Roger C. Lindeman

Neocortical and limbic lesion effects on primate phonation.

Abstract Five monkeys were individually trained to emit a relatively prolonged call of specified loudness in order to obtain a preferred food. At the completion of training each animal gave the required call in response to a signal cue light and withheld calls during periods in which no cue light was present. Sequential bilateral removal of the homolog of Brocas area, transitional parieto-occipital cortex, and temporal association cortex in 3 monkeys had no influence on performance of the discriminative call. There was no change in sound spectral properties of the call as a result of surgery. Bilateral removal of anterior cingulate/subcallosal gyrus in the remaining two monkeys was accompanied by loss of phonatory performance. Postoperative calls given by each of these animals in the test situation were weak and infrequent. The data indicate that control over learned, discriminative phonation in monkeys is not mediated by neorcortical regions homologous to human ‘speech’ areas.

Clinical experience with the tracheoesophageal anastomosis for intractable aspiration.

Clinical experience in six patients in whom the tracheoesophageal diversion procedure or a modification thereof has been performed is presented. Two of these patients have been reconstructed with resulting normal laryngeal and esophageal function. Three of the patients have successfully undergone tracheoesophageal anastomosis and are candidates for reconstruction. One patient in whom the tracheoesophageal anastomosis has been present for 2K years may never demonstrate neurological return sufficient for reversal of the procedure. On the basis of these six cases, we consider the tracheoesophageal anastomosis to be an effective, yet reversible, procedure for intractable aspiration.

Vocalization in rhesus monkeys: Conditionability

Three rhesus monkeys were individually trained to emit relatively prolonged calls in an experimental arrangement which required that intensity of each call be maintained within prescribed limits. Each animal learned to produce the calls when a stimulus signaled the appropriate occasion. Stimulus control over the calls was demonstrated by increased number of calls and increased average duration of calls when the signal was present, together with diminished number of calls when the signal was not present.

Indications for the tracheoesophageal diversion procedure and the laryngotracheal separation procedure

Impaired protective function of the larynx can lead to intractable aspiration, a severe and potentially fatal disorder. If medical therapy fails to prevent intractable aspiration, surgical separation of the upper respiratory tract from the digestive tract is necessary to prevent recurrent contamination of the respiratory system in these patients. Two such surgical procedures are the tracheoesophageal diversion procedure and the laryngotracheal separation procedure. Our approach to patients with intractable aspiration and the indications for the use of these surgical procedures for the prevention of aspiration are discussed.

The tracheoesophageal diversion and laryngotracheal separation procedures for treatment of intractable aspiration

Intractable aspiration is a severe and often fatal complication in patients with impaired protective function of the larynx. This problem is usually a result of central nervous system disorders such as cerebrovascular accident, trauma, neoplasms, or degenerative disease. Surgical separation of the upper respiratory tract from the digestive tract can prevent recurrent contamination of the respiratory system in these patients. Two such procedures are the tracheoesophageal diversion procedure and a modification of this operation, the laryngotracheal separation procedure. The Virginia Mason Medical Center experience with these procedures, their indications, technique, and outcome are presented. In addition, cases of successful surgical reversal of the diversion procedures are discussed.

Cerebellar regulation of phonation in rhesus monkey (Macaca mulatta)

SummaryFive rhesus monkeys (Macaca mulatta) were trained to emit a “coo” vocalization with a duration of at least 500 msec. After stable performance was achieved cerebellar lesions were introduced, and various pre- and postlesion measures of phonation and of laryngeal EMG activity were compared to assess the effects of the lesions. The phonatory changes were interpreted with respect to possible laryngeal or respiratory modifications. The relation between fundamental frequency and intensity of phonation was changed in some animals, with no obvious alterations in either fundamental frequency or intensity considered separately. Intensity of phonation was decreased while duration was prolonged in two animals. Fundamental frequency of phonation was also affected in some animals. Reliable laryngeal EMG was obtained in two animals and was affected by cerebellar lesions. These results indicate that normal cerebellar function is involved in the control of fundamental frequency, intensity, duration, and the coordination of the laryngeal and respiratory systems for the control of phonation.

