Faculty Bibliography

Sensory pathways display heightened plasticity during development, yet the perceptual consequences of early experience are generally assessed in adulthood. This approach does not allow one to identify transient perceptual changes that may be linked to the central plasticity observed in juvenile animals. Here, we determined whether a brief period of bilateral auditory deprivation affects sound perception in developing and adult gerbils. Animals were reared with bilateral earplugs, either from postnatal day 11 (P11) to postnatal day 23 (P23) (a manipulation previously found to disrupt gerbil cortical properties), or from P23-P35. Fifteen days after earplug removal and restoration of normal thresholds, animals were tested on their ability to detect the presence of amplitude modulation (AM), a temporal cue that supports vocal communication. Animals reared with earplugs from P11-P23 displayed elevated AM detection thresholds, compared with age-matched controls. In contrast, an identical period of earplug rearing at a later age (P23-P35) did not impair auditory perception. Although the AM thresholds of earplug-reared juveniles improved during a week of repeated testing, a subset of juveniles continued to display a perceptual deficit. Furthermore, although the perceptual deficits induced by transient earplug rearing had resolved for most animals by adulthood, a subset of adults displayed impaired performance. Control experiments indicated that earplugging did not disrupt the integrity of the auditory periphery. Together, our results suggest that P11-P23 encompasses a critical period during which sensory deprivation disrupts central mechanisms that support auditory perceptual skills. SIGNIFICANCE STATEMENT: Sensory systems are particularly malleable during development. This heightened degree of plasticity is beneficial because it enables the acquisition of complex skills, such as music or language. However, this plasticity comes with a cost: nervous system development displays an increased vulnerability to the sensory environment. Here, we identify a precise developmental window during which mild hearing loss affects the maturation of an auditory perceptual cue that is known to support animal communication, including human speech. Furthermore, animals reared with transient hearing loss display deficits in perceptual learning. Our results suggest that speech and language delays associated with transient or permanent childhood hearing loss may be accounted for, in part, by deficits in central auditory processing mechanisms.

Synapses are highly plastic and are modified by changes in patterns of neural activity or sensory experience. Plasticity of cortical excitatory synapses is thought to be important for learning and memory, leading to alterations in sensory representations and cognitive maps. However, these changes must be coordinated across other synapses within local circuits to preserve neural coding schemes and the organization of excitatory and inhibitory inputs, i.e., excitatory-inhibitory balance. Recent studies indicate that inhibitory synapses are also plastic and are controlled directly by a large number of neuromodulators, particularly during episodes of learning. Many modulators transiently alter excitatory-inhibitory balance by decreasing inhibition, and thus disinhibition has emerged as a major mechanism by which neuromodulation might enable long-term synaptic modifications naturally. This review examines the relationships between neuromodulation and synaptic plasticity, focusing on the induction of long-term changes that collectively enhance cortical excitatory-inhibitory balance for improving perception and behavior.

OBJECTIVE: To assess whether recombinant growth factor (hGH) therapy has an effect on cochlear implant (CI) performance. PATIENTS: Two pediatric CI recipients (S1, S2) who underwent treatment with hGH for short stature were identified for review. S1 has bilateral labyrinthine dysplasia and received implants at ages 10 months (right) and 4 years 3 months (left). S2 was diagnosed with severe to progressive sensorineural hearing loss bilaterally and received a CI at age 9 years 10 months (left). INTERVENTION(S): Case series. MAIN OUTCOME MEASURE(S): Cochlear implant, hGH, and speech perception data were collected. Phonetically Balanced Kindergarten (PBK) and Consonant Nucleus Consonant (CNC) word recognition scores were reviewed to assess auditory perception. Electrode impedances, threshold levels, and comfort levels were also reviewed. RESULTS: After 4 months of hGH, word recognition scores for S1 were observed to decrease from 90 to 72% (right) and were stable at 40% (left). Despite troubleshooting, performance continued to decline bilaterally to 52% (right) and 28% (left), and the decision was made to discontinue hGH. One month after cessation of hGH, word recognition scores began improving to 74% (right) and 68% (left). Word recognition scores for S2 were observed to have decreased from 92% the previous year to 82% after taking hGH for 2 months. Given both our previous experience with S1 and discussions with S2's parents, hGH was discontinued after 10 months of therapy. Two months after cessation of hGH, S2's word recognition had improved to 86% (left). CONCLUSIONS: Our case studies illustrate that implanted children undergoing treatment with hGH may experience a decrease in speech perception, which recovers after the cessation of treatment. Since hGH use has become more prevalent in recent years, it is important to inquire whether children undergoing, or who have undergone, implantation are receiving hGH so that they may be appropriately monitored.

