Cervical necrotizing fasciitis of odontogenic origin.

Necrotizing fasciitis is a severe soft tissue infection caused by both aerobic and anaerobic bacteria and is characterized by a rapid extension along fascial planes and by necrosis of soft tissues. The disease rarely occurs in the head and neck. Three cases of necrotizing fasciitis of the neck after a dental infection are presented. The difficulty in diagnosing the early stage of this condition in relation to other soft tissue infections of odontogenic origin in the neck is discussed. The importance of an early diagnosis followed by an appropriate combination of medical, surgical, and dental treatment is emphasized.

Changes in auditory function associated with 2-cyano-butyl-acrylate adhesive implanted in the middle ear of experimental animals.

The effects on auditory function caused by the implantation of 2-cyano-butyl-acrylate adhesive in the middle ear was investigated in experimental animals. Auditory brainstem responses to click stimuli were used to measure hearing thresholds prior to and following implantation of 2-cyano-butyl-acrylate adhesive in the middle ear of guinea pigs. A permanent and deep threshold shift observed at 2 months in 62% of the examined animals, suggested that this tissue adhesive is an ototoxic middle ear implant material and should not be considered in reconstructive middle ear surgery. The functional data correlate well with some of the previous morphological observations.

Auditory brain-stem responses in guinea pigs following middle ear implantation of Ceravital.

The effects on auditory function caused by implantation of the bioactive glass ceramic Ceravital in the middle ear of guinea pigs was investigated. Auditory brain-stem responses (ABR) were used to measure hearing function. A threshold shift due to a conductive hearing loss was observed immediately post-operatively. This threshold shift increased towards the 20th post-operative day and improved thereafter. Surgical manipulation of the middle ear and biochemical reactions between the Ceravital granules and the middle ear wall may have contributed respectively to the immediate and late temporary ABR threshold shift recorded. However, cochlear function was not affected by middle ear implantation of Ceravital. These results correlate well with morphological studies of Ceravital implanted in the middle ear and give further support to the safe use of Ceravital as an implantation material in middle ear reconstructive surgery.

Acute airway obstruction and achalasia of the esophagus.

Patients with achalasia tolerate considerable distension of the esophagus. Respiratory symptoms usually are due to regurgitation and pulmonary aspiration of retained food rather than to a space-occupying mechanism. We describe a case of previously undiagnosed achalasia presenting in an elderly woman with symptoms consistent with tracheal obstruction of acute onset.

Sudden hearing loss in the elderly.

In elderly subjects suffering from presbycusis a clinical picture of sudden hearing loss, tinnitus and vertigo may be precipitated by a superimposed serous otitis media. Such an abrupt and dramatic sensory deficiency may be erroneously ascribed to an acute cochlear lesion and given grave prognostication. This situation was observed in 12 patients during a period of 2 years. Appropriate diagnostic evaluation revealed the true nature of the disease and simple therapeutic measures promptly restored the auditory function to its previous level.

Maturation of auditory brainstem potentials in neonates and infants.

Auditory brainstem evoked potentials (ABP) were recorded in 59 healthy neonates and infants whose age ranged from 3 days to 18 months (6 age groups). Latencies of individual waves and the interpeak latencies (IPL) of I-III, III-V and I-V were analysed. A different maturational pattern was observed in the pontomedullary and the pontomesencephalic segments of the brainstem. Latencies of all waves except wave I were longer in male than in female babies. Establishment of normative data related to the technical variables employed by the individual team is a sine qua non prerequisite for adequate neurological evaluation of ABP.

Measurement of auditory brain stem potentials in Bell's palsy.

Auditory brain stem potentials (ABP) were recorded in 27 patients with Bell's palsy during the early phase of the disease and 1-3 months later. Pathological findings were observed in 6 patients, the dominant features being prolonged brain stem transmission time and diminished amplitude of the second wave. The extension of the pathological process in the so called idiopathic peripheral facial paralysis appears to vary. The observation of brain stem involvement in some patients with Bell's palsy may have important clinical implications.

Parotid gland hemorrhage as a complication of coumarin compound ingestion.

Bleeding in the salivary glands represents a very rare complication of oral anticoagulant therapy. Only one such case has been previously described in the submandibular glands. To the best of our knowledge, we document the first case of hemorrhage in the parotid gland following the ingestion of coumarin compounds.

CT pneumomeatography in the diagnosis of small acoustic neuromas.

The introduction of a small quantity of air by lumbar puncture in the lateral decubitus position followed by high-resolution computerized tomography (CT) scanning is a simple method allowing optimal visualization of the cerebellopontine angle cistern and the internal auditory meatus. Our experience with 37 CT pneumomeatographies in 22 patients who had clinical and audiometric findings suggestive of retrocochlear lesions is presented. Thirty-two examinations were normal, and 5 revealed small acoustic neuromas. In all cases, conventional X-rays, multidirectional tomography and contrast CT were nonconclusive. We advocate that CT pneumomeatography be the procedure of choice in the diagnosis of purely intracanalicular or very small extracanalicular acoustic neuromas.

