Mean Contact Quotient Using Electroglottography in Patients With Multiple Sclerosis *Bassem Yamout, †Zaid Al-Zaghal, †Iyad El-Dahouk, ‡Sahar Farhat, §Abla Sibai, and †Abdul-Latif H. Hamdan, *yzxBeirut, Lebanon Summary: Objective. To compare the mean and standard deviation (SD) of the contact quotient (CQ) of the sustained vowels ([a] and [e]) in multiple sclerosis (MS) patients versus controls. Study Design. Cross-sectional study. Materials and Methods. Thirty-nine subjects (24 patients and 15 controls) participated in this study. Laryngeal electroglottography was performed on all subjects while phonating the vowels [a] and [e] at a comfortable pitch and loudness. The fundamental frequency, mean CQ, SDs, and jitter were computed for both vocal tasks. Results. The mean age of the MS group was 36.25 + 10.61 years. All laryngeal examinations were normal and five patients with MS had dysphonia described as voice breaks and fatigue in connected speech. For both vowels [a] and [e], the mean closed quotients were comparable in groups, MS and control (43.90 vs 53 for [a] and 44.75 vs 43.63 for [e]) with no significant difference. When comparing five MS patients with dysphonia versus con- trols, for the vowel [a], the mean closed quotient was significantly lower in MS patients with dysphonia (P values of 0.043). Conclusion. The mean closed quotient for sustained vowels [a] and [e] are comparable in MS patients and healthy controls except in patients with dysphonia. Key Words: Contact quotient–Electroglottography–Multiple sclerosis. INTRODUCTION Multiple Sclerosis (MS) is an autoimmune inflammatory disor- der that affects various parts of the central nervous system. The disease was first described in 1868 by Charcot 1 as a chronic de- generative neurologic disorder that results in demyelination and loss of conductive properties of axons within the brain and spi- nal cord. Women are affected more than men and the prevalence rate ranges from 2 to 150 per 100 000 with varying geographic distribution. 2,3 Several etiologic factors have been implicated and these include genetic, infectious, and environmental. As a result of the widespread involvement of the nervous sys- tem, MS has a wide range of neurologic manifestations with motor, sensory, and cognitive impairments. The most common symptoms attributed to MS are optic neuritis, nystagmus, tremors, gait instability, sexual and bladder incontinence, scanning speech, and last but not the least phonatory instabilities. The ‘‘scanning speech’’ or dysarthria of MS is predominantly mixed with both an ataxic and a spastic component to it. 4,5 Phonatory disturbances on the other hand span a large array of symptoms ranging from impairments of loudness control, pitch control, voice breaks, harshness, hypernasality, and breathiness. 6–9 Despite the fact that dysarthria and phonatory symptoms have been reported in more than 50% of MS patients, research on dys- phonia in association with this disease remains scarce. 4,5,10–12 Very few studies have discussed the phonatory symptoms in MS patients using objective measures. 6–9,13,14 Many of these were based on the self-reported questionnaires and perceptual evaluation with less focus on acoustic analysis and particularly on electroglottography (EGG) as a descriptive tool. 7,9 The contact quotient (CQ), an outcome measure of EGG, is an important indicator of vocal folds closure during phonation. It provides an indirect and noninvasive measure of the closure pattern by reflecting the amount of transverse impedance across the glottis. A decrease in the mean closed quotient would suggest a glot- tic insufficiency with an increase in the mean flow rate, whereas an increase in the mean closed quotient would suggest a hyper- functional glottic behavior. Organic lesions of the vocal fold re- sulting in an increase in the closing phase are associated with an elevated closed quotient, whereas bowing of the vocal folds with glottic insufficiency is associated with a reduced closed quotient. 15–17 Konstantopoulos et al 6 was the only one to use EGG as an ob- jective voice analysis tools to investigate the vocal fold closure in MS patients. In his investigation, the EGG parameters used were vocal jitter, mean fundamental frequency, and standard deviation (SD) of the average fundamental frequency. The re- sults indicated that these vocal parameters differentiated the MS group from controls, but there was no mentioning of the mean CQ. The purpose of this study is to make a comparative analysis of the mean and SD of the CQ of the sustained vowels [a] and [e] in MS patients versus controls. The fundamental frequency, SD, and jitter will also be reported. MATERIALS AND METHODS A total of 39 subjects were asked to participate in this study af- ter having read and signed the informed consent approved by Accepted for publication October 31, 2012. No conflict of interest or financial support in relation to this manuscript. The research received no specific grant from any funding agency in the public, commer- cial, or not-for-profit sectors. From the *Department of Neurology, American University of Beirut Medical Center, Beirut, Lebanon; yDepartment of Otolaryngology–Head and Neck Surgery, American University of Beirut Medical Center, Beirut, Lebanon; zDepartment of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon; and the xDepartment of Epidemiology and Population Health, American University of Beirut, Beirut, Lebanon. Address correspondence and reprint requests to Abdul-Latif H. Hamdan, Department of Otolaryngology–Head and Neck Surgery, American University of Beirut, PO Box 11-0236, Beirut, Lebanon. E-mail: ah77@aub.edu.lb Journal of Voice, Vol. 27, No. 4, pp. 506-511 0892-1997/$36.00 Ó 2013 The Voice Foundation http://dx.doi.org/10.1016/j.jvoice.2012.10.016