The use of osseointegration of hearing aids

The principles of osseointegration defined by Branemark are reviewed. The authors describe the otological applications of titanium implants: bone anchored hearing aids (BAHA). The good results obtained depend on the selection of the patients and the observance of a rigorous surgical technique. The present paper summarizes our results with 32 BAHA implanted in 27 patients.     

Bone conduction implants for amplification: comparison of results

We compared the results from the North American patient database on the Xomed Audiant Bone Conductor to those reported on the NobleBiocare (previously Noblepharma) HC200 bone-anchored hearing aid (BAHA) implant, using the literature and specific results provided by one of the authors. It has been proposed that the percutaneous coupling of the NobleBiocare implant transduces energy more powerfully than the Audiant transcutaneous coupling. If true, percutaneous coupling could provide greater amplification, helping patients experiencing both conductive and sensorineural hearing loss. Aided sound-field thresholds corresponding to bone-conduction thresholds were compared retrospectively through the speech frequencies. Both the BAHA and the Audiant devices amplified in the sound field to approximate preoperative bone-conduction thresholds. No statistically significant differences existed between the amplification of warble tones through the speech frequencies for either device. We conclude that amplification with the Audiant device offers as much gain as the HC200 device through the speech frequencies. While both devices can supply effective amplification for select patients suffering from conductive hearing loss, neither provides gain superior to preoperative bone-conduction thresholds to address the needs of select patients with a substantial sensorineural component.     

Perceived sound quality of three bone-anchored hearing aid models

Eighteen patients judged the sound quality of the new Classic 300 and the existing HC 100 or HC 200 on 4 five-stage sound quality scales. Two of the scales relate to the perceptual dimensions softness and clarity, one relates to interference or noise and one relates to the overall impression. The evaluations were made, based on a questionnaire, in the patients' own homes and comprised the listening situations: TV news, music, conversation with two to three people in a noisy environment and one optional choice. The patients also stated which hearing aid was best in each situation and made a confidence rating for their selection. The patients were accustomed to wearing the HC 100 or HC 200. In these comparisons of the different bone-anchored hearing aid models, the Classic 300 received the best ratings overall. Seventeen patients changed their previously fitted hearing aid to a Classic 300 and satisfactory sound quality was undoubtedly one of the principal reasons. When it came to the confidence rating for their selections, some two-thirds of the patients stated that it was without hesitation or with little hesitation. Our overall conclusion is that the sound quality of bone-anchored hearing aids is satisfactory when it comes to clarity and overall impression. However, it may be expected that these patients with conductive losses get a better sound quality than other patients with sensorineural losses if the same type of aid is used.     

3 cases of post-stapedectomy labyrinthine fistula

Three cases are presented of labyrinthine fistula which suddenly arose in patients who had undergone stapedectomy interposing a vein graft from the back of the hand. These patients had all enjoyed 12-15 years apparently problem free period before the fistula occurred. In all three cases the fistula was accompanied by objective dizziness and varying degrees of sensorineural or mixed hearing loss. The patients underwent revision surgery which identified the fistula and the endolymph oozing out of the graft from the previously installed prosthesis. The authors present the cases, describe how the symptoms arose and the results obtained with revision surgery. Finally, they discuss the need to first perform stapedotomy with a platinar hole; they indicate that the number of cases of total or partial stapedectomy should be limited only to those cases characterized by anatomical variations and/or whenever complications arise during surgery.     

Association of thin basement membrane nephropathy with hypercalciuria, hyperuricosuria and nephrolithiasis

