The Effects of Participation in a Group Music Therapy Voice Protocol (G-MTVP) on the Speech of Individuals with Parkinson's Disease

Over one million Americans are currently living with Parkinson's disease (PD), a degenerative neurological disorder caused by decreased dopamine in the substantia nigra (National Parkinson Foundation, 2010). Although PD is typically characterized by motor symptoms, impaired speech is a non-motor symptom experienced by many individuals with PD. According to recent estimates, approximately half of the population of individuals with PD has at least moderate speech impairments (Ho, lansek, Marigliani, Bradshaw, & Gates, 1998). Hypokinetic dysarthria is the term used to describe the voice and speech abnormalities associated with PD, which include reduced loudness or hypophonia, reduced prosodie pitch inflection, or monotone speech, hoarse voice, and imprecise articulation (Ramig, Fox, & Sapir, 2004). A study by Fox and Ramig (1997) on characteristics of speech impairment in individuals with PD found that individuals with PD tended to speak more softly (by 2 to 4 decibels) and had less intelligible speech than healthy controls.Perception of loudness is also affected by PD. Ho, Bradshaw, and lansek (2000) observed that people with PD tended to overestimate how loudly they were speaking to a greater degree than healthy controls. This difficulty with perception of loudness may lead many individuals with PD to deny that their speech is impaired. Instead, they may complain that others around them have impaired hearing, since they perceive their own speech as being adequately loud. Other speech characteristics of persons with PD may include higher frequency perturbation or "jitter," lower harmonic/noise ratio, lower frequency and intensity variability, lower phonational range, voice arrests, and struggle while speaking (Gamboa et al., 1997).Treatment for Speech Impairments in Individuals with PDSpeech therapy has been shown to be the most effective treatment for speech impairments resulting from PD. The Lee Silverman Voice Treatment (LSVT) program has received the greatest amount of attention in the research literature on speech treatments for individuals with PD (Spielman, Ramig, Mahler, Halpern, & Gavin, 2007). LSVT is used in over 30 countries to treat speech disorders in individuals with PD, and has been cited as highly effective in improving the loudness and clarity of speech of those affected by PD (Spielman et al., 2007). LSVT focuses on disordered voice, rather than articulation or rate of speech, by promoting increased phonatory effort, which increases amplitude (loudness). The treatment is based on five concepts which address the problems of decreased amplitude, decreased sensory perception of effort, and difficulty generating the right amount of effort to produce loud speech. The five concepts are: (a) focus on voice; (b) improve sensory perception of effort; (c) administer high effort treatment; (d) treat intensively; and (e) quantify treatment-related changes (Ramig et al., 2004).LSVT typically includes exercises to increase vocal fold adduction, such as pressing down on the arms of a chair while vocalizing, and drills to provide practice in sustaining maximum duration phonation and maximum fundamental frequency range. It also includes the application of LSVT principles when reading aloud and participating in conversation. The instruction "think loud" is used as a cue throughout treatment, and a decibel meter or another type of acoustic feedback mechanism is often used to provide the individual with feedback on their intensity level (Ramig, Countryman, Thompson, & Horii, 1995). In an LSVT session, an individual may be asked to practice maintaining the vowel /a/ for as long as they can, while monitoring their intensity and trying to keep it above a certain set decibel level. They may then be asked to read a passage out loud and continue to monitor their intensity. Drills geared toward increasing maximum fundamental frequency range may involve producing the lowest pitch possible and gliding up to the highest pitch possible. …