ABSTRACT
INTRODUCTION Nearly 90% of individuals with Parkinson’s disease (PD) develop voice and speech disorders during the course of their disease (1,2). These disorders are characterized by reduced voice volume (hypophonia); a breathy, hoarse, or harsh voice quality (dysphonia); imprecise consonant and vowel articulation due to reduced range of articulatory movements (hypokinetic articulation) and a tendency of these movements to decay and/or accelerate toward the end of a sentence; reduced voice pitch inflections (hypoprosodia, monotone); and rushed, dysfluent, hesitant, or stutteredlike speech (palilalia). Collectively, these disorders have been termed hypokinetic dysarthria (3). They may be among the first signs of PD, with hypophonia and dysphonia typically preceding articulation, prosodic and fluency disorders (1,2,4). Hypokinetic dysarthria in individuals with PD typically results in reduced speech intelligibility. Reduced facial expression (hypomimia) is also common in individuals with PD. Together, these can be interpreted as a person being cold, withdrawn, unintelligent, and moody (5,6). These factors may also impair the ability to socialize, convey important medical information, interact with family members, and maintain employment (5).