BACKGROUND: Familial persistent microhematuria with normal renal function is the most common presentation of thin basement membrane nephropathy (TBMN). Gross hematuria episodes and loin pain attacks are other manifestations of the disease. On the other hand, it has been shown that hypercalciuria (HC) and hyperuricosuria (HU) can produce both gross or microscopic non-glomerular hematuria, in addition to their role in renal stone formation. METHODS: We studied the prevalence of HC, HU and nephrolithiasis in a group of 27 biopsy-proven TBMN as well as in 19 non-biopsied first-degree relatives with persistent microhematuria and 25 first-degree relatives without microhematuria. A group of 27 patients with IgA nephropathy (IgAN) and persistent microhematuria, and another group of 20 healthy subjects without known renal diseases were selected as control groups. RESULTS: Ten (37%) patients with TBMN and 8 (42%) relatives with microhematuria showed HC and/or HU at presentation; relatives without microhematuria, IgAN patients and normal controls showed a significantly lower prevalence of HC and HU. The prevalence of previous nephrolithiasis among TBMN patients (25%) was significantly higher than in IgAN patients (3%; P < 0.05). Family history of nephrolithiasis was recorded in 14 (51%) of the 27 TBMN families, in contrast with 2 of 27 (7%) with IgAN and 1 of 20 (5%) in normal controls (P < 0.05). The prevalence of nephrolithiasis, gross hematuria bouts and loin pain episodes among TBMN patients and microhematuric relatives showing HC and/or HU at presentation (44%, 44% and 27%, respectively) were significantly higher than those of TBMN patients and microhematuric relatives with normal calcium and uric acid urinary excretions (10%, 7% and 3%, respectively; P < 0.05). At the end of follow-up (8.8+/-4.1 years in TBMN patients and 9.1+/-4.2 years in relatives with microhematuria), all the cases maintained normal renal function. CONCLUSIONS: We found a high prevalence of HC, HU, and nephrolithiasis among TBMN patients and relatives with microhematuria. Our study also shows a significant relationship between the presence of HC and/or HU and the prevalence of nephrolithiasis, gross hematuria bouts and loin pain episodes.     

Osseointegration enhanced by chemical etching of the titanium surface. A torque removal study in the rabbit

Roughened implant surfaces are thought to enhance osseointegration. Torque removal forces have been used as a biomechanical measure of anchorage or osseointegration in which the greater forces required to remove implants may be interpreted as an increase in the strength of osseointegration. The purpose of this study was to compare the torque resistance to removal of screw shaped titanium implants having an acid etched (HC1/H2SO4) surface (Osseotite) with implants having a machined surface. Two custom screw shaped implants, 1 acid etched and the other machined, were placed into the distal femurs of 10 adult New Zealand White rabbits. These implants were 3.25 mm in diameter x 4.00 mm in length without holes, grooves or slots to resist rotation. Following a 2 month healing period, the implants were removed under reverse torque rotation with a digital torque measuring device. Two implants with the machined surface preparation failed to achieve osseointegration. All other implants were found to be anchored to bone. Resistance to torque removal was found to be 4 x greater for the implants with the acid etched surface as compared to the implants with the machined surface. The mean torque values were 20.50 +/- 6.59 N cm and 4.95 +/- 1.61 N cm for the acid etched and machined surfaces respectively. The results of this study suggest that chemical etching of the titanium implant surface significantly increases the strength of osseointegration as determined by resistance to reverse torque rotation.     

Deafness secondary to lumbar puncture

INTRODUCTION AND OBJECTIVE: Disorders of hearing have been described in patients who have undergone lumbar puncture. The lower frequencies are most affected, temporarily and with spontaneous recovery in most cases. It would seem that the cochlea aqueduct (AC) (an anatomical structure found in the internal ear) is the part involved in the pathogenesis of this infrequent complication. The object of this paper is to review the different hypothesis put forward by various authors on the subject, emphasizing the one which seems most probable. At the same time, we offer a new vision of this little known and often forgotten anatomical structure of the internal ear. The anatomy and physiology of the AC is considered, studying the part played by the labyrinth fluid when the patient undergoes an operation involving the cerebro-spinal fluid (CSF) or the subarachnoid space. CONCLUSIONS: Whenever this technique is to be used, it is essential to obtain a clinical history to find out whether the patient has, or has had, any problems of hearing, and if so of what type. All patients should be warned of the possibility of deafness, in most cases temporary, and if the patient has hydrops endolymphaticus (syndrome of Ménière) of the high risk of worsening his hearing threshold. We therefore recommend precise evaluation of the use of this technique.     

