The electrically evoked compound action potential (eCAP) is a routinely performed measure of the auditory nerve in cochlear implant users. Using a convolution model of the eCAP, additional ...information about the neural firing properties can be obtained, which may provide relevant information about the health of the auditory nerve. In this study, guinea pigs with various degrees of nerve degeneration were used to directly relate firing properties to nerve histology. The same convolution model was applied on human eCAPs to examine similarities and ultimately to examine its clinical applicability. For most eCAPs, the estimated nerve firing probability was bimodal and could be parameterised by two Gaussian distributions with an average latency difference of 0.4 ms. The ratio of the scaling factors of the late and early component increased with neural degeneration in the guinea pig. This ratio decreased with stimulation intensity in humans. The latency of the early component decreased with neural degeneration in the guinea pig. Indirectly, this was observed in humans as well, assuming that the cochlear base exhibits more neural degeneration than the apex. Differences between guinea pigs and humans were observed, among other parameters, in the width of the early component: very robust in guinea pig, and dependent on stimulation intensity and cochlear region in humans. We conclude that the deconvolution of the eCAP is a valuable addition to existing analyses, in particular as it reveals two separate firing components in the auditory nerve.
The preservation of residual hearing has become a high priority in cochlear implant surgery. This study was designed to substantiate whether conservation of residual hearing can be preserved after ...cochlear implantation using the suprameatal approach.
Retrospective chart review.
Retrospective chart review was performed in 109 severely to profoundly hearing impaired cochlear recipients who had some measurable hearing preoperatively. Subsequently, the pre- and postoperative pure-tone thresholds were analyzed by three different analyses to observe the degree of hearing preservation.
Single-subject results showed a complete conservation of residual hearing (change in pure-tone average ΔPTA ≤ 10 dB) in 27 of 109 patients (24.7%). Partial conservation of residual hearing (ΔPTA > 10 dB) was observed in 77 patients (70.6%), but these percentages have been affected severely by ceiling effects. Furthermore, group-subject results demonstrated that the median postoperative PTA was 11.7 dB worse than the preoperative PTA. For individual frequencies, the median deteriorations were 15, 20, 10, and 5 dB at 250, 500, 1,000, and 2,000 Hz, respectively. Stratification for the absence of postoperative hearing thresholds showed a conservation of measurable postoperative hearing levels in 17.4% of all study patients.
The results of this study demonstrate that complete preservation of residual hearing is possible in a limited number of patients using the suprameatal approach technique for cochlear implantation. For a reliable analysis of the audiometric effects of cochlear implant surgery, it is important to take into account the ceiling effects, therefore using different calculation methods to estimate the accurate deterioration of hearing thresholds.
To review the postoperative radiographic investigations of patients implanted with a cochlear implant.
Retrospective case series.
Thirty-nine patients (22-77 yrs old) implanted for sensorineural ...deafness in the cochlear implants program of the Academic Medical Center of Amsterdam.
Cochlear implantation with Cochlear Nucleus 24 Contour and Cochlear Nucleus Freedom (Cochlear Corp., Lane Cove, New South Wales, Australia) implant.
This retrospective analysis of the postoperative computed tomographic scans showed that, in a large number of the implantations, the external ball electrode of the cochlear implant migrated from the insertion place toward the magnet of the receiver/stimulator unit of the implant. It seems that this migration of the external ball electrode does not influence the function of the cochlear implant and the result of the hearing rehabilitation in the short term.
Because of the magnetic field of the receiver/stimulator unit of the cochlear implant and the magnet of the external transmitting coil of the speech processor, it seems to be possible that the extracochlear ball electrode can migrate in the space between the temporal bone and the temporal muscle during the postoperative healing phase. The importance of our observation is still not clear.
The Advanced Bionics® (AB)-York crescent of sound is a new test setup that comprises speech intelligibility in noise and localization tests that represent everyday listening situations. One of its ...tests is the Sentence Test with Adaptive Randomized Roving levels (STARR) with sentences and noise both presented from straight ahead. For the Dutch population, we adopted the AB-York setup and replaced the English sentences with a validated set of Dutch sentences. The Dutch version of the STARR is called the Utrecht-STARR (U-STARR). This study primarily assesses the validity and reliability of the U-STARR compared to the Plomp test, which is the current Dutch gold standard for speech-in-noise testing. The outcome of both tests is a speech reception threshold in noise (SRTn). Secondary outcomes are the SRTn measured with sounds from spatially separated sources (SISSS) as well as sound localization capability. We tested 29 normal-hearing adults and 18 postlingually deafened adult patients with unilateral cochlear implants (CI). This study shows that the U-STARR is adequate and reliable and seems better suited for severely hearing-impaired persons than the conventional Plomp test. Further, CI patients have poor spatial listening skills, as demonstrated with the AB-York test.
Objectives/Hypothesis:
The preservation of residual hearing has become a high priority in cochlear implant surgery. This study was designed to substantiate whether conservation of residual hearing ...can be preserved after cochlear implantation using the suprameatal approach.
Study Design:
Retrospective chart review.
Methods:
Retrospective chart review was performed in 109 severely to profoundly hearing impaired cochlear recipients who had some measurable hearing preoperatively. Subsequently, the pre‐ and postoperative pure‐tone thresholds were analyzed by three different analyses to observe the degree of hearing preservation.
Results:
Single‐subject results showed a complete conservation of residual hearing (change in pure‐tone average ΔPTA ≤ 10 dB) in 27 of 109 patients (24.7%). Partial conservation of residual hearing (ΔPTA > 10 dB) was observed in 77 patients (70.6%), but these percentages have been affected severely by ceiling effects. Furthermore, group‐subject results demonstrated that the median postoperative PTA was 11.7 dB worse than the preoperative PTA. For individual frequencies, the median deteriorations were 15, 20, 10, and 5 dB at 250, 500, 1,000, and 2,000 Hz, respectively. Stratification for the absence of postoperative hearing thresholds showed a conservation of measurable postoperative hearing levels in 17.4% of all study patients.
