1/72. Successful cochlear implantation in a patient with melas syndrome.OBJECTIVE: To describe methods of assessing cochlear implant candidacy in patients with potentially significant peripheral and central nervous system (CNS) degeneration. STUDY DESIGN: A patient with a degenerative CNS disease (melas syndrome) undergoing evaluation for cochlear implantation is described. SETTING: This study took place at a tertiary care center. PATIENT: A patient with mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) who had cortical blindness and profound sensorineural hearing loss was evaluated and rehabilitated with cochlear implantation. INTERVENTIONS: Pure-tone audiogram, behavioral responses to promontory stimulation electrical auditory brainstem response, and electrically evoked middle-latency responses (MLRs) were used to assess eighth nerve, auditory brainstem, and cortical auditory pathways. cochlear implantation with Cochlear Corporation mini 22 implant was performed. RESULTS: Repeatable electrically evoked MLRs and behavioral responses to promontory stimulation documented the presence of auditory cortical responses. Successful implantation resulted in open set speech recognition and communication using the auditory/oral mode. CONCLUSION: This report describes successful implantation in a patient with melas syndrome and demonstrates the ability to preoperatively confirm the integrity of brainstem and cortical auditory pathways despite significant CNS degeneration.- - - - - - - - - - ranking = 1keywords = acid (Clic here for more details about this article) |
2/72. Auditory neuropathy with preserved cochlear microphonics and secondary loss of otoacoustic emissions.Auditory neuropathy is defined as absent or severely distorted auditory brainstem responses with preserved otoacoustic emissions and cochlear microphonics. This entity can be found in various circumstances including pre-lingual children. An almost universal characteristic reported from adult patients is the ineffectiveness of traditional hearing aids. Adequate management of pre-lingual cases therefore remains an open problem. This paper describes two pre-lingual children whose follow-up data demonstrated a selective loss of the otoacoustic emissions, whereas the cochlear microphonics remained preserved. In one of the patients, hearing aid fitting as soon as she lost her otoacoustic emissions proved successful. These findings have important implications for the operational definition of the condition, since one must be prepared to encounter cases with absent otoacoustic emissions. The present data also demonstrate that conventional amplification can benefit pre-lingual auditory neuropathy cases, at least once they have lost their otoacoustic emissions.- - - - - - - - - - ranking = 2210.2717750869keywords = amplification (Clic here for more details about this article) |
3/72. Hereditary glomerulopathy associated with a mitochondrial tRNA(Leu) gene mutation.Several cases of hereditary glomerulopathy associated with an A to G transition at position 3243 in mitochondrial dna, which is known to be associated with most cases of melas syndrome (myopathy, encephalopathy, lactic acidosis, and stroke-like episodes), have been recently reported. These patients share the characteristics of hereditary progressive glomerular disease and hearing loss with Alport syndrome. We therefore screened 27 patients with kidney disease clinically mimicking Alport syndrome for the presence of the 3243 mitochondrial mutation, and found one girl with the mutation and a positive family history. Her clinical features were very similar to those of all cases reported to date. An absence of hematuria, severe kidney involvement in a female, pathological changes of focal segmental glomerulosclerosis with no basket-weave change of the glomerular capillary wall, and the frequent association of steroid-induced diabetes are the major features that distinguish this condition from Alport syndrome. Careful neurological examination may detect neuromuscular symptoms compatible with mitochondrial cytopathies. In conclusion, progressive glomerulopathy should be included in the broad spectrum of mitochondrial cytopathies, especially in cases of melas syndrome. This mutation should also be included in the etiologies of secondary focal segmental glomerulosclerosis and in the differential diagnosis of Alport syndrome.- - - - - - - - - - ranking = 1keywords = acid (Clic here for more details about this article) |
4/72. A connexin 26 mutation causes a syndrome of sensorineural hearing loss and palmoplantar hyperkeratosis (MIM 148350).We report a missense mutation in the connexin 26 gene (GJB2) in a family with an autosomal dominant syndrome of hearing loss and hyperkeratosis. The affected family members have high frequency, slowly progressive, bilateral, sensorineural hearing loss and palmoplantar hyperkeratosis. The mutation causes an amino acid substitution (G59A), which may disrupt a reverse turn in the first extracellular loop of connexin 26. Connexin 26 mutations have been reported in syndromes of deafness and palmoplantar keratoderma. These data provide additional evidence for the role of connexin 26 in syndromes of this type.- - - - - - - - - - ranking = 1keywords = acid (Clic here for more details about this article) |
5/72. cochlear implantation of auditory neuropathy.Auditory neuropathy (AN) is a hearing disorder that presents with a grossly abnormal or absent neural response as measured by evoked potentials in the presence of normal outer hair cell function evidenced by present otoacoustic emissions or cochlear microphonics. rehabilitation for patients with AN is challenging due to abnormal temporal encoding at the auditory nerve leading to severely impaired speech perception. Although patients with AN may demonstrate improvement in thresholds with amplification, temporal encoding dysfunction, and consequently speech perception degradation, is not alleviated by amplification. Another issue is the heterogeneity of the AN population in terms of audiologic and neurologic findings, in addition to uncertain etiology and pathophysiology. For children with prelingual onset of AN, development of auditory and oral communication skills is particularly compromised. All children with hearing loss in the severe-to-profound range who do not benefit from conventional amplification can be considered candidates for a cochlear implant (CI). This paper presents a case study of a child with AN who received a CI. Whereas no synchronous neural response auditory brainstem response could be elicited to acoustic stimuli, an electrically evoked auditory nerve action potential was evident following implantation, suggesting restoration to some degree of neural synchrony. Significant improvement in speech perception was found post-CI. Recommendation to implant all patients with AN would be premature, but these findings suggest that electrical stimulation in some cases of auditory neuropathy can be a viable option.- - - - - - - - - - ranking = 6630.8153252606keywords = amplification (Clic here for more details about this article) |