Surgical labyrinthectomy in the older patient

OBJECTIVE: Ablation of vestibular function is a highly efficacious option in the treatment of disabling vertigo arising from unilateral labyrinthine dysfunction. Regardless of the method used to ablate vestibular function, permanent posttreatment impairment of the balance function will develop in a number of treated patients. Many physicians who are involved in the care of the older patient with episodic vertigo are reluctant to recommend or perform a vestibular ablation procedure, because this treatment may result in permanent disequilibrium, which may be more detrimental to the older patient than the episodic vertigo. This study evaluates the outcome in older patients who underwent unilateral surgical labyrinthine ablation. METHODS: A retrospective analysis was done of the cases of 30 patients, all more than 60 years old, who underwent unilateral vestibular ablation because of disabling episodic vertigo by either transmastoid labyrinthectomy (n = 22) or transcanal labyrinthectomy (n = 8). RESULTS: Episodic vertigo was controlled in 95.5% of the patients in the transmastoid labyrinthectomy group and in 100% of those in the transcanal labyrinthectomy group. Postoperative imbalance was present in 22.7% of patients in the transmastoid labyrinthectomy group and in 62.5% of those in the transcanal labyrinthectomy group. CONCLUSIONS: Vestibular ablation is a viable option in the treatment of disabling vertigo in the older patient. A transmastoid labyrinthectomy may be preferable to a transcanal labyrinthectomy because the incidence of permanent posttreatment imbalance is less with a transmastoid labyrinthectomy. (Otolaryngol Head Neck Surg 1998;118:739-42.)

Discriminative phonation in macaques: effects of anterior mesial cortex damage

SummaryLesion damage of the anterior midline hemisphere in M. mulatta results in impaired discriminative vocal activity. Destruction of the supplementary motor area (SMA) or pre-SMA greatly increases vocal response latency without similar changes in a non-vocal response. Discrimination and efficiency in performing the vocal and non-vocal responses are unaffected by this damage. The behavioral deficit reflects a specific loss in initiating vocal signals.

Surgery for vertigo in the nonserviceable hearing ear: Transmastoid labyrinthectomy or translabyrinthine vestibular nerve section

Two of the surgical options that exist for the treatment of disabling vertigo arising from an ear with nonserviceable hearing are a transmastoid lab‐yrinthectomy (TL) and a translabyrinthine vestibular nerve section (TLVNS). The major difference between the two operations is a section of the vestibular nerves with the TLVNS which removes all preganglionic vestibular tissue from the diseased inner ear. It has been inferred that a TLVNS should be the procedure of choice if hearing is not to be spared, because a TL results in an incomplete removal of preganglionic vestibular tissue, and that this remaining tissue might have continued or recurrent physiologic function resulting in further vertigo. The clinical outcome of 58 patients who had either TL or TLVNS for disabling vertigo arising from a nonserviceable hearing ear was investigated with respect to the control of vertigo and the development of postoperative balance dysfunction. The control of vertigo in the TLVNS and TL groups was 100% and 95.3%, respectively. This difference was not statistically significant. There was a tendency for postoperative dys‐equilibrium to be more frequent in the TLVNS group, but this finding did not reach statistical significance. A TL appears to offer the same benefit as TLVNS in the control of intractable episodic vertigo without the additional risks of TLVNS.

Muscle spindles in nonhuman primate laryngeal muscles.

A total of 38 intrinsic laryngeal muscles from baboon (Papio papio), rhesus macaque (Macaca mulatto) and pigtail macaque (M. nemestrina) were examined for the presence of muscle spindles. A total of 20 spindles were found distributed within 10 thyroarytenoid, 8 cricothyroid, and 11 posterior cricoarytenoid muscles. Spindle density in these samples is similar to that reported for these muscles in humans. The morphological features of the spindles were found to be similar for human and nonhuman primates.