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PubMed2006

Divergence of fine and gross motor skills in prelingually deaf children: implications for cochlear implantation.

OBJECTIVE: The objective of this study was to assess relations between fine and gross motor development and spoken language processing skills in pediatric cochlear implant users. STUDY DESIGN: The authors conducted a retrospective analysis of longitudinal data. METHODS: Prelingually deaf children who received a cochlear implant before age 5 and had no known developmental delay or cognitive impairment were included in the study. Fine and gross motor development were assessed before implantation using the Vineland Adaptive Behavioral Scales, a standardized parental report of adaptive behavior. Fine and gross motor scores reflected a given child's motor functioning with respect to a normative sample of typically developing, normal-hearing children. Relations between these preimplant scores and postimplant spoken language outcomes were assessed. RESULTS: In general, gross motor scores were found to be positively related to chronologic age, whereas the opposite trend was observed for fine motor scores. Fine motor scores were more strongly correlated with postimplant expressive and receptive language scores than gross motor scores. CONCLUSIONS: Our findings suggest a disassociation between fine and gross motor development in prelingually deaf children: fine motor skills, in contrast to gross motor skills, tend to be delayed as the prelingually deaf children get older. These findings provide new knowledge about the links between motor and spoken language development and suggest that auditory deprivation may lead to atypical development of certain motor and language skills that share common cortical processing resources.

Age Factors↗

PubMed2004

[Navigation-controlled cochleostomy. Is an improvement in the quality of results for cochlear implant surgery possible?].

BACKGROUND: The correct positioning of the electrode, which is the limiting factor for the functional integrity of cochlear implants, is decisively influenced by the cochleostomy. Localisation and form of the drilling canal have been solely defined by the surgeon during the operation and an enlargement of the drilling canal is often necessary. Thanks to the improved resolution of new slice imaging techniques, computed tomography allows an exactly defined optimal point for cochleostomy. MATERIAL AND METHODS: In a cadaver study, we examined whether the target defined with computed tomography can be reached in a reproducible way with the help of navigated computer assisted surgery. We chose titanium screw markers as the gold standard for referencing. RESULTS: There was a real deviation of 1.6 mm in the target field. Thus, in a cochleostomy with a diameter of 0.5 mm the goal was not reached in a reproducible way. With this deviation a target of 2.56 mm(2) is defined. CONCLUSIONS: A target assessed by navigation is better than one reached without navigation in view of reproducibility and accuracy. With further technical progress navigated cochleostomy will be possible.

Cadaver↗

PubMed1987

Cochlear implant candidates: assessment with CT and MR imaging.

Eighty-seven patients with severe to profound hearing loss were evaluated for possible placement of a multichannel cochlear implant hearing device. After initial clinical screening, 42 patients underwent computed tomographic (CT) examination. Five of these patients were also examined with magnetic resonance (MR) imaging. Twenty-two patients received implants. CT of the middle and inner ear was normal in 24 patients (57.1%) and showed labyrinthine ossification in 12 (28.6%), cochlear or fenestral otosclerosis (or both) in four (9.5%), and congenital cochlear malformation in two (4.8%). The information provided by CT was used to (a) exclude patients in whom multichannel cochlear implantation would most likely be unsuccessful (owing to obliterative labyrinthine ossification, or congenital cochlear malformation, severe cochlear, or fenestral otosclerosis), (b) help select the best ear for implantation, and (c) provide a preoperative picture of normal variants and avoidable surgical pitfalls. MR experience is limited but assessment of the size of the cochlear nerve and the membranous labyrinth is possible with this modality and may provide additional information in the evaluation of these patients.

Adolescent↗

PubMed2006

Cochlear implantation of patients with far-advanced otosclerosis.

