and can non‐invasively obtain dynamic sequence images of subjects in different laryngeal functional states …”