Vocal Deficits Research Articles

Transoral laser ventricular fold resection and thyroarytenoid myoneurectomy for adductor spasmodic dysphonia: Long‐term outcome

A transoral approach to laser myoneurectomy of the thyroarytenoid muscles was recently reported as an effective technique for treatment of adductor spasmodic dysphonia (ASD). The short-term results were encouraging. In this study, a long-term surgical outcome of this technique is investigated. A prospective clinical series. Fifty-two patients with ASD underwent transoral laryngomicrosurgery with a CO(2) laser to resect the ventricular folds followed by myoneurectomy of the thyroarytenoid muscles. The nerve fibers of recurrent laryngeal nerve terminating at the thyroarytenoid muscle, which were frequently found branching deeply among the posterior belly of this muscle, were vaporized. Care was taken not to damage the vocal ligaments, lateral cricoarytenoid muscles, or arytenoid cartilages. Pre- and postoperative subjective voice assessments, and acoustic and aerodynamic measurements, were performed and statistically analyzed. Twenty-nine of the 52 patients who were followed up for more than 12 months (range, 12-63 months; mean, 31 months) were studied. Moderate and marked vocal improvement was achieved in 90% (26/29) of the patients. Three patients had 30% improvement, which was reported as unsuccessful. Eight of the 26 patients who were satisfied with their postoperative voice still had a mild strain during phonation. Of the eight patients, seven achieved normal or nearly normal voice quality after revision laser surgery. No significant vocal deficit or paralysis was observed in any patient. After long-term follow-up of 31 months on average, approximately 90% of the ASD patients obtained moderate to marked improvement of vocal performance after transoral laser surgery. The long-lasting outcome is encouraging.

Marsupialisation and strap muscle transposition laryngoplasty for vocal cysts with vocal fold atrophy

Vocal cysts with fold atrophy often result in more severe glottal incompetence than vocal cysts along during phonation. Although total excision or marsupialisation are reliable treatments for vocal fold cysts, any post-operative vocal deficit with significant glottal gap will need further treatment. This study aimed to evaluate the efficacy of combined treatment consisting of marsupialisation of the cyst immediately followed by strap muscle transposition laryngoplasty. Under direct laryngomicroscopy, microscissors were used to make a disc-shaped incision encircling the equator of the cyst. After marsupialisation of the cyst, a simultaneous medialisation laryngoplasty with strap muscle transposition was performed. Seven patients with vocal cysts and marked vocal fold atrophy were included in the study. After surgery, subjective improvement in voice quality was reported by all patients. Patients' glottal incompetence and vocal performance were markedly improved. Marsupialisation is a simple and effective surgical technique for vocal fold cysts. For cases of vocal cysts with marked vocal fold atrophy, marsupialisation followed by medialisation laryngoplasty with strap muscle transposition may be considered.

Reduction of dopamine synaptic activity: Degradation of 50-khz ultrasonic vocalization in rats.

Vocal deficits are prevalent and debilitating in Parkinson's disease. These deficits may be related to the initial pathology of the nigrostriatal dopamine neurons and resulting dopamine depletion, which contributes to dysfunction of fine motor control in multiple functions. Although vocalization in animals and humans may differ in many respects, we evaluated complex (50-kHz) ultrasonic mate calls in 2 rat models of Parkinson's disease, including unilateral infusions of 6-hydroxydopamine to the medial forebrain bundle and peripheral administration of a nonakinesia dose of the dopamine antagonist haloperidol. We examined the effects of these treatments on multiple aspects of the acoustic signal. The number of trill-like (frequency modulated) 50-kHz calls was significantly reduced, and appeared to be replaced by simpler (flat) calls. The bandwidth and maximum intensity of simple and frequency-modulated calls were significantly decreased, but call duration was not. Our findings suggest that the nigrostriatal dopamine pathway is involved to some extent in fine sensorimotor function that includes USV production and complexity.

Aerodynamic Measurements in Medialization Thyroplasty

Objective --External vocal fold medialization thyroplasty is a standard technique for improving voice, swallowing and breathing impairments due to insufficient glottal closure caused by either unilateral vocal fold paralysis or deficit of vocal fold tissue (i.e. as a result of cordectomy, scarring processes or sulcus glottidis). However, only scant information is available concerning the effect of the medialization thyroplasty on aerodynamic parameters. The aim of this study was to investigate the effect of vocal fold medialization thyroplasty on the degree of laryngeal stenosis using selected aerodynamic parameters. Material and Methods --Thirty patients (12 female, 18 male) underwent external vocal fold medialization with a titanium vocal fold medialization implant under local anesthesia supplemented by i.v. sedation. Pulmonary function tests were performed pre- and postoperatively and selected parameters were analyzed statistically. Results --All patients reported improved self-control of breathing during speaking, laughing, coughing and physical activity. The postoperative values of the parameters tested showed no significant alteration in comparison to the preoperative data. Conclusions --The analysis of the aerodynamic findings indicated that the medialization procedure using an implant did not cause an increase in the laryngeal resistance.

Female preference for the songs of older males and the maintenance of dialects in brown-headed cowbirds (Molothrus ater)

Female preferences for local song types have been implicated in the maintenance of local song dialects in songbirds. Such preferences can be assessed by copulation solicitation displays (CSDs) of females in response to playback of male songs. We used CSDs to determine if female brown-headed cowbirds (Molothrus ater) in the Sierra Nevada of California discriminate between yearling and adult male vocalizations based on two vocal characteristics that often distinguish songs of these age classes, incomplete renditions of the local dialect flight whistle and 'unique', unshared perched song types. We predicted stronger responses to adult songs because yearlings are rarely involved in copulations observed in these dialects although they are sexually mature. Eleven estradiol-treated females trapped in the Convict flight whistle dialect were more sexually stimulated by complete Convict flight whistles recorded from either adults or yearlings than by incomplete flight whistles typical of yearlings. Females also found the shared perched song types of local adults more stimulating than the 'unique' types of yearlings. These sexual preferences for complete and appropriate local songs are consistent with the hypothesis that females use vocal differences between the age classes as cues in their choice of adults as mates. Furthermore these preferences would create selection pressure on young males to conform to the local song culture. Mainly because of a learning constraint in their hatching year, yearlings do not complete their development of local repertoires until the start of their second season when they are two years old. The vocal deficits of yearling males serve as uncheatable indicators of age, and age in turn is a likely correlate of male genetic quality, which may explain female preference for songs that reliably identify older males. This system shows that signal honesty can be maintained by developmental constraints rather than by high signal cost alone.