Yanmei Feng

Tonsillectomy versus Tonsillotomy for Sleep-Disordered Breathing in Children: A Meta Analysis

Objectives Tonsillotomy has gained popular acceptance as an alternative to the traditional tonsillectomy in the management of sleep-disordered breathing in children. Many studies have evaluated the outcomes of the two techniques, but uncertainty remains with regard to the efficacy and complications of tonsillotomy versus a traditional tonsillectomy. This study was designed to investigate the efficacy and complications of tonsillotomy versus tonsillectomy, in terms of the short- and long-term results. Methods We collected data from electronic databases including MEDLINE, EMBASE, and the Cochrane Library. The following inclusion criteria were applied: English language, children, and prospective studies that directly compared tonsillotomy and tonsillectomy in the management of sleep disordered breathing. Subgroup analysis was then performed. Results In total, 10 eligible studies with 1029 participants were included. Tonsillotomy was shown to be advantageous over tonsillectomy in short-term measures, such as a lower hemorrhage rate, shorter operation time, and faster pain relief. In long-term follow-up, there was no significant difference in resolution of upper-airway obstructive symptoms, the quality of life, or postoperative immune function between the tonsillotomy and tonsillectomy groups. The risk ratio of SDB recurrence was 3.33 (95% confidence interval = 1.62 6.82, P = 0.001), favoring tonsillectomy at an average follow-up of 31 months. Conclusions Tonsillotomy may be advantageous over tonsillectomy in the short term measures and there are no significant difference of resolving obstructive symptoms, quality of life and postoperative immune function. For the long run, the dominance of tonsillotomy may be less than tonsillectomy with regard to the rate of sleep-disordered breathing recurrence.

Temporal Resolution in Regions of Normal Hearing and Speech Perception in Noise for Adults with Sloping High-Frequency Hearing Loss

Objectives: (1) To determine whether high-frequency sensorineural hearing loss (HF SNHL) is accompanied by deterioration in temporal resolution in the low-frequency region where hearing sensitivity is within normal range. (2) To evaluate whether such temporal processing deficits contribute to speech perception difficulty in noise. Design: A between-group design was employed, using subjects either with or without high-frequency hearing loss and matched by age. Temporal resolution was evaluated in amplitude modulation (AM) detection and gap detection tasks. To restrict evaluation to the low-frequency regions where the auditory sensitivity was virtually normal, low-pass noise carriers (for AM detection) and gap markers (for gap detection) were used. The impact of temporal processing deficits on speech perception was evaluated using hearing in noise tests (HINT) with varied time compression rates of the speech materials. Results: Adults with high-frequency hearing loss showed poorer performance than the age-matched normal-hearing subjects on both the AM and gap detection tasks, even though the stimuli were restricted to regions of observed normal sensitivity. With increasing time compression, listeners with HF SNHL required a larger signal to noise ratio to maintain accuracy in speech perception in adaptive HINT and exhibited a bigger decrease in score for HINTs at a fixed signal to noise ratio. Multiple regression/correlation analyses show significant correlation across the scores of AM/gap detection tasks and HINTs. Conclusions: Temporal resolution in the low-frequency region with near-normal sensitivity seems to be deteriorated in subjects with HF SNHL. They were more sensitive to increases in speech rate, suggesting that poorer temporal processing may be related to speech perception deficits in noise.

Local inhibition shapes duration tuning in the inferior colliculus of guinea pigs

Neural tuning to sound durations is a useful filter for the identification of a variety of sounds. Previous studies have shown that the interaction between excitatory and inhibitory inputs plays a role in duration selectivity in echolocating bats. However, this has not been investigated in non-echolocating mammals. In the inferior colliculus (IC) of these mammals, it is recognized that the excitatory responses to sounds are mediated through AMPA and NMDA receptors while the inhibitory input is mediated through gamma-aminobutyric acid (GABA) and glycine receptors. The present study explores the potential interplay between inhibitory and excitatory inputs and its role in the duration selectivity of IC neurons in guinea pigs. It was found that the application of bicuculline (BIC, a GABA A blocker) and/or strychnine (STRY, a glycine blocker) eliminated or reduced duration tuning in most units that were duration tuned (32 out of 39 for BIC, 50 out of 64 for STRY, respectively). The inhibitory input (either by GABA or by glycine) appeared to have a stronger regulating effect on the early excitation mediated by AMPA than on later excitation by NMDA. This is more distinguishable in neurons that show duration selectivity. In conclusion, the inhibitory effect on the early responses appears to be the main contributor for the duration selectivity of the IC in guinea pigs; potential mechanisms for this duration selectivity are also discussed.

