Faculty Bibliography

All hearing aids and communication devices introduce nonlinear distortion. The perception of distortion by hearing-impaired subjects was studied using artificial controlled distortions of various amounts and types. Subjects were asked to rate the perceived quality of distorted speech and music. Stimuli were subjected to frequency-dependent amplification as prescribed by the 'Cambridge formula' before presentation via Sennheiser HD580 earphones. The pattern of the ratings was reasonably consistent across subjects, but two of the eight subjects showed inconsistent results for the speech stimuli. Center clipping and soft clipping had only small effects on the ratings, while hard clipping and 'full-range' distortion had large effects. The results indicate that most hearing-impaired subjects are able to make orderly and consistent ratings of degradations in sound quality introduced by nonlinear distortion. The pattern of results could be predicted reasonably well using a model developed to account for the perception of distortion by normally hearing subjects

CONTEXT: Although commonly performed, data are lacking regarding efficacy and safety of lymph node dissection (LND) for recurrent/persistent papillary thyroid cancer (PTC). OBJECTIVE: Evaluate the efficacy and morbidity of LND in recurrent/persistent PTC. DESIGN: Retrospective review of central or lateral LND performed for persistent/recurrent PTC between January 2004 and March 2006. SETTING: Multidisciplinary thyroid cancer clinic with a single surgeon at an academic medical center. PARTICIPANTS: Seventy-five patients who underwent 79 LND for persistent/residual PTC. Safety analysis included all 79 resections. Exclusion criteria for the efficacy analysis were factors prohibiting evaluation of thyroglobulin (Tg) response. Forty-one resections were included in the efficacy analysis. INTERVENTION: Selective LND per standard of care. MAIN OUTCOME MEASURE: Primary outcome was the Tg response to LND. Secondary outcomes were surgical complications. RESULTS: Thirty-nine of the 41 evaluable resections also had Tg data allowing classification of Tg response. Of 39 classifiable resections, 16 (41%) resulted in undetectable postoperative stimulated Tg levels. An additional 12 resections resulted in significant (> or =50%) reductions in suppressed or stimulated Tg levels for an overall improvement rate of 72%. Of all 79 resections, 25 (32%) resulted in minor and 7 (9%) resulted in major complications. CONCLUSIONS: LND for persistent/recurrent PTC is a relatively safe procedure in experienced hands. It can lead to an undetectable Tg in 41% of cases and produce a major Tg reduction in an additional 31%. Its efficacy in short-term follow-up is comparable with that reported for I-131, and it should be considered in the management of persistent/recurrent PTC.

Neural activity in the frontal eye fields controls smooth pursuit eye movements, but the relationship between single neuron responses, cortical population responses, and eye movements is not well understood. We describe an approach to dynamically link trial-to-trial fluctuations in neural responses to parallel variations in pursuit and demonstrate that individual neurons predict eye velocity fluctuations at particular moments during the course of behavior, while the population of neurons collectively tiles the entire duration of the movement. The analysis also reveals the strength of correlations in the eye movement predictions derived from pairs of simultaneously recorded neurons and suggests a simple model of cortical processing. These findings constrain the primate cortical code for movement, suggesting that either a few neurons are sufficient to drive pursuit at any given time or that many neurons operate collectively at each moment with remarkably little variation added to motor command signals downstream from the cortex.

Neuroimaging studies of speech processing increasingly rely on artificial speech-like sounds whose perceptual status as speech or non-speech is assigned by simple subjective judgments; brain activation patterns are interpreted according to these status assignments. The naive perceptual status of one such stimulus, spectrally-rotated speech (not consciously perceived as speech by naive subjects), was evaluated in discrimination and forced identification experiments. Discrimination of variation in spectrally-rotated syllables in one group of naive subjects was strongly related to the pattern of similarities in phonological identification of the same stimuli provided by a second, independent group of naive subjects, suggesting either that (1) naive rotated syllable perception involves phonetic-like processing, or (2) that perception is solely based on physical acoustic similarity, and similar sounds are provided with similar phonetic identities. Analysis of acoustic (Euclidean distances of center frequency values of formants) and phonetic similarities in the perception of the vowel portions of the rotated syllables revealed that discrimination was significantly and independently influenced by both acoustic and phonological information. We conclude that simple subjective assessments of artificial speech-like sounds can be misleading, as perception of such sounds may initially and unconsciously utilize speech-like, phonological processing.

Objective: To examine speech perception outcomes and determine the impact of length of deafness and time between implants on performance in the sequentially bilateral implanted population. STUDY DESIGN: Retrospective review. SETTING: Tertiary academic referral center. PATIENTS: Forty-three children (age, <18 yr) and 22 adults underwent sequential bilateral implantation with at least 6 months between surgeries. The mean age at the time of the second implant in children was 7.83 years, and mean time between implants was 5.16 years. Five children received the first side implant (C1) below 12 months of age; 16, at 12 to 23 months; 9, between the ages of 24 and 35 months; and 11, at 36 to 59 months; 2 were implanted above the age of 5 years. In adults, mean age at second implant was 46.6 years, and mean time between implants was 5.6 years. INTERVENTION: Sequential implantation with 6 months or more between implantations. MAIN OUTCOME MEASURES: Speech perception tests were performed preoperatively before the second implantation and at 3 months postoperatively. RESULTS: Results revealed significant improvement in the second implanted ear and in the bilateral condition, despite time between implantations or length of deafness; however, age of first-side implantation was a contributing factor to second ear outcome in the pediatric population. CONCLUSION: Sequential bilateral implantation leads to significantly better speech understanding. On average, patients improved, despite length of deafness, time between implants, or age at implantation

