1/58. Central auditory dysfunction.The numerous tests applicable to the assessment of central deafness are briefly reviewed. It is likely that the more specific verbal and non-verbal tests, which assess more complex auditory function, will prove to be most useful in the assessment of these problems. We believe that the concept of a spectrum of clinical-anatomical types of central deafness is useful, namely, cortical, brainstem and more peripheral forms; a detailed study of an example of a predominantly brainstem type of central deafness is presented. An interdisciplinary approach which applies the methods of the audiologist, otolaryngologist, and neurologist to these patients is required to localize the site of the lesion, to detect and describe the deafness and to establish its etiology.- - - - - - - - - - ranking = 1keywords = brain (Clic here for more details about this article) |
2/58. Clinical findings for a group of infants and young children with auditory neuropathy.OBJECTIVE: To examine the prevalence of auditory neuropathy in a group of infants at risk for hearing impairment and to present an overview of the clinical findings for affected children. DESIGN: Results for 20 subjects who showed repeatable cochlear microphonic potentials in the absence of click-evoked auditory brain stem responses are included in this study. Behavioral and steady state evoked potential thresholds were established in each case. Where possible, otoacoustic emission and speech perception results (unaided and aided) also were obtained. RESULTS: One in 433 (0.23%) of the children in our series had evidence of auditory neuropathy. The audiometric findings for these subjects varied significantly, with behavioral thresholds ranging from normal to profound levels. Discrimination skills were also variable. Approximately half of the subjects showed little understanding, or even awareness, of speech inputs in both the unaided and aided conditions. There were, however, a number of children who could score at significant levels on speech discrimination tasks and who benefited from the provision of amplification. CONCLUSION: The results suggest that auditory neuropathy is more common in the infant population than previously suspected. The effects of neuropathy on auditory function appear to be idiosyncratic, producing significant variations in both the detection and discrimination of auditory signals. As such, the management of children with this disorder must allow for individual differences.- - - - - - - - - - ranking = 0.5keywords = brain (Clic here for more details about this article) |
3/58. Outcome of a baby born from a mother with acquired juvenile hypothyroidism having undetectable thyroid hormone concentrations.We report a baby born from a mother with strongly positive thyroid stimulation blocking antibody (TSBAB) and nearly undetectable T4 level. This case is a unique model of nearly complete absence of thyroid hormones during fetal and early neonatal life in humans. The infant girl was born by cesarean section, because of fetal bradycardia, after 41 weeks gestation and received mechanical ventilation for 3 days. The TSH level was more than 120 microU/mL in the neonatal thyroid screening. At age 17 days, the results of a thyroid function study showed undetectable free T3 and free T4 concentrations, TSH 550 microU/mL, and TSH receptor antibody (TRAB) 87%. thyroxine at a dose of 30 microg/day was started at age 17 days. The patient required thyroxine treatment until age 8 months. The brain magnetic resonance image at age 2 months revealed reduced brain size. Her auditory brain stem response was absent at age 2 months. The audiogram at age 4 yr revealed sensorineural deafness of 70 dB. When she was 6 yr of age, motor development remained the same as that at age 4 months. Her height was 106 cm (- 1.5 SD). The results of thyroid function study of the mother 23 days after delivery showed undetectable free T3 and free T4, TRAB 84%, and TSBAB 83%. In conclusion, the outcome of severe thyroid hormone deficiency in utero and early in human neonatal life was normal physical growth, fetal distress resulting in cesarean section, difficulty in the onset of breathing, permanent deficit in auditory function, brain atrophy, and severely impaired neuromotor development despite the start of an adequate dose of thyroxine replacement during the neonatal period.- - - - - - - - - - ranking = 2keywords = brain (Clic here for more details about this article) |