OBJECTIVE: This current single-subject, repeated-measures study was to describe our experience with 30 patients who had been diagnosed with "far-advanced otosclerosis" and who were included in our program of cochlear implants. We analyzed the history of the patients and their families before implantation, the surgical findings, and the performance over a follow up of 3 years. MATERIAL AND METHODS: All patients met one or more of the after criteria: 1) previous surgical intervention as a treatment of their otosclerosis; 2) signs of pericochlear hypodensities in high resolution computed tomography (HRCT) scans; and 3) family precedents of otosclerosis. All underwent standard surgical cochlear implantation. RESULTS: In 78% of the cases, a stapedectomy had previously been realized. Cochlear otosclerosis could be appreciated in HRCT in 78% of the patients. A family history of otosclerosis was found in 40%, and 33.3% of patients had familial precedents of nonfilial hypoacusis. The mean results in the two-syllable test were 20% preimplantation, 54% 6 months after implantation, and 52%, 62%, 54% at 1, 2, and 3 years after implantation. In the CID sentence test, they were in the order of 32% preimplantation and of 64% at 6 months, 66% after 1 year, of 68% after 2 years, and reaching 72% after 3 years. No complications related to the surgery were detected. CONCLUSION: Patients diagnosed with far-advanced otosclerosis have a good prognosis with cochlear implantation comparable to that of other patients in whom postlingual implants are performed.

Adult↗

PubMed1999

Investigation of the effects of temporal and spatial interactions on speech-recognition skills in cochlear-implant subjects.

Forward masking was investigated as a measure of spectral and temporal interactions. Such interactions may adversely affect speech recognition in cochlear-implant subjects. Seven subjects, implanted with the Nucleus 22 device, performed a forward-masking task. They also performed an electrode-discrimination task in order to measure spectral interactions without temporal interactions. Correlation analysis indicated a significant relationship between data obtained in the two tasks (p < 0.1). The two tasks were also correlated with the subjects' scores from five measures of speech recognition. Forward masking and electrode discrimination were strongly correlated with measures requiring consonant and phoneme recognition, respectively. These results indicate that the relationship between forward masking and speech recognition may be due, in part, to a lack of spectral resolution. The data also indicate that consonants may be more readily masked than vowels. Forward-masking data measured for all clinically programmed electrodes in three of the seven subjects were used with a model of the spectral maxima sound processor (SMSP) to estimate the number of electrodes stimulated during a consonant that might be masked by prior presentation of a vowel. These results suggest that temporal interactions across electrodes may be a factor in speech-recognition abilities of some cochlear-implant subjects.

Adult↗

PubMed1996

Acquisition of speech, pre- and post-cochlear implantation: longitudinal studies of a congenitally deaf infant.

This paper details the process of speech acquisition by the first British, congenitally deaf infant (without additional handicaps) to be fitted with a multi-channel cochlear implant. The infant's phonologic and phonetic level development using, firstly, acoustic hearing aids and, secondly, a cochlear implant, is thoroughly detailed by use of video- and audio-recorded data, taken at weekly intervals and across a variety of contexts. The paper examines the benefit of early implantation for spoken language development and notes the utility of Ling's model of speech acquisition for the habilitation of young, congenitally deaf implant recipients.

Cochlear Implants↗

PubMed2005

Cochlear implant outcome is not influenced by the choice of ear.

OBJECTIVES: This study tested the hypothesis that patients with residual hearing in the nonimplanted ear had the same cochlear implant benefit whether the implanted ear had profound or severe hearing loss. DESIGN: A retrospective chart review of adult cochlear implant recipients with postlingual hearing loss. Patients were categorized according to the pure-tone average of the implanted and contralateral ears as (a) bilateral profound, (b) severe-profound, and (c) bilateral severe. The results of a test battery of spoken language measures were compared among patients belonging to these hearing categories at 6, 12, and 24 months after surgery, using a t-test and multivariate regression analyses. RESULTS: The presence of residual hearing in one or both ears was associated with significantly higher postoperative speech perception scores compared with participants with bilateral profound hearing loss. Among participants with similar amounts of residual hearing in the nonimplanted ear, however, there was no difference in speech recognition scores between those with profound and those with severe hearing loss in the implanted ear. CONCLUSIONS: Among participants with asymmetric hearing loss, there is no additional benefit to implanting the better-hearing ear that can be preserved for use with a hearing aid for better speech understanding in noise and sound localization. These results suggest that the additional benefit received by patients with residual hearing is mediated by trophic effects on crossed pathways in the central nervous system and is independent of the preoperative functional status of the implanted ear.