Conclusions:
The results of this study demonstrate that complete preservation of residual hearing is possible in a limited number of patients using the suprameatal approach technique for cochlear implantation. For a reliable analysis of the audiometric effects of cochlear implant surgery, it is important to take into account the ceiling effects, therefore using different calculation methods to estimate the accurate deterioration of hearing thresholds.
In this evidence-based case report, the authors addressed the following clinical question: What is the effect of a mandibular repositioning appliance (MRA) in patients with nonapneic snoring on the ...snoring loudness, partners' sleep disturbance, and quality of life? The authors retrieved relevant publications from Embase, PubMed, Cinahl, CENTRAL, and Web of Science. They used title and abstract field searches with relevant synonyms for the domain, patients with nonapneic snoring, and for the determinant, MRA. The search yielded 499 records. After selection based on relevance and validity, 2 articles remained for answering the authors' clinical question. The authors pooled the data for the level of snoring. MRA as compared to placebo resulted in a reduction of snoring loudness in 38% of patients with nonapneic snoring and in an improvement of sleep disturbance in 54% of the partners. No effect on quality of life and daytime sleepiness of partners was found. Furthermore, evidence for sustained long-term effects and complete recovery is lacking.
The main advantage of using the KTP (potassium-titanyl-phosphate) laser for stapedotomy instead of the conventional micropick instrument is the smaller risk for mechanical damage. However, the KTP ...laser could theoretically inflict damage to inner ear structures. We hypothesize that KTP laser light wavelength (λ) = 532 nm is hardly absorbed in perilymph but well absorbed in solid structures. The aim of this pilot study was to assess if damage occurred after KTP laser cochleostomy in an animal model and, if so, to what extent and at which settings.
In six guinea pigs, a KTP laser cochleostomy at the basal turn was created. Laser settings of 1, 3 and 5 W and 100 ms pulse time (n = 2 each) were used. Histological preparations were studied for damage to neuroendothelial cells and intrascalar blood.
No damage to inner ear neuroendothelial cells was observed, even at the highest power. Blood clots in the scala tympani from vessels in the cochlear wall were seen. The effects were minimal in the lowest, currently clinically used settings.
KTP laser cochleostomy gives no damage to inner ear neuroendothelial cells but may cause intrascalar hemorrhages.
Abstract
Oropharyngeal squamous cell carcinoma (
OPSCC
) is associated with human papillomavirus (
HPV
) in a proportion of tumors.
HPV
‐positive
OPSCC
is considered a distinct molecular entity with ...a prognostic advantage compared to
HPV
‐negative cases. Silencing of cancer‐related genes by
DNA
promoter hypermethylation may play an important role in the development of
OPSCC
. Hence, we examined promoter methylation status in 24 common tumor suppressor genes in a group of 200
OPSCC
s to determine differentially methylated genes in
HPV
‐positive versus
HPV
‐negative primary
OPSCC
. Methylation status was correlated with
HPV
status, clinical features, and patient survival using multivariate methods. Additionally, methylation status of 16 cervical squamous cell carcinomas (
SCC
) was compared with
HPV
‐positive
OPSCC
. Using methylation‐specific probe amplification,
HPV
‐positive
OPSCC
showed a significantly higher cumulative methylation index (
CMI
) compared to
HPV
‐negative
OPSCC
(
P
=0.008). For the genes
CDH
13
,
DAPK
1
, and
RARB
, both
HPV
‐positive and
HPV
‐negative
OPSCC
showed promoter hypermethylation in at least 20% of the tumors.
HPV
status was found to be an independent predictor of promoter hypermethylation of
CADM
1
(
P
< 0.001),
CHFR
(
P
= 0.027), and
TIMP
3
(
P
< 0.001).
CADM
1
and
CHFR
showed similar methylation patterns in
OPSCC
and cervical
SCC
, but
TIMP
3 showed no methylation in cervical
SCC
in contrast to
OPSCC
. Methylation status of neither individual gene nor
CMI
was associated with survival. These results suggest that
HPV
‐positive tumors are to a greater extent driven by promotor hypermethylation in these tumor suppressor genes. Especially
CADM
1
and
TIMP
3
are significantly more frequently hypermethylated in
HPV
‐positive
OPSCC
and
CHFR
in
HPV
‐negative tumors.
Efficacy of the SPEAK and ACE coding strategies was compared with that of a new strategy, MP3000™, by 37 European implant centers including 221 subjects. The SPEAK and ACE strategies are based on ...selection of 8-10 spectral components with the highest levels, while MP3000 is based on the selection of only 4-6 components, with the highest levels relative to an estimate of the spread of masking. The pulse rate per component was fixed. No significant difference was found for the speech scores and for coding preference between the SPEAK/ACE and MP3000 strategies. Battery life was 24% longer for the MP3000 strategy. With MP3000 the best results were found for a selection of six components. In addition, the best results were found for a masking function with a low-frequency slope of 50 dB/Bark and a high-frequency slope of 37 dB/Bark (50/37) as compared to the other combinations examined of 40/30 and 20/15 dB/Bark. The best results found for the steepest slopes do not seem to agree with current estimates of the spread of masking in electrical stimulation. Future research might reveal if performance with respect to SPEAK/ACE can be enhanced by increasing the number of channels in MP3000 beyond 4-6 and it should shed more light on the optimum steepness of the slopes of the masking functions applied in MP3000.
PDF