4/58. Otoacoustic emissions and auditory brainstem responses after neonatal hyperbilirubinemia.Severe hyperbilirubinemia often results in hearing loss. Behavioral audiometry, auditory-evoked brainstem responses (ABRs) and otoacoustic emissions (OAEs) were performed in three such patients in an attempt to localize the pathophysiology of this hearing loss. Behavioral audiometric findings in these patients (all male, 4, 15 and 25 years old) ranged from severe in the 4-year-old, moderate in the 15-year-old and slight in the 25-year-old. Where obtained, ABR wave V thresholds were elevated or ABR were absent. However, absolute and inter-wave latency measurements were not indicative of brainstem pathology. OAEs (transient and distortion product) could only be obtained in the high- or low-frequency ranges in these patients. Our findings suggest that at least some lesions producing hearing loss in severe hyperbilirubinemia are in the cochlea, especially at the outer hair cells. Finally, we found that only moderately elevated serum bilirubin levels (<20 mg/dl) may contribute to the development of sensorineural hearing loss.- - - - - - - - - - ranking = 3keywords = brain (Clic here for more details about this article) |
5/58. Lesions of the internal auditory canal and cerebellopontine angle in an only hearing ear: is surgery ever advisable?OBJECTIVE: To define the indications for surgery in lesions of the internal auditory canal (IAC) and cerebellopontine angle (CPA) in an only hearing ear. STUDY DESIGN: Retrospective case series. SETTING: Tertiary referral center. patients: Seven patients with lesions of the IAC and CPA who were deaf on the side opposite the lesion. Five patients had vestibular schwannoma (VS), and one each had meningioma and progressive osseous stenosis of the IAC, respectively. The opposite ear was deaf from three different causes: VS (neurofibromatosis type 2 [NF2]), sudden sensorineural hearing loss, idiopathic IAC stenosis. INTERVENTION(S): Middle fossa removal of VS in five, retrosigmoid resection of meningioma in one, and middle fossa IAC osseous decompression in one. MAIN OUTCOME MEASURE: Hearing as measured on pure-tone and speech audiometry. RESULTS: Preoperative hearing was class A in four patients, class B in two, and class C in one. Postoperative hearing was class A in three patients, class B in one, class C in two, and class D in one. CONCLUSIONS: Although the vast majority of neurotologic lesions in an only hearing ear are best managed nonoperatively, in highly selected cases surgical intervention is warranted. Surgical intervention should be considered when one or more of the following circumstances is present: (1) predicted natural history of the disease is relatively rapid loss of the remaining hearing, (2) substantial brainstem compression has evolved (e.g., large acoustic neuroma), and/or (3) operative intervention may result in improvement of hearing or carries relatively low risk of hearing loss (e.g., CPA meningioma).- - - - - - - - - - ranking = 0.5keywords = brain (Clic here for more details about this article) |
6/58. The effect of midline petrous apex lesions on tests of afferent and efferent auditory function.OBJECTIVES: Historically, audiological procedures have focused on the assessment of the afferent (ascending) cochlear-VIIIth nerve system and have, for the most part, ignored the efferent (descending) auditory system. We report afferent and efferent auditory test results for two cases with a cholesterol cyst of the right petrous apex; one lesion involves the afferent segment of the auditory system, and the second lesion involves both the afferent and efferent segments of the auditory system. These "natural experiments" provide a unique opportunity to study the effect of a space-occupying lesion of the petrous apex on afferent and efferent function of the auditory system. DESIGN: Transient evoked otoacoustic emission (TEOAE) suppression studies were performed to assess the effect of the cholesterol cyst on the efferent system of the two cases. In addition, three complementary afferent tests of brain stem auditory function were administered: 1) acoustic reflex thresholds (ARTs); 2) masking level difference (MLD); and 3) auditory brain stem response (ABR). These tests are complementary because the superior olivary complex (SOC) is involved not only in the mediation of the sound evoked efferent reflex assessed in TEOAE suppression, but in the mediation of the ARTs, the MLD, and the ABR. RESULTS: The two cases with midline petrous apex lesions, one not involving the VIII-cochlear efferent auditory system, differed from each other with regards to TEOAEs suppression, and ARTs. Specifically, the case with only afferent involvement produced normal TEOAE suppression, a normal MLD, normal ARTs, and abnormal waves III and V of the ABR, whereas the case with both afferent and efferent involvement produced abnormal TEOAE suppression, a normal MLD, abnormal ARTs, and abnormal waves III and V of the ABR. CONCLUSIONS: These cases illustrate that although several auditory tests can be mediated within the same or adjacent anatomical structures, i.e., the SOC, they may not be equally affected by the same lesion due to different physiology. Further, the TEOAE suppression paradigm is a clinically relevant test to assay the sound evoked efferent reflex that is mediated by the medial olivocochlear system of the SOC.- - - - - - - - - - ranking = 1keywords = brain (Clic here for more details about this article) |