Adult↗

PubMed1996

Cochlear implants in prelingually deaf children.

All private and public residential and day schools for the deaf in the U.S. that have 100 or more students were surveyed to see how many prelingually deafened students they had with cochlear implants and how many of these students were still using the device. Responses came from 70% (45 of 64) of those schools surveyed. Of the 151 implanted children identified, 71 (47%) were no longer using the cochlear implant. Of the remaining 80 children (53%) still wearing the device, we could not specifically determine by survey the percentage who derived significant benefit from the device and the percentage who did not. However, numerous comments by those returning the questionnaires indicated despondency over the results of the implant.

Child↗

PubMed1993

The perception of temporal modulations by cochlear implant patients.

The perception of temporal modulations of pulsatile electric stimuli was measured in seven cochlear implant patients using the Cochlear Pty. Limited prosthesis. Four patients were postlingually deafened adults and three patients were young adults who were deafened very early in life. The first study measured detection thresholds for modulated pulse duration for a series of modulation frequencies and pulse rates. The shape of the detection thresholds as a function of modulation frequency, the temporal modulation transfer function, often resembled a low-pass filter with a 50-100-Hz cut-off frequency. Thresholds did not markedly vary across the different pulse rates for most patients. Thresholds were less than 10%-20% of the range of usable hearing for most patients. The second study compared detection thresholds for modulated pulse durations around different reference pulse durations: 50, 100, and 300 microseconds. Detection thresholds were generally proportional to the different reference pulse durations. The third study measured difference limens for the discrimination of modulation depth. The difference limens were similar to the detection thresholds for the same reference pulse duration and pulse rate. The three patients deafened very early in life showed more within-group variation in performance, and their overall levels of performance were poorer than those of the postlingually deafened adults.

Acoustic Stimulation↗

PubMed1994

Determination of the position of nucleus cochlear implant electrodes in the inner ear.

Accurate determination of intracochlear electrode position in patients with cochlear implants could provide a basis for detecting migration of the implant and could aid in the selection of stimulation parameters for sound processor programming. New computer algorithms for submillimeter resolution and 3-D reconstruction from spiral computed tomographic (CT) scans now make it possible to accurately determine the position of implanted electrodes within the cochlear canal. The accuracy of these algorithms was tested using an electrode array placed in a phantom model. Measurements of electrode length and interelectrode distance from spiral CT scan reconstructions were in close agreement with those from stereo microscopy. Although apparent electrode width was increased on CT scans due to partial volume averaging, a correction factor was developed for measurements from conventional radiographs and an expanded CT absorption value scale added to detect the presence of platinum electrodes and wires. The length of the cochlear canal was calculated from preoperative spiral CT scans for one patient, and the length of insertion of the electrode array was calculated from her postoperative spiral CT scans. The cross-sectional position of electrodes in relation to the outer bony wall and modiolus was measured and plotted as a function of distance with the electrode width correction applied.

Adult↗

PubMed1994

The Vienna Cochlear Implant in patients with obliteration of the cochlea.

Twelve deaf patients with obliterated or ossified cochleas received the extracochlear version of the Vienna Cochlear Implant. Four patients, 1 of them a child, developed open speech comprehension. Obliteration of the cochlea could not always be predicted by conventional tomography of the temporal bone. Short duration of deafness, wide dynamic range, and good ability of time resolution (small temporal difference limen [TDL]) are predictors for good postoperative results. Obliteration or ossification of the cochlea per se is no contraindication to cochlear implantation.

Adult↗

PubMed2000

Electrode discrimination and speech perception in young children using cochlear implants.

