Massimiliano Todisco1, Enrico Alfonsi2, Ioannis Ugo Isaias3, Roberta Zangaglia4, Brigida Minafra4, Giuseppe Cosentino5, Michele Terzaghi6, Nicoló Gabriele Pozzi7, Raffaele Manni6, Claudio Pacchetti4. 1. Parkinson's Disease and Movement Disorders Unit, IRCCS Mondino Foundation, Pavia, Italy; Department of Neurophysiopathology, IRCCS Mondino Foundation, Pavia, Italy. 2. Department of Neurophysiopathology, IRCCS Mondino Foundation, Pavia, Italy. Electronic address: enrico.alfonsi@mondino.it. 3. Department of Neurology, University Hospital Würzburg and Julius Maximilian University of Würzburg, Würzburg, Germany. 4. Parkinson's Disease and Movement Disorders Unit, IRCCS Mondino Foundation, Pavia, Italy. 5. Department of Neurophysiopathology, IRCCS Mondino Foundation, Pavia, Italy. 6. Sleep Medicine and Epilepsy Unit, IRCCS Mondino Foundation, Pavia, Italy. 7. Parkinson's Disease and Movement Disorders Unit, IRCCS Mondino Foundation, Pavia, Italy; Department of Neurology, University Hospital Würzburg and Julius Maximilian University of Würzburg, Würzburg, Germany.
Abstract
INTRODUCTION: Multiple system atrophy (MSA) is a neurodegenerative disorder characterized by dysautonomia in combination with parkinsonian and cerebellar signs. Stridor may also occur and it is associated with life-threatening events and poor prognosis. The pathophysiology of stridor in MSA is still debated. OBJECTIVE: To define correlations between diurnal electromyographic (EMG) abnormalities of vocal cord muscles and stridor in MSA phenotypes. METHODS: We recruited 60 patients with "probable" MSA (45 with parkinsonian [MSA-P] and 15 with cerebellar phenotype [MSA-C]). Nocturnal stridor was detected with video-polysomnography, whereas diurnal stridor was clinically noted when present. A diurnal kinesiologic EMG study of the adductor thyroarytenoid and the abductor posterior cricoarytenoid muscles was also performed. RESULTS: Among subjects with nocturnal stridor, MSA-P patients predominantly showed a paradoxical burst-like activation of the adductor thyroarytenoid muscle during inspiration. This dystonic pattern was associated with nocturnal stridor in MSA-P (odds ratio [OR] = 23.64, 95% confidence interval [CI] 3.42-70.77, p < 0.001). Conversely, MSA-C patients with nocturnal stridor mainly had additional neurogenic findings of vocal cord muscles. This dystonic-plus pattern correlated with nocturnal stridor in MSA-C (OR = 17.21, 95% CI 4.17-74.92, p < 0.01). The findings of diurnal stridor paralleled the observations for nocturnal stridor. CONCLUSIONS: The pathophysiology of stridor may differ between MSA phenotypes, possibly related to dysfunctional supranuclear mechanisms in MSA-P (dystonic pattern) and to additional nuclear damage in MSA-C (dystonic-plus pattern).
INTRODUCTION:Multiple system atrophy (MSA) is a neurodegenerative disorder characterized by dysautonomia in combination with parkinsonian and cerebellar signs. Stridor may also occur and it is associated with life-threatening events and poor prognosis. The pathophysiology of stridor in MSA is still debated. OBJECTIVE: To define correlations between diurnal electromyographic (EMG) abnormalities of vocal cord muscles and stridor in MSA phenotypes. METHODS: We recruited 60 patients with "probable" MSA (45 with parkinsonian [MSA-P] and 15 with cerebellar phenotype [MSA-C]). Nocturnal stridor was detected with video-polysomnography, whereas diurnal stridor was clinically noted when present. A diurnal kinesiologic EMG study of the adductor thyroarytenoid and the abductor posterior cricoarytenoid muscles was also performed. RESULTS: Among subjects with nocturnal stridor, MSA-Ppatients predominantly showed a paradoxical burst-like activation of the adductor thyroarytenoid muscle during inspiration. This dystonic pattern was associated with nocturnal stridor in MSA-P (odds ratio [OR] = 23.64, 95% confidence interval [CI] 3.42-70.77, p < 0.001). Conversely, MSA-C patients with nocturnal stridor mainly had additional neurogenic findings of vocal cord muscles. This dystonic-plus pattern correlated with nocturnal stridor in MSA-C (OR = 17.21, 95% CI 4.17-74.92, p < 0.01). The findings of diurnal stridor paralleled the observations for nocturnal stridor. CONCLUSIONS: The pathophysiology of stridor may differ between MSA phenotypes, possibly related to dysfunctional supranuclear mechanisms in MSA-P (dystonic pattern) and to additional nuclear damage in MSA-C (dystonic-plus pattern).