In this study, we investigated the role of the peripheral endothelin-1 (ET-1) concentration in a cancer pain model. To test the hypothesis that the concentration of ET-1 in the tumor microenvironment is important in determining the level of cancer pain we used two cancer pain mouse models that differed significantly in production of ET-1. The two mouse cancer models were produced by injection of cells derived from a human oral squamous cell carcinoma (SCC) and melanoma into the hind paw of female mice. Pain, as indicated by reduction in withdrawal thresholds in response to mechanical stimulation, was significantly greater in the SCC group than the melanoma group. The peripheral concentration of ET-1 within the cancer microenvironment was significantly greater in the SCC group. Intra-tumor expression of both ET-1 mRNA and ET-1 protein were significantly higher in the SCC model compared to the melanoma model. ET receptor antagonism was effective as an analgesic for cancer pain in the SCC model only. To address the potential confounding factor of tumor volume we evaluated the contribution of tumor volume to cancer pain in the two models. The mean volumes of the tumors in the melanoma group were significantly greater than the tumors in the SCC group. In both groups, the pain level correlated with tumor volume, but the correlation was stronger in the melanoma group. We conclude that ET-1 concentration is a determinant of the level of pain in a cancer pain mouse model and it is a more important factor than tumor volume in producing cancer pain. These results suggest that future treatment regimens for cancer pain directed at ET-1 receptor antagonism show promise and may be tumor type specific

The retrosigmoid technique has evolved from the traditional suboccipital operation and, when combined with removal of the posterior wall of the internal auditory canal (IAC), affords a wide exposure of the cerebellopontine angle. This approach may be used for acoustic neuromas of all sizes, from intracanalicular, to more than 4 cm from the porus acusticus. Hearing preservation may be attempted and is generally successful in a substantial minority of cases. The facial nerve is readily visualized at the lateral end of the IAC and is at no greater risk than in the translabyrinthine operation. The authors use this approach for all hearing preservation surgery as well as for tumors of more than 3 cm, regardless of hearing

Tumors of the cerebellopontine angle (CPA) are common and represent up to 10% of all intracranial tumors. Rarely, intrinsic brainstem tumors can involve the CPA and present with auditory symptoms typical of CPA tumors such as hearing loss, vertigo and tinnitus. We report on a rare case of an intrinsic brainstem neoplasm presenting with steroid responsive fluctuating sensorineural hearing loss in a child. The patient initially presented with an acute worsening of an unilateral sensorineural hearing loss, without additional symptoms, that responded to oral steroids. Otoacoustic emission testing demonstrated normal outer hair cell function suggesting retrocochlear pathology. Magnetic resonance imaging with contrast enhancement revealed an intrinsic neoplasm of the middle cerebellar peduncle impinging on the 7th/8th neurovascular bundle within the CPA. The patient underwent gross total resection of the juvenile pilocytic astrocytoma via retrosigmoid craniotomy and remains disease free at 2 years postoperatively. This case highlights that suspicion of central nervous system pathology should be heightened in the presence of steroid responsive, fluctuating sensorineural hearing loss with normal outer hair cell function

OBJECTIVES: To provide comprehensive temporal trend analysis of 5-year relative survival rates of laryngeal cancer using the Surveillance, Epidemiology, and End Results database; and to expand on prior reports by including inclusion of laryngeal tumor location, stage, age at diagnosis, treatment strategy, and histologic grade. DESIGN: Retrospective cohort analysis using the Surveillance, Epidemiology, and End Results database of the National Cancer Institute. The Surveillance, Epidemiology, and End Results data were used to design 5 cohorts of patients with laryngeal cancer: 1977-1978, 1983-1984, 1989-1990, 1995-1996, and 2001-2002. Five-year survival rates were analyzed according to tumor site, stage, and grade; age at diagnosis; and treatment strategy. The joinpoint regression model was used to assess survival trends and their statistical significance. RESULTS: Among patients with supraglottic cancer, 5-year relative survival rates for distant disease worsened over time while rates for local and regional disease did not change (P = .01 and P > .05, respectively). For localized glottic cancer, survival remained stable from 1977-1978 to 2001-2002. However, patients with regional and distant glottic cancer demonstrated a significant decrease in survival in the past 3 decades (P < .001). This trend was independent of treatment strategy. Finally, the proportion of well-differentiated tumors in patients with regional laryngeal cancer decreased over time (P < .001 for supraglottic and P = .007 for glottic). CONCLUSIONS: A decreasing 5-year survival trend was found among patients with glottic cancer who had regional disease and in all patients with distant disease. Histopathologic trends not previously reported in those with laryngeal cancer seem to parallel those seen in other tobacco-related cancers. These trends may reflect the effect of birth cohorts and implicate the relationship between carcinogenic exposure and host factors, rather than the influence of treatment