OBJECTIVE: The aim was to determine the efficacy of a child-appropriate procedure to assess electrode discrimination ability in young children using cochlear implants and to investigate the relationship of electrode discrimination ability and speech perception performance in children implanted at a young age. DESIGN: An adaptation of the play audiometry procedure was used to assess electrode discrimination in seventeen 4- to 10-yr-old children. The children were required to respond with a game-like motor response when a repeating stimulation on a reference electrode "changed" to a different electrode. They were also assessed on a speech feature discrimination test, a closed-set word recognition test and a nonverbal intelligence task. RESULTS: Sixty-five percent of subjects demonstrated ability to discriminate adjacent electrodes in mid and apical regions of the cochlea, whilst the remaining subjects needed electrode separations of between two and nine electrodes for successful discrimination. In a forward stepwise regression analysis electrode discrimination ability was found to be the strongest factor in accounting for variance in the speech perception scores. Subject variables such as duration of deafness, nonverbal intelligence and implant experience did not significantly account for further variance in the speech perception scores for this group of children. CONCLUSIONS: Electrode discrimination ability was the strongest factor in predicting performance on speech perception measures in a group of children using cochlear implants.

Child↗

PubMed1997

[Cochlear implants in the elderly].

The authors present a retrospective and multicenter study of 18 elderly patients aged above 60 years-old who underwent a cochlear implantation by comparing them with a population of adult patients. The purpose of this study is to evaluate the utility and benefits of cochlear implantation in the elderly by analyzing the clinical data and the results of a questionnaire assessing the use of the implant and the consequences of implantation on the quality of life. The results of this study indicate that the improvement of quality of life in the elderly is similar compared to a control group of adult patients.

Aged↗

PubMed1992

Diameter of the cochlear nerve in deaf humans: implications for cochlear implantation.

Although the parameters that are most important for postoperative speech perception in cochlear implantation have not been identified, it is assumed that the numbers of remaining cochlear neurons and spiral ganglion cells in the implanted deaf ears are critical. In this study, we evaluated the correlation of the maximum diameter of the cochlear and vestibular nerve trunks with the number of spiral ganglion cells in horizontal sections of the temporal bone of 42 patients who were profoundly deaf during life, and in 5 patients with normal hearing. The maximum diameters of the cochlear, vestibular, and eighth cranial nerves were significantly smaller in the deaf population as compared to normal-hearing controls. In addition, the counts of the remaining spiral ganglion cells were significantly correlated with the maximum diameter of the cochlear (p = .0006), vestibular (p = .001), and eighth cranial nerves (p = .0003). The regression equation estimated that 25% of the variance of the spiral ganglion cell count was predicted by the maximum diameter of the eighth nerve. Although the results of this study suggest that preoperative radiographic imaging of the diameter of the eighth nerve may be helpful in predicting the residual spiral ganglion cell count, the wide variability of diameters of the eighth nerve in hearing and deaf subjects militates against this theoretic usefulness.

Adult↗

PubMed2001

[Visualization of cochlear implant electrode movements in the cochlea by using x-ray microscopy].

BACKGROUND: The movements of the electrode cable of a cochlear implant inside the cochlea during the insertion procedure generally are invisible, even in temporal bone experiments. Yet, the development of new designs of electrodes, their positioning near to the modiolus etc. requires an exact knowledge on the dynamic behaviour of the electrodes inside the cochlea. The exclusive method for looking through the undamaged cochlea walls is by x-ray technique. METHODS: A specific x-ray tube with a focal spot size of barely 5 microns allows useful direct magnifications of more than 20-30 times. We performed temporal bone experiments with this tube and studied the behaviour of conventional and perimodiolar electrode cables of a MedEl-Cl during the insertion procedure under fluoroscopic viewing. RESULTS: The high resolution imaging revealed the influence of stiffness of the electrode cable on the insertion depth of a conventional electrode. If the angle of the direction of insertion was too steep, the resulting kinking of the cable at the medial wall of the basal turn was instantly visible. The direct visualisation of the movements of the cable was useful in optimizing the design and stiffness of various prototypes of perimodiolar electrodes for a deep insertion. CONCLUSIONS: The dynamic examination technique disclosed that the stiffness of actual electrode cables is not optimally adapted to the form of the cochlear cavity for deep insertion. The non-destructive visualisation technique will facilitate the development of advanced electrode design, especially for various concepts of perimodiolar electrodes.