7/58. Pineal region tumor manifesting initially as hearing impairment.An 18-year-old male presented with a pineal region germinoma with hearing impairment as the chief complaint. Magnetic resonance image demonstrated a well-enhanced multi-cystic tumor extending into the upper fourth ventricle and wall of the bilateral lateral ventricles. audiometry revealed bilateral mild hearing impairment in the low frequencies. Auditory brainstem response recording showed low amplitudes in all waves (IV-V/I ratio < 1) with prolong latencies (I-V and III-V) on the right but no discernable wave at 60 dB clicks on left. Hearing impairment and audiometric findings were improved after ventriculoperitoneal shunt operation. The hearing impairment appeared to be a mixed (conductive and sensorineural) type. The tumor was responsible for the sensorineural deafness because of invasion and compression of the central auditory structures. The inferior brachium was maximally compressed anterolaterally by the dilated bilateral lateral ventricles and posteromedially by the tumor. hydrocephalus caused conductive deafness by halting or arresting the footplate of stapes movement, as a consequence of high-pressure transmission through the cochlear aqueduct.- - - - - - - - - - ranking = 0.5keywords = brain (Clic here for more details about this article) |
8/58. Delayed visual maturation associated with auditory neuropathy/dyssynchrony.Delayed visual maturation is a term used to describe infants who initially seem blind but subsequently have a marked improvement. The mechanism of visual loss and the subsequent improvement remains unknown. Auditory neuropathy/dyssynchrony is a condition of hearing impairment associated with absent or severely abnormal brainstem auditory evoked potentials but normal cochlear functions as measured by otoacoustic emissions. In this report, a 9-month-old infant who had no visual fixation for the first 3 months of life and congenital hearing impairment is described. Her brainstem auditory evoked potential study at 2.5 months of age showed no response to click stimuli presented at 90 dB nHL, whereas her otoacoustic emissions were normal. Subsequently, her vision and hearing improved. A brainstem auditory evoked potential study at 9 months of age showed reproducible waveforms. This case suggests the need for a detailed hearing evaluation of children with delayed visual maturation. Furthermore, this case highlights the need for follow-up brainstem auditory evoked potential testing prior to pursuing any audiologic intervention.- - - - - - - - - - ranking = 2keywords = brain (Clic here for more details about this article) |
9/58. Molecular genetic delineation of a deletion of chromosome 13q12-->q13 in a patient with autism and auditory processing deficits.In a sporadic case of autism and language deficit due to auditory processing defects, molecular genetic studies revealed that a chromosomal deletion occurred in the 13q12-->q13 region. No chromosome abnormalities were detected in the parents. We determined that the deletion occurred on the paternally derived chromosome 13. There are two previous reports of chromosome 13 abnormalities in patients with autism. The deletion in the subject described in this paper maps between the two chromosome 13 linkage peaks described by Bradford et al. (2001) in studies of subjects with autism and language deficits. The 9-Mb region deleted in the patient described here contains at least four genes that are expressed in brain and that play a role in brain development. They are NBEA, MAB21L1, DCAMKL1 and MADH9. These genes therefore represent candidate genes for autism and specific language deficits.- - - - - - - - - - ranking = 1keywords = brain (Clic here for more details about this article) |
10/58. Wegener's granulomatosis presenting with otologic and neurologic symptoms: clinical and pathological correlations.A case of Wegener's granulomatosis in a 59-year-old woman is reported. The disease first involved the parotid gland, the brain stem and the spinal cord, then running a rapidly progressive course as systemic pathology. Anti-neutrophil cytoplasmic antibody (cANCA) levels raised as renal failure set in. Renal biopsy confirmed the diagnosis of Wegener's granulomatosis and an appropriate therapy was adopted.- - - - - - - - - - ranking = 0.5keywords = brain (Clic here for more details about this article) |
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