Role of slow temporal modulations in speech identification for cochlear implant users.

OBJECTIVE: This study aimed to assess whether the capacity of cochlear implant (CI) users to identify speech is determined by their capacity to perceive slow (< 20 Hz) temporal modulations. DESIGN: This was achieved by studying the correlation between (1) phoneme identification in quiet and in a steady-state or fluctuating (8 Hz) noises, and (2) amplitude-modulation detection thresholds (MDTs) at 8 Hz (i.e. slow temporal modulations). STUDY SAMPLE: Twenty-one CI users, unilaterally implanted with the same device, were tested in free field with their everyday clinical processor. RESULTS: Extensive variability across subjects was observed for both phoneme identification and MDTs. Vowel and consonant identification scores in quiet were significantly correlated with MDTs at 8 Hz (r = - 0.47 for consonants, r = - 0.44 for vowels; p < 0.05). When the masker was a steady-state noise, only consonant identification scores tended to correlate with MDTs at 8 Hz (r = - 0.4; p = 0.07). When the masker was a fluctuating noise, consonant and vowel identification scores were not significantly correlated with MDTs at 8 Hz. CONCLUSIONS: Sensitivity to slow amplitude modulations is correlated with vowel and consonant perception in CI users. However, reduced sensitivity to slow modulations does not entirely explain the limited capacity of CI recipients to understand speech in noise.

Pitch-raising surgery in fourteen male-to-female transsexuals.

OBJECTIVE: To evaluate the indications and results of pitch-raising surgery in male-to-female transsexual patients. STUDY DESIGN: Retrospective study of male-to-female transsexual patients who underwent pitch-raising surgery between 1994 and 2001 at a single institution. METHODS: The 14 patients had inadequate improvements after speech therapy alone. After anterior commissure advancement (n = 2), cricothyroid approximation (n = 9), or both (n = 3), results were evaluated subjectively by the patients and speech therapists and objectively by electroglottographic measurement of fundamental frequencies (usual, maximal, and minimal), postoperative gain in usual fundamental frequency, and the percentage of irregularities. RESULTS: Cricothyropexy disruption occurred in two patients. Median follow-up was 6.5 months. Subjective success rates were 78.5% and 71.5% according to the patients and speech therapists, respectively. Usual, maximal, and minimal frequencies increased significantly; median postoperative gain in usual fundamental frequency was 11 Hz. Three of the four patients with a poor objective result continued to smoke after surgery. CONCLUSION: Pitch-raising surgery induces subjective and objective improvements but should be reserved for patients in whom speech therapy is not sufficiently effective.

Endoscopic rehabilitation of vocal cord paralysis with a silicone elastomer suspension implant.

OBJECTIVES: Because of the side effects of Teflon, the risk of infection from the use of collagen, autologous fat resorption, and the lack of alternative substances, injection laryngoplasty tends to be replaced by laryngeal framework surgery as the method of choice for the treatment of unilateral vocal cord recurrent paralysis (LP). The aim of this study was to evaluate the results, for morbidity and voice quality, of treating this paralysis by injection of a silicone suspension elastomer implant (SSEI). STUDY DESIGN: The study was retrospective, and 19 patients were included. Average follow-up was 25 months (range: 8.3-43). METHODS: Each patient underwent clinical and videostroboscopic assessment, and had an electroglottographic recording. Subjective assessment was obtained by self-evaluation. Results were classified as good, fair, or poor, and were based on 2 objective and 3 subjective criteria. A search was made for biologic signs of autoimmune disorders. RESULTS: Good, fair, and poor results were respectively 79%, 16%, and 5%. Each set of subjective data showed voice improvement (P < 0.05). The fundamental frequency range, percentage of irregularity, and aspiration decreased significantly (P < 0.05). There was only one case of postoperative dyspnea, which resolved after steroid injection. No biologic signs of autoimmune disorders were found. CONCLUSIONS: The use of SSEI is safe. Injection laryngoplasty is easy to perform and avoids cervical scarring. Its results are comparable to those obtained with other techniques, including laryngeal framework surgery, even if there is no standard criterion for the evaluation of voice quality. SSEI injection can reasonably be proposed as a surgical treatment for permanent unilateral vocal cord LP.

Long-term results of surgical treatment of vocal fold nodules.

OBJECTIVES/HYPOTHESIS: To evaluate the long-term outcome of patients with vocal fold nodules treated by surgery alone, or by a combination of surgery and voice therapy and to identify factors associated with long-term recurrent dysphonia. STUDY DESIGN: Retrospective study. METHODS: All patients who had undergone surgery for vocal fold nodules in a tertiary care hospital between 1996 and 2006 were contacted. After giving their consent, they were evaluated by videostroboscopic examination of vocal fold nodules and by a subjective questionnaire including the Voice Handicap Index (VHI). RESULTS: Sixty-two out of 90 patients (69%) (60 women, 2 men with a mean age of 33 years) answered the questionnaire at a mean interval of 9.5 years after surgery. Recurrent dysphonia was observed in 19 patients (30%) at a mean interval of 5.2 years after surgery and new benign vocal fold lesions (nodules or Reinke's edema) were observed in 11 patients (18%). Absence of postoperative voice therapy was significantly associated with a higher recurrence rate (P = 0.02) (56% of recurrent dysphonia without voice therapy versus 22% with voice therapy). CONCLUSIONS: Postoperative voice therapy decreases the risk of recurrence. Vocal fold nodules can recur over a period of 5 years, consequently requiring follow-up for at least 5 years in clinical practice and in future prospective studies.

Effects of amplitude compression on first- and second-order modulation detection thresholds in cochlear implant listeners.

The aim of this study was to examine the effects of instantaneous non-linear amplitude mapping on the detection of single-component and multicomponent temporal envelopes. To address this issue, first- and second-order amplitude modulation detection thresholds were measured in four cochlear implant users with the intervention of the compression device of the implant processor. The compression device is set to produce either a strongly or a weakly logarithmic mapping of stimulus amplitude to electrical amplitude. 'First-order' modulation detection thresholds indicate the ability of listeners to detect sinusoidal amplitude modulation (SAM) applied to a white noise carrier; they are measured as a function of the rate of that modulation, fm. 'Second-order' modulation detection thresholds indicate the ability to detect sinusoidal modulation applied to the depth of a sinusoidally amplitude-modulated signal (here, a 16-Hz sinusoidally amplitude-modulated white noise); they are measured as a function of the rate of the modulation applied to the modulation depth (referred to as fm'). In each task, stimuli are transformed by the implant processor and are presented through one electrode at approximately the same level. The results show that, in cochlear implant listeners, both first- and second-order modulation detection thresholds measured at the lower rates (< or =7 Hz) decrease slightly by about 3-6dB when the stronger compression is used. No effect of compression is observed at higher rates. These results suggest that instantaneous logarithmic amplitude mapping has beneficial- but limited-effects on the detection of single-component and multicomponent temporal envelopes. These results are discussed in light of current models of temporal envelope processing.