Cochlea↗

PubMed2001

Recognition of spectrally asynchronous speech by normal-hearing listeners and Nucleus-22 cochlear implant users.

This experiment examined the effects of spectral resolution and fine spectral structure on recognition of spectrally asynchronous sentences by normal-hearing and cochlear implant listeners. Sentence recognition was measured in six normal-hearing subjects listening to either full-spectrum or noise-band processors and five Nucleus-22 cochlear implant listeners fitted with 4-channel continuous interleaved sampling (CIS) processors. For the full-spectrum processor, the speech signals were divided into either 4 or 16 channels. For the noise-band processor, after band-pass filtering into 4 or 16 channels, the envelope of each channel was extracted and used to modulate noise of the same bandwidth as the analysis band, thus eliminating the fine spectral structure available in the full-spectrum processor. For the 4-channel CIS processor, the amplitude envelopes extracted from four bands were transformed to electric currents by a power function and the resulting electric currents were used to modulate pulse trains delivered to four electrode pairs. For all processors, the output of each channel was time-shifted relative to other channels, varying the channel delay across channels from 0 to 240 ms (in 40-ms steps). Within each delay condition, all channels were desynchronized such that the cross-channel delays between adjacent channels were maximized, thereby avoiding local pockets of channel synchrony. Results show no significant difference between the 4- and 16-channel full-spectrum speech processor for normal-hearing listeners. Recognition scores dropped significantly only when the maximum delay reached 200 ms for the 4-channel processor and 240 ms for the 16-channel processor. When fine spectral structures were removed in the noise-band processor, sentence recognition dropped significantly when the maximum delay was 160 ms for the 16-channel noise-band processor and 40 ms for the 4-channel noise-band processor. There was no significant difference between implant listeners using the 4-channel CIS processor and normal-hearing listeners using the 4-channel noise-band processor. The results imply that when fine spectral structures are not available, as in the implant listener's case, increased spectral resolution is important for overcoming cross-channel asynchrony in speech signals.

Adult↗

PubMed2003

[Acoustic perception in patients using a cochlear implant before and after adjustment sessions].

The aim of the study was comparison of perception of pure tones and speech intelligibility in postlingually deaf patients using a cochlear implant before and after elective adjustment sessions. 10 patients were examined: 5 children (age 8-15.5 years) and 5 adults with cochlear implants NUCLEUS CI22 (6 patients) and NUCLEUS CI24 (4 patients) produced by COCHLEAR (Australia). It was found that between the adjustment sessions all the implanted patients showed deteriorated perception of pure tones throughout all the frequencies and therefore their speech intelligibility worsened. The recommended period between the adjustments is 6 months as acoustic perception degraded with time. However, such observations are not significant in view of insufficient material. Objective assessment of acoustic perception is necessary because subjective sensations are not always true.

Adolescent↗

PubMed2003

[Thermography of the skin covering a cochlear implant--temperature as an indicator for blood circulation].

BACKGROUND: Sufficient blood supply of the flap is a significant factor for proper wound healing and lifelong integration of a cochlear implant. Superficial temperature as an indicator of cutaneous blood circulation can be visualized easily by thermography. QUESTION: We examined the correlation between temperature distribution and the anatomic course of defined arteries, the significance of different types of incisions in this regard, and local irritations of skin temperature/blood circulation by the implant itself. MATERIALS AND METHOD: The partially shaved heads of 15 patients were examined by thermography after cochlear implantation, using the Agema thermovision system. RESULT: Temperature distribution of the skin can be closely related to the arterial blood supply. In our group of patients, no significant alterations could be found in the skin covering the implant. Hair growth in the area tested does not allow valid thermographies. DISCUSSION: By the pattern of temperature-distribution/blood circulation some conclusions about typical incisions can be drawn. While most types of incisions respect the patterns of blood circulation, the retroauricular C-incision may cause problems. Postoperative scars can be regarded as places of minor resistance. CONCLUSIONS: Thermography of the skin is an easy method for estimating the blood circulation of the skin above the implant. It is, however, limited to hair-free or shaved skin areas.

Adolescent↗