Bilateral loss of vestibular function: clinical findings in 53 patients

The clinical presentations and aetiologies of a series of 53 cases of bilateral vestibular failure (BVF) seen by the authors over a decade were evaluated by retrospective review of the medical records. Thirty-nine per cent of patients had associated neurological disease; 13% had a progressive cerebellar syndrome with disabling gait ataxia, abnormal eye movements and cerebellar atrophy on neuro-imaging. BVF was usually unsuspected. Nine per cent had cranial or peripheral neuropathies and in this group there was no abnormality of brain stem/cerebellar oculomotor function, but hearing loss was common. Eleven per cent revealed BVF and hearing loss secondary to meningitis, and 6% had other neurological disorders. Idiopathic BVF was found in 21% of cases, characterised by paroxysmal vertigo and/or oscillopsia, but no abnormal clinical signs. Gentamicin ototoxicity accounted for a further 17%, while autoimmune disease was present in 9% of patients. Otological or neoplastic disease was diagnosed in the remaining 13% of patients. It was concluded that neurological, audiological and ocular motor assessments allow the probable cause of BVF to be defined in approximately 80% of cases. A group of BVF related to autoimmune pathologies is reported for the first time, indicating the need for immunological screening. Idiopathic BVF may present with only minor visual or vestibular symptoms, while in patients with cerebellar degeneration, BVF may be unsuspected and, thus, underdiagnosed.     

Preferred CDRH3 lengths for antibodies with defined specificities

OBJECTIVES/HYPOTHESIS: To compare early (<1 y) and longer-term (1.0-7.5 y; mean follow-up, 2.8 y) hearing results following surgery for congenital aural atresia and to analyze revision cases for cause of failure, time of occurrence, and outcome. STUDY DESIGN: Retrospective study of 55 consecutive patients (59 ears) undergoing surgery during an 11-year period for congenital aural atresia. METHODS: The best speech reception threshold (SRT) during the first postoperative year was compared with the most recent SRT beyond the first postoperative year. The complication rate and long-term hearing results (>1 y) for initial and revision surgeries were compared. RESULTS: In the early postoperative period, an SRT of < or =25 dB was achieved in 60% and an SRT of < or =30 dB in 70%. With longer follow-up (mean, 2.8 y), 46% of patients maintained an SRT < or =25 dB. Revision surgery was necessary in approximately one third of patients. Longer-term hearing results following initial surgery only or after revision surgery showed an SRT < or =25 dB in 53% and an SRT < or =30 dB in 64%. For primary and revisions surgeries the incidence of temporary facial paralysis was 1.5% and for significant hearing loss, 3.0%. CONCLUSIONS: Some degradation in hearing does occur as patients are followed beyond the first postoperative year. Revision surgery will be necessary in approximately one third of cases. With revisions, an SRT < or =25 dB can be expected in half of cases and an SRT < or =30 dB in two thirds of cases. The ability to provide these hearing results supports this surgery in unilateral cases.     

Preservation of hearing in large acoustic neurinomas following removal via suboccipito-lateral approach

A consecutive series of 61 patients with pre-operative hearing underwent surgical removal of a large acoustic neurinoma via the lateral suboccipital approach between 1984 and 1996. Brain-stem auditory evoked potentials (BAEP) were present in all cases before surgery and all patients underwent intra-operative monitoring of BAEP. The average tumour size including the portion within the meatus acusticus internus was 30, 5 mm (range 20 mm-49 mm). Complete tumour removal was achieved in all but three cases. In 43.1% of patients with complete tumour removal hearing was preserved initially after surgery. Delayed postoperative hearing loss was observed in 11 patients and hearing recovery in 2 patients leading to 27.5% definite hearing preservation. Hearing preservation was achieved in 37% of cases with tumour size between 20 mm-29 mm and in 23.5% of case with tumour size larger than 30 mm. These results indicate that even in large neurinoms hearing preservation should be attempted in all patients with documented pre-operative hearing and BAEP.     

