Parkinson Disease Jaime Moore (bio) and Jessica Kandl (bio) CARE OF THE PROFESSIONAL VOICE Parkinson disease (PD) is a progressive neurological disorder that affects approximately two million Americans.1 Typically, this disease presents in either sex after the age of 60; however, it can present in individuals as young as 30. It is the second most common neurodegenerative disorder facing the elderly.2 In addition to affecting movement, 70–90% of patients also experience Parkinson-related voice and speech disturbance, and up to 1/3 of these patients identify the voice and speech symptoms as the most debilitating deficits related to the disease.3 Parkinson disease can be challenging in singers and it is imperative that singing teachers and professional voice users recognize the effects of PD on the voice and speech and be familiar with treatment options. WHAT IS PARKINSON DISEASE? Parkinson disease is a neurologic disease caused by death of neurons in the substantia nigra, a dopamine-producing region of the brain.4 Subsequently, there is a decrease in production of dopamine, an important neurotransmitter. The substantia nigra is part of the basal ganglia, a region of the brain crucial in movement; therefore, changes in the neurotransmitters in this region lead to motor impairment, including difficulty walking resting, speech and voice impairment, tremor, rigidity (stiffness), and bradykinesia (slow movements). In addition to motor symptoms, the disease can cause depression, sleep disturbance, voice changes, and possibly cognitive impairments. Voice changes can be the first sign of PD, and recognizing these changes is important in ensuring that the patient receives the necessary care.5 Parkinson disease should be distinguished from the Parkinson Plus Syndromes such as multisystem atrophy.6 This group of syndromes is defined by Parkinson symptoms, but with additional clinic features such as rapid progression, early dementia, vision changes, and frequent falls. Vocal and speech disturbances in PD include hypokinetic dysarthrias marked by monopitch and slowed speech, reduced stress, imprecise consonants, breathiness, and reduced loudness.7 Patients with PD also have abnormal vocal processing and auditory feedback, which leads to the patient perceiving the voice as normal when it is not.8 Singers might note loss of range, decreased loudness, prolonged warm-up, and increased vocal instability. These speech and voice changes can limit patients’ ability to convey emotions as well as decrease speech intelligibility.9 Decreased intelligibility can lead patients with Parkinson disease to limit social interaction, which may result in isolation and decreased quality of life. [End Page 609] EVALUATION Patients diagnosed with Parkinson dysphonia and/or dysarthria require a multidisciplinary team approach including evaluations by a neurologist, otolaryngologist, speech language pathologist, and other professionals. A complete head and neck exam should be conducted, and additional neurologic signs such as resting tremor, “pill rolling” finger movements, and decreased facial expression should be noted.10 As part of the evaluation, the larynx is visualized typically using videostrobolaryngoscopy. Vocal fold bowing and atrophy are seen commonly, and the vocal fold bowing is associated with glottal incompetence and compensatory muscle tension dysphonia.11 Vocal tremor and vocal paresis and paralysis also have been reported in these patients. Objective voice testing can demonstrate increased shimmer and jitter and decreased harmonic-to-noise ratio. In addition to voice complaints, patients often have difficulty swallowing and reduced sense of smell, and these symptoms may require additional evaluation.12 TREATMENT Typically, medical therapy to increase dopamine is the initial treatment for PD.13 This is done through a combination of medications that prevent degradation of dopamine and increase the supply of dopamine. The regimen requires adjustment as the disease progresses. These medications have been shown to improve motor symptoms of the disease like rigidity, bradykinesia, and resting tremor; however, there are mixed data about the vocal impact.14 Deep brain stimulation (DBS) is another treatment option that involves implanting electrodes into specific areas of the brain. These electrodes send electrical impulses that help regulate pathway activity in a more normal pattern. This treatment has been shown to dramatically improve overall motor function of the patient; however, the vocal results are variable, with some studies demonstrate a negative impact on vocal quality.15 As neither option specifically addresses Parkinson dysphonia, additional treatment typically...
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Nov 1, 2024
Josef Finsterer 
Open Access