OBJECTIVE: To introduce the otolaryngology community to the current state of research regarding electronic cigarettes, with special attention paid to mechanism, impact on health and addiction, and use in smoking cessation. DATA SOURCES: Review of Google Scholar and PubMed databases using the keywords electronic cigarettes, e-cigs, e-cigarettes, and vaping. In addition, information from media sources as well as news outlets was evaluated to gauge public perception of research findings. REVIEW METHODS: Recent research and randomized controlled trials were prioritized. CONCLUSIONS: The landscape of electronic cigarette devices is evolving, as is the research regarding their risks and benefits. Utilization is rapidly increasing. It appears that older users employ them as a smoking cessation tool compared to younger users. The data are generally inconclusive regarding the benefits of electronic cigarettes for smoking cessation compared with other methods. Furthermore, the safety profile of electronic cigarettes is dynamic and difficult to fully ascertain. IMPLICATIONS FOR PRACTICE: Patients with a variety of otolaryngologic conditions, including cancer, may benefit from frank discussion regarding electronic cigarettes. Furthermore, increasing patient inquiries regarding these devices are likely given their increasing popularity.

The mechanisms underlying perceptual adaptation to severely spectrally-distorted speech were studied by training participants to comprehend spectrally-rotated speech, which is obtained by inverting the speech spectrum. Spectral-rotation produces severe distortion confined to the spectral domain while preserving temporal trajectories. During five 1-hour training sessions, pairs of participants attempted to extract spoken messages from the spectrally-rotated speech of their training partner. Data on training-induced changes in comprehension of spectrally-rotated sentences and identification/discrimination of spectrally-rotated phonemes were used to evaluate the plausibility of three different classes of underlying perceptual mechanisms: (1) phonemic remapping (the formation of new phonemic categories that specifically incorporate spectrally-rotated acoustic information); (2) experience-dependent generation of a perceptual "inverse-transform" that compensates for spectral-rotation; and (3) changes in cue weighting (the identification of sets of acoustic cues least affected by spectral-rotation, followed by a rapid shift in perceptual emphasis to favour those cues, combined with the recruitment of the same type of "perceptual filling-in" mechanisms used to disambiguate speech-in-noise). Results exclusively support the third mechanism, which is the only one predicting that learning would specifically target temporally-dynamic cues that were transmitting phonetic information most stably in spite of spectral-distortion. No support was found for phonemic remapping or for inverse-transform generation.

BACKGROUND: Recent advances in research on thyroid carcinogenesis have yielded applications of diagnostic molecular biomarkers and profiling panels in the management of thyroid nodules. The specific utility of these novel, clinically available molecular tests is becoming widely appreciated, especially in perioperative decision making by the surgeon regarding the need for surgery and the extent of initial resection. METHODS: A task force was convened by the Surgical Affairs Committee of the American Thyroid Association and was charged with writing this article. RESULTS/CONCLUSIONS: This review covers the clinical scenarios by cytologic category for which the thyroid surgeon may find molecular profiling results useful, particularly for cases with indeterminate fine-needle aspiration cytology. Distinct strengths of each ancillary test are highlighted to convey the current status of this evolving field, which has already demonstrated the potential to streamline decision making and reduce unnecessary surgery, with the accompanying benefits. However, the performance of any diagnostic test, that is, its positive predictive value and negative predictive value, are exquisitely influenced by the prevalence of cancer in that cytologic category, which is known to vary widely at different medical centers. Thus, it is crucial for the clinician to know the prevalence of malignancy within each indeterminate cytologic category, at one's own institution. Without this information, the performance of the diagnostic tests discussed below may vary substantially.

OBJECTIVE:To determine the accuracy of pretreatment, contrast-enhanced computed tomography (CT) in the diagnosis of extracapsular spread (ECS) in cervical lymph node metastases from p16-positive head-and-neck squamous cell carcinoma (HNSCC). STUDY DESIGN/METHODS:Retrospective observational study. METHODS:Sixty-five (n = 65) patients diagnosed between 2004 and 2013 with p16-positive HNSCC and with cervical lymph node metastases measuring at least 1 centimeter in diameter on pathological assessment were included. All patients underwent primary surgical treatment. Subjects' preoperative contrast-enhanced neck CT scans were independently assigned a score for the likelihood of ECS (5-point scale) by two board-certified neuroradiologists. Receiver-operating characteristic curves were generated, and optimal sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated for each radiologist. RESULTS:On histological analysis, the majority of patients (58%; 38/65) were found to have ECS, and 29% (19/65) of patients had ≥ three metastatic lymph nodes. For radiologist 1, PPV and NPV for ECS detection were 72% (95% confidence interval (CI), 53%-87%) and 53% (95% CI, 36%-70%), respectively. For radiologist 2, PPV and NPV for ECS detection were 82% (95% CI, 60 %-95%) and 53% (95% CI, 38%-69%), respectively. CONCLUSION/CONCLUSIONS:CT is not a reliable method for determining the presence of ECS in p16-positive HNSCC patients.