Active electronic cochlear implants for middle and inner ear hearing loss--a new era in ear surgery. I: Basic principles and recommendations on nomenclature

Hearing aids have fundamental disadvantages: (1) stigmatization of the patient; (2) the sound is often found to be unsatisfactory due to the limited frequency range and undesired distortion; (3) in many patients, the ear canal fitting device generally necessary leads to an occlusion effect; (4) acoustic feedback when amplification is high. Conventional hearing aids transmit sound into the ear canal via a small microphone. Sound has the disadvantage of requiring high output sound pressure levels for its transmission. This along with the necessary miniaturization of the loudspeaker as well as the resonances and reflections in the closed ear canal contribute to the disadvantages mentioned. In contrast, implantable hearing aids do not make sound signals but micromechanical vibrations. An implantable hearing aid has an electromechanical transducer instead of the loudspeaker of a conventional hearing aid. The hearing signal does not leave the transducer as sound but as a mechanical vibration which is directly coupled to the auditory system bypassing the air. This implantable hearing aid is either coupled to the tympanic membrane, the ossicular chain, the perilymph of the inner ear, or the skull. An implantable hearing aid is expected to have: 1 Better sound fidelity than a hearing aid 2 No ear canal fitting device, free ear canal 3 No feedback 4 Invisibility Requirements on electronic hearing implants designed for patients with conductive hearing loss differ from those on implants for sensorineural hearing loss. Conductive hearing loss requires the implant to replace the impedance transformation, thus being an impedance transformation implant (ITI). In various respects, the demands on an ITI are lower than the demands on an electronic hearing aid for patients with sensorineural hearing loss. The latter are mostly patients with a failure of the cochlea amplifier (CA). A damage to the CA is clinically discernible by a positive recruitment and loss of otoacoustic emissions (OAE). Since these patients form the majority of cases with sensorineural hearing loss, an active hearing implant for such patients should partially replace the function of the CA. Therefore, the suggestion is to refer to a CAI (cochlea amplifier implant). The implant expressions ITI (for patients with conductive hearing loss) and CAI (for patients with sensorineural hearing loss) used in this context allow nomenclatural association with the CI (cochlear implant) for complete inner ear failure as well as with the BSI (brainstem implant) in the case of hearing nerve failure.     

Hippocampal involvement in the acquisition of relational associations, but not in the expression of a transitive inference task in mice.

The hippocampus (HC) has been suggested to play a role in transitive inference (TI) on an ordered sequence of stimuli. However, it has remained unclear whether HC is involved in the expression of TI, or rather contributes to TI through its role in the acquisition of the sequence of elements (Frank, Rudy, & O'Reilly, 2003). Presently, the authors compared the effects of excitotoxic dorsal HC lesions in C57BL mice that received surgery before or after they were trained to discriminate between pairs of visual stimuli. Performance on a subsequent TI task was worse in mice with pretraining lesions than in those with posttraining lesions, which showed similar performance to shams without lesions. This indicates that HC is not involved in the expression of TI, but may merely help to acquire the underlying representations required for TI. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age- and strain-related differences in dehydrogenase activity and glycogen levels in CBA and C57 mouse cochleas

In the C57 mouse strain, loss of sensory hair cells (HCs) begins during early adulthood, starting in the base of the cochlea and progressing toward the apex as aging continues. In contrast, the CBA mouse strain exhibits no significant cochlear histopathology until relatively late in life. These strain and age differences may be related to differences in cochlear energy metabolism. To examine this possibility, we used dehydrogenase and glycogen histochemistry to evaluate the metabolic capacities of HCs and stria vascularis (SV) in cochleas of C57 and CBA mice. Reaction product density was quantified and compared as a function of strain (1.5-month-old C57 mice vs. CBA mice) and age (CBA mice, 1.5, 18 and 36 months). Young C57 mice had significantly less HC dehydrogenase activity than CBA mice of any age, lower HC glycogen levels than 18-month-old CBA mice and lower SV glycogen levels than 18- or 36-month-old CBA animals. Within the CBA strain, HC dehydrogenase activity decreased significantly between 1.5 and 18 months of age, while glycogen levels in both HCs and SV increased over the same time period. Between 18 and 36 months, HC dehydrogenase activity and SV glycogen levels remained stable. The results show that there are significant age-related changes in energy metabolism in the inner ear of CBA mice that are correlated with age-related hearing loss. Genetically determined deficits in cochlear metabolic capacity in C57 mice could be linked to the early onset of hearing loss in this strain.     