6/72. Long-term follow-up in distal renal tubular acidosis with sensorineural deafness.A 20-year-old man presented with failure to thrive and bilateral genu valgum. On the basis of growth failure, skeletal deformity, hyperchloremic metabolic acidosis with alkaline urine and hypokalemia, nephrocalcinosis, and hearing loss, a diagnosis of distal renal tubular acidosis (DRTA) with sensorineural deafness was made. The genu valgum was treated by corrective osteotomy. Skeletal deformity was corrected and impaired growth improved after sustained therapy of metabolic acidosis with alkali supplementation. During an 8-year follow-up period the patient's glomerular filtration rate remained stable, the nephrocalcinosis did not progress, and his height increased 10 cm. Although nephrolithiasis led to atrophy of the right kidney, at last follow-up, when the patient was 44 years old, his creatinine clearance was 50 ml/min per 1.73 m2 body surface.- - - - - - - - - - ranking = 7keywords = acid (Clic here for more details about this article) |
7/72. Sudden bilateral hearing loss and sporadic mitochondrial dna deletion.Several studies have indicated that a number of different mitochondrial dna (mtDNA) mutations may be responsible for human pathologies. Sensorineural hearing loss (SNHL) may be associated with known syndromes (syndromal SNHL) or represent the only manifestation of mitochondrial damage (non-syndromal hearing loss). Moreover, mtDNA alterations may be responsible for aminoglycoside-induced deafness. We describe a patient harbouring a single sporadic mtDNA deletion, who presented with sudden adult-onset bilateral, although non-simultaneous SNHL, that was partially responsive to corticosteroids. Increased values of rest, and exercise, blood lactic acid were decisive for diagnosis, prompting muscle biopsy that revealed the mtDNA deletion. The case underscores the importance of investigating a mitochondrial disease in cases of SNHL of unknown origin and points out the importance of an increased blood level of lactic acid as a screening test.- - - - - - - - - - ranking = 2keywords = acid (Clic here for more details about this article) |
8/72. Fitting low ratio compression to people with severe and profound hearing losses.OBJECTIVE: In this study, we aimed to determine the extent to which wide dynamic range compression and compression limiting could benefit severely and profoundly hearing-impaired adults. DESIGN: Subjects were fitted with multi-memory hearing aids incorporating frequency independent input-controlled compression with a 2:1 compression ratio and output-controlled compression limiting. The input compression threshold (CT) was varied to establish the lowest level that maintained audibility for conversational intensity speech without acoustic feedback oscillation. Where a low (40 to 57 dB SPL) CT was possible, this was compared with a moderate (65 to 74 dB SPL) level. The preferred input compression setting was subsequently compared with linear, compression-limited amplification in the same aids. In the three cases where 2:1 input compression could not be used, because of feedback or loudness insufficiency problems, compression limiting was compared with peak clipping. Field trials were conducted over a 2- or 3-mo period to establish preferences. RESULTS: Nine of the 16 subjects preferred the inclusion of the higher level input compression, and one preferred lower level input compression. Four subjects preferred linear, compression-limited amplification, one favored peak clipping, and one could not be satisfied with any of the options provided. CONCLUSIONS: 2:1 input compression was useful, and preferred by 10 of the subjects, but for nine subjects the preferred CT was relatively high. With a group 4-frequency average loss of 87 dB HTL, the results demonstrate that fast-acting, low compression ratio systems can be useful for losses traditionally regarded as the domain of linear amplification.- - - - - - - - - - ranking = 6630.8153252606keywords = amplification (Clic here for more details about this article) |
9/72. Spontaneous recovery of profound post-meningitic hearing loss.The timing of insertion of a cochlear implant (CI) in post-meningitic sensorineural hearing loss is, in spite of recent advances in the understanding of the pathogenesis of the condition, still controversial. The danger of labyrinthitis ossificans allows only a little time to decide whether to implant a CI or not. On the other hand the clinician needs to be certain that no residual hearing is present and whether or not the patient will benefit from conventional amplification. A well-documented case of early spontaneous recovery of a profound post-meningitic sensorineural hearing loss in a child is presented and the relevant literature reviewed.- - - - - - - - - - ranking = 2210.2717750869keywords = amplification (Clic here for more details about this article) |
10/72. arthrogryposis, renal dysfunction and cholestasis syndrome.We report for the first time from the Arabian Gulf area 3 patients with arthrogryposis multiplex congenita, cholestasis and renal tubular dysfunction from a Saudi family with 2 other siblings and 3 cousins who possibly died with a similar clinical picture. We also document for the second time in literature other findings in this syndrome including cerebral abnormalities (hypoplastic corpus callosum), congenital heart disease and nerve deafness. We suggest that some of these cases might benefit from ursodeoxycholic acid therapy. We believe that this autosomal recessive disorder is possibly under-diagnosed in this region with a high consanguineous marriage rate.- - - - - - - - - - ranking = 1keywords = acid (Clic here for more details about this article) |
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