A new study defines the baseline level of laryngeal function in patients with advanced Parkinson's disease prior to neurosurgical treatment.
Parkinson's is a common neurologic disorder, with more than 70 percent of patients reporting problems with speech and voice. While medical treatments are only partially effective for those in the advanced stages, surgical procedures, such as deep brain stimulation (DBS), are effective in improving patient symptomology.
Voice and speech outcomes after DBS have not been evaluated. The new study confirmed laryngeal deficits in patients with advanced Parkinson's disease who are considering surgical therapy. Common findings include high self-reported voice handicap, moderate or severe vocal fold bowing, and pharyngeal swallowing deficits. This set of pilot data will act as a baseline for patients after their neurosurgical procedure.
Parkinson's is a progressive neurodegenerative disorder that results from a decline in the release of dopamine within the striatial tracts of the basal ganglia. It affects approximately 1 million Americans. Symptoms include bradykinesia, muscle rigidity, tremor and postural instability. The majority of patients with Parkinson's also have voice problems characterized by vocal tremor, decreased volume and hoarseness.
Treatment for Parkinson's hypophonia can target the larynx and voice, or it can be more general and treat global symptoms. The disease itself commonly is treated with medicines such as anticholinergics, dopamine agonists; dopamine replacement and MAO-B inhibitors. Studies specifically have looked at voice improvement with medicines alone and have shown improvements in vocal intensity and speech duration concurrent to improvements in body symptoms.
Currently, deep brain stimulation is being offered to patients whose disease is recalcitrant to medical therapy but who are in otherwise relative good health. DBS has emerged as an attractive alternative to the ablative procedures by creation of a functional lesion. In this procedure an electrode is implanted in the globus pallidus using stereotactic technique. The electrode is connected to a stimulator that lies in a subcutaneous pocket in the patient's chest, similar to a cardiac pacemaker.
After a healing period the stimulator is turned on, and the patient sustains a functional and adjustable lesion within the pallidum. Rigidity, tremor, bradykinesia, gait and L-dopa effectiveness are improved. Complications are minimized. If ineffective, patients still can be candidates for other surgical therapy, unlike those who undergo pallidotomy.
No study to date has looked at the laryngeal and vocal outcomes in patients who have undergone DBS. The recent study set out to obtain pilot data regarding the laryngeal findings in patients with advanced Parkinson's seeking surgical treatments for their symptoms.
The study, titled "Laryngeal Findings in Advanced Parkinson's Disease," was conducted by Joel Blumin, MD; Dana Pcolinsky, MS, CCC-SLP; and Joseph Atkins, MD, from the Penn Center for Voice, Pennsylvania Hospital, and the Department of Otorhinolaryngology-Head & Neck Surgery, at the University of Pennsylvania in Philadelphia. They presented their findings at the American Laryngological Association meeting last month in Nashville, TN.
The study involved patients who were considering DBS therapy. They were referred for multidisciplinary evaluations so baseline physical and psychological function could be obtained. Part of the evaluation included examination of the larynx and speech and swallow function. Fifteen patients with advanced Parkinson's disease (stage III or worse) were evaluated.
All of the patients underwent a videostroboscopy and fiberoptic endoscopic evaluation of swallowing (FEES). They were asked to phonate /i/ at a comfortable volume and pitch and then increase their volume and alter the pitch. Audio and video data later were played back for evaluation by the authors. The data were evaluated for vocal tremor, glottic configuration and movement, bowing of vocal folds, and other lesions. Vocal fold bowing was defined as persistent opening of the middle third of the membranous glottis and scaled as absent, mild, moderate or severe.
FEES was performed just after the phonatory evaluation. A flexible nasopharyngoscope was passed transnasally, allowing visualization of the pharynx and larynx during swallowing tasks. The patient was asked to swallow three consistencies of food: puree (applesauce), solid (cracker), and liquid (water). The studies later were evaluated for swallow initiation delay, quality of bolus propagation, pharyngeal movement, laryngeal penetration or aspiration, and remaining residue or pooling.
Voice handicap was determined with a self-assessment instrument, a 30-item test with 10 questions in three categories: emotional, physical and functional. Patients were asked to answer each question with an ordinal on a five-point scale (with 0 representing "no disability" and 4 indicating "severe disability"). Additionally, during the examination, patients were asked to identify what issues specifically bother them with respect to their voice.
Most of the patients identified gait impairment or bradykinesia as the most important symptom that led them to seek out surgical care for their disease. Although almost all patients identified a problem with voice and swallowing, only a few thought of these issues as driving forces to seek out surgical care.
Review of the stroboscopic data showed bowing in 86.7 percent of patients with varying severity. Eight patients (53 percent) had vocal tremor as noted by tremulous movements of the laryngopharynx during phonation, and one patient had severe upper body dyskinesia with mass movements of the entire neck and torso. None of the patients had any evidence of mass lesion or other process. Many had findings consistent with mild laryngopharyngeal reflux. Two patients were noted to have pathology that otherwise could affect voice and swallowing, and one had a unilateral vocal cord paralysis with good contralateral compensation that previously was undiagnosed.
FEES testing showed uniform results. Thirteen patients (86.7 percent) had some degree of pharyngeal phase deficit with no evidence of penetration or aspiration. No patient had severe oral or esophageal deficits. All patients with pharyngeal phase deficit exhibited varying degrees of residue to puree or solid consistencies after swallowing. The majority (73.3 percent) had only mild residue noted.
Vocal fold bowing is a consistent laryngeal finding in patients with Parkinson's. In this study 87 percent of patients had this finding, with many demonstrating bowing that separates the folds enough so that vocal fold entrainment effectively is decreased. Self-reported voice handicap was high in the patient population, likely reflecting the status of their advanced disease and highlighting the significance they place in the loss of effective voice. VHI scores were even greater then self-reported handicap in unilateral vocal fold paralysis.
The FEES evaluation may be somewhat limited in completely evaluating oral phase deficits, but it is useful for gauging whether patients have issues that can preclude them to penetration or aspiration, which is important in this subset of patients undergoing a neurosurgical procedure.