Computerized tomography in children and adolescents with suspected petrous bone abnormality

PURPOSE: To demonstrate HRCT findings and their therapeutic relevance in suspected congenital hearing disorders. MATERIAL AND METHODS: It was checked in 96 young patients if HRCT findings of the temporal bone could explain functional findings. Furthermore, the therapeutic consequences were noted. RESULTS: Normal CT and normal functional findings were obtained in 49 temporal bones (TB). In conductive hearing loss (41 TB), dysplasias of the conducting apparatus (37 TB) and inflammatory changes (3 TB) were found. Combined hearing loss (18 TB) was clarified completely or partially in half the cases. There were 22 dysplasias of the inner ear, 3 dysplasias of the middle ear, 1 abandoned examination (2 TB), and 55 normal CT findings in senorineural hearing disorders (82 TB). 1 retardate had a malformation of the inner ear and, contralaterally, inflammatory middle ear. In cases of vestibular disorders (24 TB), 14 malformations of the inner ear were detected. An indication for an operation was given in 23 TB. In 22 TB, it was contraindicated. The CT was one preliminary examination to a cochlea implant in 19 patients. The therapy was carried on with hearing devices in the other patients. CONCLUSION: HRCT is an important method in diagnosis and therapeutic planning of suspected malformations of the temporal bone.     

Renal tubular dysfunction after urinary diversion

Renal tubular function can be assessed by measuring low molecular weight proteins in urine. In the present study, urinary levels of protein HC, also called alpha 1-microglobulin, were determined in 84 patients, 3-17 years after conduit diversion or continent urinary reconstruction. Increased excretion of protein HC, indicating tubular dysfunction, was found in 30 patients (36%), but was slight in most cases. Among patients with GFR > 45 ml/min/1.73 m2 at latest follow-up, the fall from preoperative GFR was greater in those with elevated levels of protein HC than in those with normal levels (p < 0.01). No permeation of protein HC through the intestinal mucosa in contact with urine could be demonstrated. Urinary protein HC may be a suitable marker for detecting early renal impairment after urinary diversion.     

Schwannoma with sweat duct differentiation

In a randomized trial of second line hormone therapy 56 postmenopausal women with advanced breast cancer received low dose aminoglutethimide (AGT) 125 mg twice daily without hydrocortisone (27 patients), or hydrocortisone (HC) 20 mg twice daily (29 patients). The two groups were well-matched for previous response to tamoxifen (TAM) therapy (AGT (35%) vs HC (32%)) and for relapse on adjuvant TAM. The mean age of the two groups was 69.2 years (AGT) and 63.2 years (HC). Liver metastases were present in 29% (AGT) and 33% (HC). The response rates were 11% (AGT) and 21% (HC). At 12 months the failure of treatment rate was 80% (AGT) and 70% (HC). Survival at 12 months was 50% for both groups. At 12 months 5/12 survivors were still on AGT and 8/12 on HC. These preliminary findings have so far failed to show any statistical difference in tumour response, time to treatment failure or survival between low-dose AGT and HC as second-line hormone treatment post-tamoxifen in advanced breast cancer.     

Summary of the guideline 'Hearing impairement' from the Dutch College of General Practitioners. The Dutch College of General Practitioners

Hardness of hearing is a growing problem; toward the year 2000 there will be 1.5 to 2 million persons with hardness of hearing in the Netherlands. The Dutch College of General Practitioners has published a guideline 'Slechthorendheid' [hardness of hearing] with instructions for the diagnosis and treatment of patients with hardness of hearing in primary care. Many patients with hardness of hearing do not visit the GP (e.g. mentally handicapped). The whispered speech test or screening audiometry plays an important part in the diagnosis. In case a hearing loss > or = 30 dB is detected consultation of or referral to an ENT specialist is an option. In most cases a plug of earwax is the cause of the hardness of hearing.     

Verbal and nonverbal memory processing in patients with obsessive-compulsive disorder: Its relationship to clinical variables.