Pontomedullary vs pontomesencephalic transmission time. A diagnostic aid in multiple sclerosis.

Caudal vs rostral transmission time has been studied in patients with multiple sclerosis (MS). In the majority of the cases, prolongation in latency was more severe in the caudal segment, which suggests that this part of the brainstem is more commonly affected in MS. The difference between pontomedullary and pontomesencephalic transmission time yields a variable that may prove a valuable adjunct in the electrodiagnosis of MS.

Auditory brain stem responses in thyroid dysfunction.

A characteristic pattern of ABR was observed in hyper-and hypofunction of the thyroid gland. The most conspicuous change took place in the BSCT. Its value correlated well with the level of serum T4. Dynamic changes of ABR pattern were recorded during the development of myxedema and on return to an euthyroid state. This preliminary study suggests that examinations of ABR may serve as a tool in the overall assessment of thyroid status.

Auditory function of Friedreich's ataxia. Electrophysiologic study of a family.

Hearing function and auditory brainstem potentials were evaluated in nine members of three generations of a family affected with Friedreich's ataxia. The characteristic findings were high-frequency sensorineural hearing impairment of varying severity and diminished or absent N1, N2, and N3 responses. These electrophysiologic aberrations correlate topographically with previously reported pathological observations.

The significance of acoustic admittance procedures in the audiologic evaluation of multiply-handicapped children.

The specific contribution of admittance procedures in the diagnosis of hearing impairment was studied in a group of 53 handicapped children. The value of admittance procedures was assessed in relation to that of otoscopy and pure tone audiometry. Admittance procedures and otoscopy were successfully performed in all but one of the children and indicated conductive pathology in about 40% of the subjects, whereas pure tone audiometry was not feasible or inconclusive in 30.2% of the subjects. In 5.7% of the subjects admittance procedures proved the only diagnostic tool.

Auditory brain stem responses in cerebellopontine angle tumors.

The characteristic features of auditory brain stem responses (ABSR) are described in seven cases of cerebellopontine angle tumors: five acoustic neuromas, one congenital cholesteatoma, and one meningioma. An attempt is made to correlate the N1 response with the degree of auditory nerve involvement, to gain information about the presence of brain stem displacement, and to evaluate the cranial extension of the lesion by recording responses to contralateral stimuli. The empirical nature of deductions based on crossed stimulation is emphasized. In tumors originating from the VIIIth nerve, the ABSR pattern is characterized by a well-defined N1 complex, indistinct or absent additional responses, and prolonged brain stem conduction time (BSCT) on the affected side whenever its assessment is feasible. Recording from the affected side on stimulation of the contralateral side may show normal responses from stations central to the auditory nerve in cases of small-sized tumors. Medium or large tumors may be accompanied by abnormal N2 and/or N3 responses suggesting involvement of these stations.

Assessment of functional integrity of brain stem auditory pathways by stimulus stress.

The effect of increasing the repetition rate of click stimuli on auditory brain stem responses has been studied in young subjects with normal hearing, in old people and in patients with multiple sclerosis. The most conspicuous effects have been observed in the amplitude of the responses, especially waves II and V, and in the value of the brain stem conduction time. Increased stimulation rates may serve as a method for the assessment of the functional status of the lower auditory pathways in diverse pathological conditions.

Tympanometry in normal neonates.

Acoustic conductance and susceptance tympanograms were obtained at 220 and 660 Hz in 34 neonates. The neonates were categorized into three age groups (8-24 hours, 24-60 hours, and 60-96 hours). Single-peaked, double-peaked, and monotonically increasing tympanograms were found. Static values for conductance, susceptance, admittance, resistance, reactance and impedance at the lateral surface of the tympanic membrane were computed from the tympanograms. There were no significant differences in mean static values among the three groups. At 220 Hz, the individual static reactance values were usually smaller than the static resistance values and often assumed a positive sign. At 660 Hz, the individual static reactance values always assumed a negative sign and were approximately equal to the static resistance values. The single- and double-peaked tympanograms apparently were the result of previously identified interactions between static resistance and reactance values. The data were compared to those of infants and adults. Tympanograms at 220 Hz were obtained for 13 of the original subjects at the age of three to four months. The data collected in this group were consistent with those reported in the literature for the same age group.

Variations in acoustic admittance related to type of ear tip. A plea for a standardized method.

In order to assess the validity of using various ear tips, tympanometry and acoustic admittance were studied in 20 young healthy subjects, and three different types of ear tip used to seal the external auditory canal. Significant variations in the admittance components and tympanometry curves were observed, resulting most probably from changes in the canal volume and the physical nature of the tipe. It appears advisable to develop and adopt an appropriate, standard ear tip for studies of admittance audiometry.