Spectral Grouping of Electrically Encoded Sound Predicts Speech-in-Noise Performance in Cochlear Implantees.

OBJECTIVES: Cochlear implant (CI) users exhibit large variability in understanding speech in noise. Past work in CI users found that spectral and temporal resolution correlates with speech-in-noise ability, but a large portion of variance remains unexplained. Recent work on normal-hearing listeners showed that the ability to group temporally and spectrally coherent tones in a complex auditory scene predicts speech-in-noise ability independently of the audiogram, highlighting a central mechanism for auditory scene analysis that contributes to speech-in-noise. The current study examined whether the auditory grouping ability also contributes to speech-in-noise understanding in CI users. DESIGN: Forty-seven post-lingually deafened CI users were tested with psychophysical measures of spectral and temporal resolution, a stochastic figure-ground task that depends on the detection of a figure by grouping multiple fixed frequency elements against a random background, and a sentence-in-noise measure. Multiple linear regression was used to predict sentence-in-noise performance from the other tasks. RESULTS: No co-linearity was found between any predictor variables. All three predictors (spectral and temporal resolution plus the figure-ground task) exhibited significant contribution in the multiple linear regression model, indicating that the auditory grouping ability in a complex auditory scene explains a further proportion of variance in CI users' speech-in-noise performance that was not explained by spectral and temporal resolution. CONCLUSION: Measures of cross-frequency grouping reflect an auditory cognitive mechanism that determines speech-in-noise understanding independently of cochlear function. Such measures are easily implemented clinically as predictors of CI success and suggest potential strategies for rehabilitation based on training with non-speech stimuli.

Comparison of Spontaneous Temporal Bone Cerebrospinal Fluid Leaks From the Middle and Posterior Fossa.

OBJECTIVES: To compare patients surgically managed for spontaneous cerebrospinal fluid (CSF) leaks of the temporal bone arising from the middle cranial fossa (MCF) and posterior cranial fossa (PCF) and to describe the surgical management of posterior fossa CSF leaks. STUDY DESIGN: Retrospective case review. SETTING: Academic tertiary center. PATIENTS: Adult patients presenting with spontaneous temporal bone CSF leaks undergoing operative repair between January 2010 and August 2018. Patients with a history of trauma, previous mastoid surgery, and iatrogenic CSF leaks were excluded. INTERVENTION: Transmastoid or MCF CSF leak repair. MAIN OUTCOME MEASURES: Patient demographics, body mass index (BMI), comorbidities, presenting features, and lumbar puncture opening pressures were compared between groups and the management of the PCF CSF leaks described. RESULTS: Forty-six patients (26 women, 20 men) were included. The mean age at the time of repair was 58.0 ±â€Š12.9 years (±SD). The origin of the CSF leak was from the PCF in three patients and MCF in 43 patients. All three patients with PCF leaks presented with an acute history of meningitis compared with only seven (16%) in the MCF group. This difference was statistically significant (p = 0.01, Fisher's exact test). There were no statistically significant differences in age, sex, BMI, or lumbar puncture opening pressures. The PCF leaks were repaired using a transmastoid approach with multilayer closure of the bony defect and fat graft obliteration of the mastoid. CONCLUSIONS: Spontaneous CSF leaks arising from the PCF are rare and may present more commonly with meningitis. Identification requires careful review of imaging.