The effect of noise-induced sloping high-frequency hearing loss on the gap-response in the inferior colliculus and auditory cortex of guinea pigs

Gap detection has been used as an evaluation tool for temporal processing in subjects with sensorineural hearing loss (SNHL). However, the results from other reports are varied making it difficult to clearly define the impact of SNHL on the temporal processing ability of the auditory system. Specifically, we do not know if and how a high-frequency hearing loss impacts, presumably through off-channel interaction, the temporal processing in low-frequency channels where hearing sensitivity is virtually normal. In this experiment, gap-evoked responses in a low-frequency band (0.5-8 kHz) were recorded in the inferior colliculus (IC) and auditory cortex (AC) of guinea pigs through implanted electrodes, before and after a slopping high-frequency hearing loss, which was induced by over-stimulation using a 12-kHz-tone. The results showed that the gap thresholds in the low-frequency region increased gradually and became significantly higher 8 weeks after the induced high-frequency hearing loss. In addition, the response latency was slightly increased in the IC but this was not true for the AC. These results strongly indicate that a high-frequency hearing loss exerted an off-channel impact on temporal processing in the low-frequency region of the auditory system.

Sine-wave speech recognition in a tonal language

It is hypothesized that in sine-wave replicas of natural speech, lexical tone recognition would be severely impaired due to the loss of F0 information, but the linguistic information at the sentence level could be retrieved even with limited tone information. Forty-one native Mandarin-Chinese-speaking listeners participated in the experiments. Results showed that sine-wave tone-recognition performance was on average only 32.7% correct. However, sine-wave sentence-recognition performance was very accurate, approximately 92% correct on average. Therefore the functional load of lexical tones on sentence recognition is limited, and the high-level recognition of sine-wave sentences is likely attributed to the perceptual organization that is influenced by top-down processes.

Comparative study of the efficacy of the canalith repositioning procedure versus the vertigo treatment and rehabilitation chair

Abstract Conclusion: Vertigo treatment and rehabilitation chair (TRV) may be suggested as the first choice for patients with posterior canal benign paroxysmal positional vertigo (p-BPPV). Objective: To investigate the short- and long-term treatment efficacy of the canalith repositioning procedure (CRP) versus TRV for patients with p-BPPV. Methods: A total of 165 patients with unilateral p-BPPV were assigned to either the CRP group or the TRV group. Patients were assessed at 1 week, 4 weeks, 3 months, and 6 months after their first treatment. The numbers of treatment sessions required for successful repositioning in both groups at 4 weeks, 3 months, and 6 months were recorded. Results: Treatment efficacy of patients in the TRV group was significantly better than that of patients in the CRP group 1 week after the first treatment. The number of treatment sessions needed for successful repositioning was significantly lower in the TRV group than in the CRP group at 4 weeks and 3 months after the first treatment.

General anesthesia changes gap-evoked auditory responses in guinea pigs.

Conclusion. General anesthesia induced by sodium pentobarbital reduces temporal resolution as represented by an increase in the threshold of gap-evoked auditory responses in guinea pigs. Objectives. To explore the potential impact of general anesthesia by sodium pentobarbital (PB), a common anesthetic used in animal research, on gap-evoked responses. Materials and methods. The evoked potentials in response to gaps formed by bursts of broadband noise were recorded from electrodes implanted in the inferior colliculus (IC) and the auditory cortex (AC) of guinea pigs. The gap responses were compared in three conditions: unanesthetized and anesthetized with two doses of sodium pentobarbital (40 mg/kg and 20 mg/kg). Results. PB increased the gap response thresholds, especially when applied at the higher dose. The threshold shift induced by PB was greater in the AC than in the IC. In addition, the higher dose of PB significantly increased the gap response latency in both IC and AC, and decreased response amplitude in IC only.