Memory deficits have been reported in several neuropsychological studies of obsessive-compulsive disorder (OCD). Dysfunction in nonverbal memory has been consistently reported, whereas findings on verbal memory are more heterogeneous. The authors studied 50 patients with OCD who were matched for sex, age, educational level, and hand dominance with 50 healthy controls (HC). Cognitive performance in both groups was assessed on verbal and nonverbal memory tasks, and several clinical variables were also assessed in the patient group. Patients with OCD showed a pattern of cognitive dysfunction with alterations in areas of nonverbal memory (recall and recognition), and verbal memory (learning and recall). Older age at onset of OCD was associated with poorer performance on verbal memory tasks. Low scores on some verbal memory tasks were associated with severity of OCD, and nonverbal memory was influenced by depressive symptoms. The study suggests the existence of dysfunction in the execution of verbal and nonverbal memory tasks in OCD; the influence of clinical variables depends on the specific neuropsychological function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ultrastructural observation of platelets from patients with progressive systemic sclerosis (PSS)

We observed the ultrastructure of platelets from patients with PSS (7 cases; 48.2 +/- 12.3 y-old; M:F = 1:6_ and healthy controls (HC) (5 cases; 44.8 +/- 8.0 y-old; M:F = 1:4) by using transmission (TEM) and freeze-fracture electron microscopy (FEM). The open canalicular system (OCS) connected with the plasma membrane (PM) formed pinhole-like invaginations (50 nm in diameter) in the cleaved face (P-face) of the plasma membrane seen from the outside of the platelets and sharply elevated structures in the cleaved face (E-face) of PM seen from the inside of the platelets by FEM. The density of OCS on the surface of the platelets from PSS patients was 3 +/- 1/micron 2, which was higher than that from HC (1 +/- 0.5/micron 2) (p < 0.02). Dome-shaped structures, which clearly differ from OCS and were 80-150 nm in diameter without intramembranous particles, were seen in the P-face, and the complementary depressed structures were seen in the E-face. These structures were thought to be vesicles fused onto the PM of the platelets. The total volume of platelets (7.62 +/- 0.11 micron 3), total volume of granules (0.79 +/- 0.01 micron 3) and vacuoles including OCS (0.78 +/- 0.05 micron 3), and the total surface area of platelets (17.25 +/- 1.30 micron 2) from four PSS patients calculated by the morphometrical method were similar to those from four HC (7.32 +/- 0.25 micron 3, 0.76 +/- 0.03 micron 3, 0.80 +/- 0.05 micron 3, 18.75 +/- 0.35 micron 2, respectively); there were no statistical significances between the data from PSS patients and HC. The total volumes of vacuoles in platelets from both PSS patients and HC significantly decreased after a 2 min-vibration stress of the hands (p < 0.02) and the total volume of granules in platelets from PSS patients decreased significantly after the same stress (p < 0.002), although that from HC showed no similar significant change. However, there were no statistically significant differences in total volume or total surface of platelets from PSS patients and HC after the stress. These data may suggest that depletion of granules occurred due to activation of platelets from PSS patients following a secretion of their proteins, because their plasma protein levels were elevated after the stress (Jpn J Dermatol, 98; 1205, 1988). Higher density of OCS on the surface of the platelets from PSS patients may play an important role in secretion of their proteins, although the detailed mechanism of secretion of specific proteins derived from platelet granules is still unknown. These ultrastructural abnormalities of platelets may correlate with some involvement of a platelet disorder and with a possible role for the activation of platelets from PSS patients.     

So close, and yet so far: Does collectivism foster transparency overestimation?

The present research demonstrated that horizontal collectivism (HC), the tendency to emphasize social bonds and interdependence, is associated with overestimating the extent to which one's preferences, feelings, and behavioral inclinations are transparent to close others. The link between HC and felt transparency was mediated by self-other merging but was not significantly mediated by perceived similarity, behavioral closeness, or metaperception positivity. Evidence of a causal connection was obtained in an experiment where individuals for whom interdependence was primed exhibited greater transparency overestimation than did those for whom it was not. Additional results indicated that higher HC is associated with greater confidence but not greater accuracy in judgments about a friend. The authors argue that other perspective-taking deficits involving overuse of the self in judgments of others should also be exacerbated by the self-other merging that is associated with HC. (PsycINFO Database Record (c) 2010 APA, all rights reserved)