The effects of surface electrical stimulation on neck muscles in voicing and swallowing

Abstract

Numerous studies have been reported on the therapeutic effectiveness of surface electrical stimulation (ES) in voicing and swallowing (Bulow, Speyer, Baijens, Woisard & Ekberg, 2008; Ludlow, Humbery, Saxon, Poletto, Sonies & Crujido, 2007). However, controversial agrument on its effectiveness is still ongoing. Humbert and colleagues (2007) found the use of surface ES only facilitated vocal fold closure to a small degree in healthy adults. Some studies reported that laryngeal elevation was facilitated in dysphagic patients (Bulow et al., 2008; Shaw, Sechtem, Searl, Keller, Rawi & Dowdy, 2007) while others found lowering of larynx position during the use of surface ES (Humbert, Poletto, Saxon, Kearney, Crujido, Wright-Harp et al., 2006; Ludlow et al., 2007). In this study, the effects of surface ES on laryngeal movement during voicing and swallowing were investigated in 15 normal healthy individuals and 5 individuals with unilateral vocal fold paralysis. Surface ES was given over the extrinsic laryngeal muscles to determine if the laryngeal movement would be altered. According to the International Classification of Functioning, Disability and Health (ICF) framework (World Health Organization, 2001), assessments on i) acoustic, perceptual and aerodynamic aspects of voice quality; ii) voice range profile; iii) laryngeal imaging; iv) swallowing ability; and v) larynx position are used at the impairment level. Measurements of functional impacts included the Voice Activity and Participation Profile (VAPP) (Ma & Yiu, 2001) and the M.D. Anderson Dysphagia Inventory (MDADI) (Chen, Frankowski, Bishop-Leone, Hebery, Leyk, Lewin & Goepfert, 2001). Each subject received one-hour surface ES once a week for five consecutive weeks. Prelimary data revealed that the application of surface ES facilitated the laryngeal movement and the laryngeal position during voicing and swallowing.