The roles of local inhibition mediated by γ-aminobutyric acid (GABA)-A receptor in duration tuning in the inferior colliculus of guinea pigs

Conclusion. GABA-mediated inhibition is responsible for the duration tuning in the inferior colliculus (IC) of guinea pigs, a non-echo-locating mammal. Duration tuning in this species is better demonstrated in an appropriate short time window. Objectives. To investigate the role of GABA-mediated inhibition in duration tuning of neurons in the IC of guinea pigs. Materials and methods. Duration tuning pattern was recorded by measuring the spikes of single neurons in response to broadband noise of different durations. The effect of GABA-mediated inhibition was verified by comparing the responses with and without the use of the GABA-A receptor blocker bicuculline (BIC), which was applied using micro-iontophoresis. Results. In addition to overall increase in responsiveness, the application of BIC was found to significantly reduce or eliminate the duration selectivity in 44 of the 67 neurons that showed clear duration tuning from a sample of total 340 neurons.

A Pilot Study of EEG Source Analysis Based Repetitive Transcranial Magnetic Stimulation for the Treatment of Tinnitus

Objective Repetitive Transcranial Magnetic Stimulation (rTMS) is a novel therapeutic tool to induce a suppression of tinnitus. However, the optimal target sites are unknown. We aimed to determine whether low-frequency rTMS induced lasting suppression of tinnitus by decreasing neural activity in the cortex, navigated by high-density electroencephalogram (EEG) source analysis, and the utility of EEG for targeting treatment. Methods In this controlled three-armed trial, seven normal hearing patients with tonal tinnitus received a 10-day course of 1-Hz rTMS to the cortex, navigated by high-density EEG source analysis, to the left temporoparietal cortex region, and to the left temporoparietal with sham stimulation. The Tinnitus handicap inventory (THI) and a visual analog scale (VAS) were used to assess tinnitus severity and loudness. Measurements were taken before, and immediately, 2 weeks, and 4 weeks after the end of the interventions. Results Low-frequency rTMS decreased tinnitus significantly after active, but not sham, treatment. Responders in the EEG source analysis-based rTMS group, 71.4% (5/7) patients, experienced a significant reduction in tinnitus loudness, as evidenced by VAS scores. The target site of neuronal generators most consistently associated with a positive response was the frontal lobe in the right hemisphere, sourced using high-density EEG equipment, in the tinnitus patients. After left temporoparietal rTMS stimulation, 42.8% (3/7) patients experienced a decrease in tinnitus loudness. Conclusions Active EEG source analysis based rTMS resulted in significant suppression in tinnitus loudness, showing the superiority of neuronavigation-guided coil positioning in dealing with tinnitus. Non-auditory areas should be considered in the pathophysiology of tinnitus. This knowledge in turn can contribute to investigate the pathophysiology of tinnitus.

Cortical responses to amplitude modulation in guinea pigs and the effects of general anesthesia by pentobarbital

Test of amplitude modulation detection threshold against modulation frequency (Mf) is one of the major measures in behavior studies for exploring temporal acuity of the auditory system. In this experiment, we recorded cortical responses from implanted electrodes in guinea pigs to generate temporal modulation transfer functions (TMTFs) by calculating the response amplitude changes across a range of Mfs in order to evaluate the temporal resolution in different frequency regions. A -3dB cutoff frequency was measured from each TMTFs and was used as a single-value index for temporal resolution. We found that the temporal resolution, as represented by this index, did not change significantly with the carrier frequency. This result suggested that the temporal resolution of the auditory system is not simply determined by the bandwidth of peripheral auditory channels. We further evaluated the effects of the general anesthesia by pentobarbital on temporal acuity and found that, in addition to the suppressions of response amplitude, this anesthesia significantly decreases the -3dB cutoff frequencies of TMTF.