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Brainstem Auditory Evoked Responses (brainstem + auditory_evoked_response)
Selected AbstractsMOSHER AWARD HONORABLE MENTION,THE LARYNGOSCOPE, Issue 4 2000Natural History of Acoustic Neuromas Abstract Objectives/Hypothesis 1) Develop a computerized technique to accurately compare acoustic neuroma size on routine computed tomography and magnetic resonance imaging (MRI) scans; 2) use this technique to determine the growth pattern in a large series of patients with acoustic neuroma who were conservatively managed; 3) describe the natural history of patients with acoustic neuromas who did not receive surgical intervention and those who underwent subtotal resection; 4) correlate the size and growth rate of acoustic neuromas to clinical presentation and auditory and vestibular testing; and 5) recommend guidelines for the management of patients with acoustic neuromas. Study Design A retrospective study from 1974 to 1999 of patients with unilateral acoustic neuromas who had conservative treatment by serial imaging studies (80 patients) or subtotal resection (49 patients). Methods All patient charts were evaluated for presenting symptoms, reasons for the type of management given, and clinical outcome. Charts were also reviewed with respect to serial audiological assessment, electronystagmography, and brainstem auditory evoked response. Imaging studies were analyzed using a computer technique so that serial studies could be compared to determine growth rates. Results Rigorous computer analysis of tumor size and growth rate was statistically the same as the radiologist's description of the tumor size and growth rate. Of 70 patients who were older than 65 years of age old at the time their tumor was discovered, 4 (5.7%) required intervention and 18 (26%) were dead of unrelated causes. These patients had a mean follow-up of 4.8 years (range, 0.01,17.2 y). Overall, growth rate for nonsurgical patients was 0.91 mm per year. Nonsurgical tumors did not grow or regressed in 42.3%. Overall postoperative growth rate for surgical subtotal resection patients was 0.35 mm per year. Surgical tumors did not grow or regressed after subtotal resection of acoustic neuroma in 68.5% of patients. Three patients (6.1%) required revision surgery because of tumor growth or the development of symptoms. Neither auditory nor vestibular testing was a reliable measure for determining tumor growth. Conclusion Measurement of the maximal tumor diameter on MRI scans is a reliable method for following acoustic neuroma growth. There is no need to perform a rigorous analysis of tumor size to determine whether the tumor is growing significantly. The vast majority of patients older than 65 years with acoustic neuromas do not require intervention. The indications for intervention should be based on a combination of rapid tumor growth with the development of symptoms. [source] Age-related changes in BAER at different click rates from neonates to adultsACTA PAEDIATRICA, Issue 8 2009Ze Dong Jiang Abstract Aim:, To characterize age-related changes in brainstem auditory evoked response (BAER) at different click rates from neonates to adults. Methods:, BAER was studied at repetition rates 11,91/sec of clicks in 165 normal neonates and children of various ages and 29 young adults. Results:, BAER wave latencies and inter-peak intervals increased linearly with increasing click rate at all ages. The younger was the age, the greater were BAER click rate-dependent changes. At 9 months and younger, the slopes of latency- and interval-rate functions were all significantly greater than in the adults (all p < 0.01). The slopes of wave I latency- and I,III interval-rate functions at 1,2 years and older were similar to those in adults. The slopes of wave III and V latency-rate functions and I,V and III,V interval-rate function at 3,4 years and older did not differ significantly from those in adults. Conclusion:, BAER is affected by stimulus rate more in younger children than in the older. Adult-like rate-dependent changes are reached at 1,2 years for wave I latency and I,III interval, and 3,4 years for wave III and V latencies and I,V and III,V intervals. Our BAER data at different click rates provide normal references for subjects of various ages. [source] Prevalence of Unilateral and Bilateral Deafness in Border Collies and Association with PhenotypeJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 6 2006Simon Platt Background:Congenital sensorineural deafness (CSD) occurs in Border Collies, but its prevalence and inheritance are unknown. This study estimated the prevalence of CSD in Border Collies and investigated its association with