[An unusual localization of thryoglossal duct cyst]. / Localizzazione inusuale di cisti del dotto tireoglosso.

Thyroglossal duct cysts are most common neck masses after benign lymphonodes. They originate from primitive thiroglossal duct, so they could be locate along its course. Every mass in the middle line of the neck can be considered as a thyroglossal cyst. Best treatment is surgery (Sistrunk procedure). We present a case of unusual localization at floor of the mouth of thyroglossal in a 34 years old woman. To our knowledge in literature, only two cases, have been reported both.

Video-based system for intraoperative facial nerve monitoring: comparison with electromyography.

OBJECTIVE: To validate a recently developed intraoperative facial nerve monitoring system that is based on video control of facial movements. STUDY DESIGN: In a single-subject design study, involving 15 otoneurosurgical patients, the relationship between intensity of neural stimulation, facial movements, and electrophysiologic voltage were measured. The analysis was performed by measuring the ipsilateral oral commissure displacement in relation to different levels of current administered to the nerve during surgical procedures. SETTING: Electromyography and video system intraoperative facial nerve monitoring. PATIENTS: 15 patients (9 men, 6 women; mean age, 61 yr) undergoing a translabyrinthine approach for removal of acoustic neuroma. RESULTS: Electromyography showed slightly greater sensitivity. With regard to the stimulation-response ratio, facial movement and electromyographic amplitude showed very similar responses. CONCLUSIONS: The video system was considered useful in terms of validity and reliability. Furthermore, the authors' surgical experience showed some limitations of electromyography, especially in terms of electrical artifact during cauterization, totally masking the electrophysiologic monitoring.

Initial experience of peroperative electrocochleography monitoring in stapedectomy.

Clinical experience of intraoperative ECochG monitoring during stapes surgery is reported. Selected surgical phases have been taken into consideration, laying particular stress on the phase corresponding to the opening of the labyrinthine spaces. Compound action potential (CAP) amplitude and latency showed, a supposed, an inversely proportional relationship in most of the cases. Abnormal findings were also recorded in some patients, thus giving rise to different electrophysiological hypotheses. A proposal for an "in vivo" model for the study of the electrophysiological changes due to the opening of labyrinthine spaces is made.

High-frequency audiometry in children.

On the grounds of recent literature and of their own previous studies, the authors have examined a group of 25 normal-hearing children, ranging from 7 to 10 years of age, with high-frequency audiometry. The results were compared with those obtained in a group of young adults. On the basis of these findings, average threshold values were derived for this age group; such data have not yet been published for this simple headset technique. Furthermore, the comparison between the two age groups enabled the authors to determine a deterioration of the high-frequency hearing threshold which takes place at a fairly early age. Reliability of the equipment, in which headphones were used as transducers, was checked and the reproducibility for this test was shown to be adequate, as seen from the low test-retest variability.

High-frequency audiometry above 8 kHz. Comparative results of normative thresholds obtained with a headphone system and a quasi-free-field system.

Since a standard method for high-frequency audiometry does not yet exist, the authors, using 20 young subjects, compare the results obtained with a quasi-free-field system devised by Osterhammel et al. [Scand. Audiol. 6:91-95, 1977] and those obtained by a headphone system. The headphone system is considered to be better, because it offers many practical advantages.

Electrocochleographic findings: Menière's disease versus sudden sensorineural hearing loss.

Electrocochleography was conducted in 185 patients with Menière's disease and 117 with sudden deafness. Electrophysiological findings from the two groups were compared in order to identify pathogenic similarities between the two conditions. Parameters investigated were the summating potential (SP)/action potential (AP) ratio, audiometric profiles and audiometric changes after medical therapy. A high SP/AP ratio was found in the patients with sudden deafness, thus supporting a possible hydropic aetiology in this group. In conclusion, electrocochleography can be considered a useful technique as it permits identification of an hydropic condition in certain cases of sudden deafness.

Intraoperative videomonitoring of the facial nerve.

OBJECTIVE: To propose the application of an intraoperative videomonitoring system in otologic and otoneurologic surgery. The authors also compare results obtained by using this system with findings deriving from electromyography and pneumosensorial monitoring methods. STUDY DESIGN: The single-subject design study, involving six patients with middle ear or otoneurosurgery, compares reliability of different monitoring procedures, especially in terms of advantages and drawbacks. SETTING: Video system versus electrophysiologic and pneumosensorial systems. PATIENTS: Two patients affected with chronic otitis media, two from Meniere's disease, and two from Acoustic Neuroma. INTERVENTIONS: Intraoperative diagnostic and prognostic. RESULTS: Electrophysiologic method shows more sensibility, but is affected by a moderate grade of false positive because of electric artifacts; videomonitoring system showed less sensibility, but appears reliable; pneumosensorial system gives in-between results. CONCLUSIONS: In intraoperative monitoring techniques, reliability and feasibility are the most important factors and are achieved, in this study, by the videomonitorig system. Video recording of images have permitted further off-line analysis.

'Quasi free-field' audiometry: proposal for a modified transducer system.

The authors studied a group of 13 young adults by using high-frequency techniques in 'quasi free-field' conditions, as suggested by Osterhammel, and comparing the results with those obtained by means of an original method suggested by the present study group. The data relative to this last-mentioned technique confirmed it as being valid on the grounds of test-retest findings and standard deviation. It is concluded that both methods are equally effective for the study of the physiology of the ear, but that the present method is less practical from the clinical point of view.