Clinical evaluation of the xDP output compression strategy for cochlear implants.

Technological advances in the domain of digital signal processing adapted to cochlear implants (CI) are partially responsible for the ever-improving outcomes observed with this neural prosthesis. The goal of the present study was to evaluate audiometric outcomes with a new signal processing strategy implemented in Oticon Medical-Neurelec cochlear implant systems, the xDP strategy. The core of this approach is a preset-based back-end output compression system, modulating a multi-channel transfer function depending on the intensity and information content of input sounds. Twenty adult CI patients, matched for age and CI experience, were included in this study. Pure-tone thresholds and vocal audiometry scores were measured with their former signal processing strategy and with xDP. Speech perception was assessed using dissyllabic words presented in quiet, at different intensity levels: 40, 55, 70, and 85 dB SPL, and in a cocktail party noise at a signal-to-noise ratio of +10 dB. Results with the xDP strategy showed, as awaited, no major modification of pure-tone thresholds. A global increase of speech perception scores was observed after a 1-month habituation period, with significant improvements for speech perception in quiet for moderate (55 dB SPL), loud speech sounds (85 dB SPL), and speech-in-noise comprehension. Subjective signal quality assessment showed a preference for Crystalis(xDP) over the former strategy. These results allow the quantification of improvements provided by the xDP signal processing strategy.

The Voice Track multiband single-channel modified Wiener-filter noise reduction system for cochlear implants: patients' outcomes and subjective appraisal.

OBJECTIVE: The aim of this study was to evaluate the potential improvements of speech perception and sound quality provided by a multiband single channel noise-reduction algorithm based on the modified Wiener-filter adapted to cochlear implant sound processing. DESIGN: This study was a longitudinal trial with a repeated-measures design. Outcome measures were performed on the first day when the noise reduction feature was provided and after a one month habituation period. Objective measures included pure-tone thresholds and vocal audiometry assessments. Speech perception was measured in quiet and in the presence of two types of noise: a stationary speech shaped noise and a two-talker cocktail noise. Subjective sound quality was assessed using a ten item questionnaire. STUDY SAMPLE: Thirteen post-lingual deaf adults, experienced users of a cochlear implant system, took part in this study. RESULTS: The noise-reduction algorithm provided a benefit for the perception of speech presented in a stationary speech shaped noise and an overall improvement in subjective sound quality ratings. CONCLUSIONS: It was shown that a single channel noise reduction system based on a modified Wiener-filter approach can improve speech in noise perception performance and subjective sound quality in cochlear implant patients.

Speech performance and sound localization abilities in Neurelec Digisonic® SP binaural cochlear implant users.

In this prospective study the outcome of the Digisonic® SP Binaural cochlear implant (CI), a device enabling electric stimulation of both cochleae by a single receiver, was evaluated in 14 postlingually deafened adults after 12 months of use. Speech perception was tested using French disyllabic words in quiet and in speech-shaped noise at +10 dB signal-to-noise ratio. Horizontal sound localization in quiet was tested using pink noise coming from 5 loudspeakers, from -90 to +90° along the azimuth. Speech scores in quiet were 76% (±19.5 SD) in the bilateral condition, 62% (±24 SD) for the better ear alone and 43.5% (±27 SD) for the poorer ear alone. Speech scores in noise were 60% (±27.5 SD), 46% (±28 SD) and 28% (±25 SD), respectively, in the same conditions. Statistical analysis showed a significant advantage of the bilateral use in quiet and in noise (p < 0.05 compared to the better ear). Significant spatial perception benefits such as summation effect (p < 0.05), head shadow effect (p < 0.0001) and squelch effect (p < 0.0005) were noted. Sound localization accuracy improved significantly when using the device in the bilateral condition with an average root mean square of 35°. Compared with published outcomes of usual bilateral cochlear implantation, this device could be a valuable alternative to two CIs. Prospective controlled trials, comparing the Digisonic SP Binaural CI with a standard bilateral cochlear implantation are mandatory to evaluate their respective advantages and cost-effectiveness.

Clinical study on the efficacy, acceptance, and safety of hearing aids in patients with mild to moderate presbyacusis.

BACKGROUND: The primary objective of this trial was to demonstrate the effect of wearing a Hearing aid (HA) on improvement of hearing and comprehension in everyday life situations. METHODS: This single-center phase IV open-label clinical trial was carried out on men or women 40 years old or more, presenting mild or moderate first-degree presbyacusis. Presbyacusis was diagnosed by performance of pure-tone audiometry in silence. The main criterion was the comparison of the Glasgow Hearing Aid Benefit Profile (GHABP) before wearing HA and after a month of use and the secondary one was audiometric parameters. RESULTS: Forty-seven patients (mean age 60.0±6.9 years) were included in the study. After 4 weeks, when wearing HA, no significant difficulty remains in the patients when they watch television (GHABP situation 1) or when they have a conversation without background noise (GHABP situation 2). To have a conversation in a busy street or a shop GHABP (situation 3) 4.4% of patients still have great difficulty, as are 2.2% of them when participating in a group conversation (GHABP situation 4). The GHABP score of residual disability for the whole of the 4 situations of difficulty is 1.3±0.5, translating into no or only slight residual disability, in very significant amelioration of 1.3±0.7 points (P<0.0001), or 46.4% compared to the initial value. Audiometric parameters were also significantly improved. CONCLUSIONS: This study has allowed us to highlight from a clinical as well as an audiometric perspective the safety, effectiveness, as well as the important benefit of Sonalto® pre-set hearing aids on the improvement of hearing in patients presenting incipient presbyacusis.

The relationship between electrical auditory brainstem responses and perceptual thresholds in Digisonic® SP cochlear implant users.