phenotypic attributes linked to the merle gene, including coat pigmentation and iris color. Hypothesis:Deafness in Border Collies is associated with pigmentation patterns linked to the merle gene. Animals:A total of 2597 Border Collies from the United Kingdom. Methods:A retrospective study of Border Collies tested, during 1994,2002, by using brainstem auditory evoked responses. Associations between deafness and phenotypic attributes were assessed by using generalized logistic regression. Results:The prevalence of CSD in puppies was estimated as 2.8%. The corresponding rates of unilateral and bilateral CSD were 2.3 and 0.5%, respectively. Adjustment for clustering of hearing status by litter reduced the overall prevalence estimate to 1.6%. There was no association between CSD and sex (P= .2). Deaf Border Collies had higher rates of merle coat pigmentation, blue iris pigment, and excess white on the head than normal hearing Border Collies (all P < .001). The odds of deafness were increased by a factor of 14 for Border Collies with deaf dams, relative to the odds for dogs with normal dams (P= .007), after adjustment for phenotypic attributes. Conclusions and Clinical Importance: Associations between CSD and pigmentation patterns linked to the merle gene were demonstrated for Border Collies. Evidence for an inherited component to CSD in Border Collies supports selective breeding from only tested and normal parents to reduce the prevalence of this disease. [source] Objective assessment of neurotoxicity while shifting from carbamazepine to oxcarbazepineACTA NEUROLOGICA SCANDINAVICA, Issue 5 2004B. Clemens Objectives , Objective assessment of non-overt neurotoxicity of carbamazepine (CBZ) vs oxcarbazepine (OXC) in patients with difficult-to-treat partial epilepsy, who were resistant to CBZ treatment and were converted from CBZ monotherapy to OXC monotherapy. Material and methods , Therapeutically equivalent doses (150 mg OXC for every 100 mg CBZ) were compared in 20 adult patients. Neurological investigation, conventional and spectral EEG analysis, brainstem auditory evoked responses (BAER) were carried out in both treatment conditions. EEG and BAER data of 20 age-matched healthy controls helped interpretation. Primary target variables (electrophysiological parameters) were evaluated blindly. Results , There were no significant differences between treatment conditions concerning the neurological condition, lack of clinically evident neurotoxicity, seizure frequency and EEG spike frequency. OXC treatment was characterized by less delta, theta, and alpha power, more beta power, and significantly greater mean alpha frequency (P = 0.03 and 0.05 for the left and right occipital leads, respectively), than CBZ treatment. Interpeak latencies were prolonged in the CBZ condition as compared with normals (P = 0.01) and OXC (P = 0.02). Conclusion , In this cohort of patients substitution of OXC for CBZ was associated with significant normalization of electrophysiological parameters, indicating decreasing neurotoxicity while shifting from CBZ to OXC monotherapy. [source] Comparison of brainstem auditory evoked responses recorded at different presentation rates of clicks in term neonates after asphyxiaACTA PAEDIATRICA, Issue 12 2001ZD Jiang This study examined whether high presentation rates of clicks while recording brainstem auditory evoked responses (BAER) can improve the detection of central auditory impairment in asphyxiated neonates using the BAER. The BAER was analysed at different presentation rates of clicks within the first week after birth in 38 term neonates who suffered perinatal asphyxia. At the routinely used 21 s,1 clicks all BAER wave latencies increased significantly (ANOVA, p < 0.05-0.01). After excluding five neonates who had a significantly elevated BAER threshold, only wave V latency increased slightly (p < 0.05). The interpeak intervals of I,V and III,V also increased slightly (both p < 0.05). Similar results were found at 51 s,1 clicks. As the clicks were increased to 91 s,1, the III,V interval increased more significantly (p < 0.01) and the III,V/I,III interval ratio also increased significantly (p < 0.01). In particular, wave V amplitude reduced more significantly than that in normal term controls (p < 0.01). Compared with values in the controls, wave V amplitude reduced by 4.5%, 12.2% and 24.7% at 21, 51 and 91 s,1 clicks, respectively. Conclusion: Although a moderate increase in the rate (e.g. 51 s,1) while recording the BAER did not improve the detection of hypoxic-ischaemic auditory impairment, a significant increase (e.g. 91 s,1) did, which mainly indicates an abnormal reduction in wave V amplitude. [source] | ||||||||||