complex. We also wish to characterize the genetic basis for this condition in the family. Methods: A six generation Caucasian family originating from the center of Brazil was followed over ten years and data was collected from 146 members. Clinical data collected has included detailed case histories, otolaryngological and neurological examinations, audiometric evaluation, vestibular testing and imaging studies. Serial clinic and audiometric evaluations were done. We have also undertaken a genome wide linkage analysis in 64 family members and subsequent fine mapping using microsatellite markers. Results: Our study reveals an autosomal dominant pattern of transmission with incomplete penetrance of the gene and variable expression. Of the 146 members, 32 suffer from migraine with aura. Of these 32 individuals, 10 also suffer from episodic vertigo, tinnitus and/or aural fullness. Audiometric evaluation did not show classic low tone fluctuating sensorineural hearing loss (SNHL). Imaging studies were normal. In this family, migraine preceded the neuro-otological symptoms by 15-20 years on average. Overall, migraine symptoms decreased with time, while the vertigo symptoms had a tendency to get worse. Ge- netic analysis revealed an area with high lod scores in chromosome 5. Therefore, the genetic locus for this symptom complex in this family appears to be on chromosome 5. Studies are ongoing to investigate candidate genes in this locus.
A clinical study of the efferent auditory system in patients with normal hearing who have acute tinnitus. Otol Neurotol. 2007 Feb;28(2):185-190. Riga M, Papadas T, Werner JA, Dalchow CV, Department of Otorhinolaryngology, Head and Neck Surgery, University of Patras, Greece.
Objective: Etiological diagnosis and treatment of tinnitus still remain challenging in clinical practice. The aim of this study was to determine the potential contribution of a defective cochlear efferent innervation to the onset of tinnitus in patients with normal hearing. Study design: Prospective randomized controlled study. Setting: Otorhinolaryngology department of a general hospital. Patients: The patient group consisted of 18 normal-hearing adults (7 men, 11 women) with acute tinnitus (bilateral in 3 patients). Interventions: Tympanogram, stapedial muscle reflex, pure tone audiometry, tinnitus pitch matching, spontaneous otoacoustic emissions, and distortion product otoacoustic emissions (DPOAEs) in the ab- sence and presence of contralateral suppression by white noise. Main outcome messure: DPOAEs suppression amplitudes recorded from tinnitus and nontinnitus ears of the patients‘ group were compared with each other and with a control group. RESULTS: The contra- lateral application of white noise induced the enhancement of DPOAE amplitudes in some patients. The suppression of DPOAE amplitudes by contralateral white noise did not reach statistically significant le- vels in either ear (with or without tinnitus). On the contrary, under the same conditions, our control group demonstrated statistically significant reduction of DPOAE amplitudes at all frequencies. Conclusion: Patients with normal hearing acuity who have acute tinnitus seem to have a less effective functioning of the cochlear efferent system because the application of contralateral noise enhanced the DPOAEs or suppressed them less intensely than it did in a control group. Further studies may establish the clinical applications for the diagnosis of changes in efferent function, in the subjective evaluation, patient etiological grouping, treatment, or prognosis of tinnitus.
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