Determining the electrical stimulation levels is often a difficult and time-consuming task because they are normally determined behaviorally - a particular challenge when dealing with pediatric patients. The evoked stapedius reflex threshold and the evoked compound action potential have already been shown to provide reasonable estimates of the C- and T-levels, although these estimates tend to overestimate the C- and T-levels. The aim of this study was to investigate whether the evoked auditory brainstem response (eABR) can also be used to reliably estimate a patient's C- and T-levels. The correlation between eABR detection thresholds and behaviorally measured perceptual thresholds was statistically significant (r = 0.71; P < 0.001). In addition, eABR Wave-V amplitude increased with increasing stimulation level for the three loudness levels tested. These results show that the eABR detection threshold can be used to estimate a patient's T-levels. In addition, Wave-V amplitude could provide a method for estimating C-levels in the future. The eABR objective measure may provide a useful cochlear implant fitting method - particularly for pediatric patients.

Pulsatile tinnitus cured by mastoidectomy.

Tinnitus of venous origin is a rare occurrence. It represents roughly half of cases of vascular tinnitus. The choice of treatment is not easy, even when the diagnosis is certain. Reassurance of the patient is often sufficient. Nevertheless, a surgical treatment is sometimes performed--usually ligature of the internal jugular vein. We present the case of a patient with a right venous pulsatile tinnitus and a history of 5 years of ineffective medical and surgical treatments. Ligature of the internal jugular vein was not chosen in this case: a computed tomographic scan showed filled mastoid cells, and mastoidectomy was performed instead. The tinnitus disappeared immediately after surgery and has not recurred during a 2-year follow-up. The bilateral preoperative sensorineural and conductive hearing loss also disappeared. Pulsatile tinnitus of venous origin is usually treated with ligature of the internal jugular vein. Mastoidectomy is an interesting alternative in selected cases.

Phase 2 study of intratumoral cisplatin and epinephrine treatment for locally recurrent head and neck tumors.

Local relapses of head and neck tumors are not often eligible for surgical and/or radiotherapy retreatment, and the efficacy of systemic chemotherapy is poor. A greater accumulation and efficacy of anticancer drugs with lower systemic toxicity is theoretically obtained with intratumoral chemotherapy. In experimental studies, epinephrine has been shown to increase the concentration and antitumor effect of intratumoral cisplatin. Fourteen patients with locally recurrent head and neck tumors (median age, 58.7 years) were included in this phase 2 trial. Recurrent tumors (squamous cell carcinomas) were located on the tongue, oral pharynx, or cervical nodes. Prior therapy was surgery and/or radiotherapy with or without intravenous chemotherapy. Inclusion criteria included an Eastern Cooperative Oncology Group/World Health Organization performance status of 0, 1, or 2, an anticipated survival of >3 months, adequate cardiac, kidney, liver, and bone marrow function, and no coagulopathy or carotid invasion. Fifty intratumoral injections of cisplatin-epinephrine (average, 3.6 injections per patient; range, 1 to 5 injections) were given to the 14 patients from November 1998 to July 2000. Patients were treated with cisplatin (1 mg/mL; maximum dose, 50 mg) at an injection volume corresponding to the tumor volume (1 mL/cm3 of tumor; maximum volume, 50 mL). Epinephrine was added at a concentration of 0.02 mg/mL. Intratumoral injections were repeated every 2 to 3 weeks at different locations in the tumors to obtain a homogeneous distribution. Tumor response was evaluated by clinical examination and computed tomography. Eight objective responses were registered among the 14 patients. Four were complete responses, and 4 were partial responses. The average time to disease progression was 11.5 +/- 8.9 weeks. Local adverse effects were transient pain, swelling, and erythema at the site of the injection. No nephrotoxicity, neurotoxicity, or ototoxicity was observed. Intratumoral injection of cisplatin and epinephrine in an aqueous solution has a definite antitumor activity in recurrent head and neck cancer with acceptable local tolerance and no major systemic toxic effects except for transient tachycardia and high blood pressure at the time of injection.

Traumatic retropharyngeal hematoma: a rare and critical pathology needed for early diagnosis.

Retropharyngeal hematoma occurs rarely. It is located just in front of the cervical spine. Many circumstances can lead to its development. A trauma and/or anticoagulants are often key factors. The assessment must be made extremely carefully as such a hematoma can induce an airway compromise. Trauma being a key factor, it can also present with cervical spine fractures, increasing the risks. Two different cases of retropharyngeal hematomas are reported. The first case required surgical management with tracheotomy, per-oral drainage and naso-gastric tube feeding. A total recovery was obtained in 2 weeks. The second patient underwent medical treatment (methylprednisolone), and recovery was obtained in 6 days. Surgery for retropharyngeal hematoma is not always mandatory. It becomes necessary when a major dysphagia or dyspnea occurs. In other cases, medical treatment and close observation are usually sufficient.

EDTA enhances the antitumor efficacy of intratumoral cisplatin in s.c. grafted rat colon tumors.

We have investigated whether EDTA, a calcium chelator, could improve the accumulation of platinum in tumors and enhance the antitumor efficacy by increasing drug diffusion through the extracellular tumor matrix. Intratumoral injection of 0.3 mg/kg cisplatin combined with 10 mg/ml EDTA in 2 ml saline serum led to tumor cure in four of eight rats and produced major tumor regression in the other animals. In contrast, intratumoral injection of cisplatin alone or EDTA alone had no antitumoral effect. EDTA increased platinum accumulation both in vivo and ex vivo in the PROb tumors. EDTA alone was cytotoxic at a concentration of 10 mg/ml, but neither increased platinum accumulation nor cisplatin toxicity on cultured PROb colonic cancer cells. We conclude that EDTA could be a useful and well-tolerated adjuvant for enhancing intratumoral cisplatin chemotherapy.