Contralateral Stapedial Reflex Research Articles

Prevalence of Chronic Middle Ear Effusion in Cases of Cleft Palate.

Chronic middle ear effusion is generally present in children with cleft palate (CP) associated with or without cleft lips. The aim of our study was to assessment of how common middle ear effusion is in patients with cleft palates and to evaluate the presence of these symptoms by performing a Basic Audiological Evaluation (BAE). A retrospective randomized study was conducted on 50 children (29 male and 21 female) aged 2 to 16 years who had CPs (associated with or without cleft lips) with symptoms of middle ear effusion. The study was conducted from March 2021 to February 2022. Data review included the results of otoscopic findings and BAE. The Fundamentals of BAE comprise the testing of middle ear function with tympanometry and a pure tone audiometry to determine the kind and degree of hearing impairment. Regarding the BAE, we found that 70% of the children with normal hearing, 24% with conductive type of hearing loss, and 6% with mixed type of hearing loss. The tympanometric results revealed that 66% of the children with type A tympanogram, 24% with type C tympanogram, and 10% with type B tympanogram. The contralateral stapedial reflex was present in 60% of the patients while in 40% of cases not present. The results confirmed the great prevalence of chronic middle ear effusion in children with CPs. Furthermore, the hearing impairment associated with middle ear effusion was visible, demonstrating that middle ear effusion was linked with the prevalence of moderate conductive type of hearing loss. The OME in cases of CP necessitates early prediction and in turn early treatment.

Children With Phenylketonuria Treated Early

Individuals with phenylketonuria (PKU) can exhibit deficits in executive functions, intelligence, attention, visual-spatial processing abilities, and efficiency stemming presumably from deficient neurotransmitter synthesis, even when the disorder is diagnosed and treated early. Basic audiological and electrophysiological evaluations were used to examine the peripheral and central auditory pathways of children with early-treated PKU, who followed adequate versus inadequate diets. Results were compared with those of age-matched children without PKU. The control group included 35 children aged 5 to 16 years, and the experimental group included 25 children with classic PKU, all of whom were diagnosed and treated early. The experimental group comprised children of two subgroups, divided according to their dietary control, as follows: 8 children aged 6 to 13 years with adequate diets (group A); 17 children ages 6 to 15 years demonstrating inadequate diets (group B). All participants underwent auditory evaluations, including otoscopy, pure-tone and speech audiometry, immittance testing (tympanometry and assessment of contralateral stapedial reflex thresholds), and evaluations of auditory brainstem and middle latency responses. The demographic variables and audiological examination results were analyzed for all groups. Results among groups and subgroups were compared using analysis of variance with repeated measures to test statistical significance across factors and measures at the p = 0.05 level. Audiometric evaluation revealed results within normal limits for all groups, except for one child from the inadequate diet group, who showed a mild bilateral conductive hearing loss. Results of speech and immittance audiometry suggested the children in group B as having poorer average speech-discrimination scores and higher stapedial reflex thresholds at 4000 Hz. Auditory brainstem response results revealed longer average latencies for waves III and V and greater interaural differences for wave V in group B, although both groups A and B showed longer average latencies for the interpeak interval I-V, compared with the control group. Middle latency responses showed no significant differences in the latencies of the Na and Pa waves or the Na-Pa amplitude for the experimental group, but electrode or ear effects were present in 87.5% of group A and 58.8% of group B. Overall, differences observed tended to be small (by clinical diagnostic standards), yet suggest that children with PKU exhibit some effect of this disorder on the pontine auditory pathway, even when diagnosed/treated early and independent of the appropriateness of diet. It thus seems prudent to follow PKU children with auditory processing assessments to evaluate functional implications of these findings.

Audiological findings in Williams syndrome: A study of 69 patients

The aim of this study was to investigate, in a clinical setting, the auditory function of a group of individuals affected by Williams syndrome (WS). Sixty-nine patients with WS, aged 2-30, underwent comprehensive audiological testing including air/bone conduction behavioral audiometry, speech audiometry, tympanometry and measurement of the acoustic reflex, transient evoked otoacoustic emissions and brainstem auditory evoked responses. Hearing loss, defined by a pure-tone average above 15 dB HL, affected 22.6% of the patients studied with traditional audiometry and was mostly slight in severity. Hearing loss was conductive in 9.4% of patients, mainly children with otitis media with effusion, and sensorineural in 13.2% of patients. However, 30% of the ears studied had a hearing impairment in the high frequency range (high-frequency pure-tone audiometry above 15 dB HL), higher in participants above 15 years (46.15%) than in the younger ones (23.45%). Contralateral stapedial reflexes were present in all patients with A-type tympanograms. Transient otoacoustic emissions were absent in 44% of the ears of patients with normal hearing. Brainstem auditory evoked responses fell within normal ranges thus confirming the absence of retrocochlear dysfunction. Although hearing loss does not seem to be frequent, a cochlear fragility, especially in the high frequency range, related to outer hair cells is characteristic of WS. Therefore we strongly recommend monitoring patients affected by WS using annual audiometric tests and performing otoacoustic emissions in order to identify a subclinical cochlear dysfunction which might benefit from an audiological follow up before the possible onset of hearing loss.

Change of Stapedial Reflex Threshold according to the Depth of Intravenous Propofol Anesthesia

Background and Objectives : Stapedial reflex (SR) threshold is of considerable diagnostic significance in the evaluation of audiological function, especially under sedation or general anesthesia since anesthetic drugs often act on neurotransmitters or neuromodulators. The aim of this study was to evaluate the changes in the SR threshold according to the depth of anesthesia. Subjects and Method : Sixty patients with normal hearing who were scheduled for operation under general anesthesia were included in this study. Anesthetic agent used was propofol and the depth of anesthesia was monitored by the bispectral index (BIS). SR was measured five times according to depth of anesthesia. Results : Both ipsilateral and contralateral SR thresholds were increased according to the depth of anesthesia using propofol. In particular, ipsilateral SR showed no response at BIS 60 and contralateral SR at BIS 40. However, there were no significant differences between age groups and gender. Conclusion : Propofol significantly increased both ipsilateral and contralateral SR threshold according to depth of anesthesia. When it is necessary to measure SR under general anesthesia, we should consider the effect on SR threshold according to the depth of anesthesia.

Effects of stapedial arch fractures on conductive hearing loss and stapedial reflexes.

It has been stated in the clinical literature that stapedial fractures could produce a significant conductive hearing loss while leaving the contralateral stapedial reflex intact. The objective of this study is to test this hypothesis in an animal model. Nine hooded rats underwent acoustic-stapedial reflex (ASR) and cochlear microphonic (CM) threshold determinations before and after middle ear surgery. An argon laser was used to divide the tensor tympani tendon, the anterior stapedial curs, and the posterior stapedial crus, sequentially. The initial functional measures were repeated after each laser procedure to document its effect. Dividing the tensor tympani tendon and the anterior stapedial crus had variable and small effects on ASR and CM thresholds. Division of the second (posterior) crus eliminated stapedial reflexes and produced a significant hearing loss. This study refutes the hypothesis that fracture of one (anterior) stapedial crus will significantly alter ossicular sound transmission, but it supports the hypothesis that measured stapedial reflexes would not be significantly altered by a single crus fracture. Therefore, the surgeon exploring an ear for a conductive hearing loss with an intact contralateral stapedial reflex should look carefully for another source of the hearing loss if finding only a single stapedial arch fracture.

Contralateral acoustic stimulation induces a phase advance in evoked otoacoustic emissions in humans

In 28 normal-hearing human subjects, the medial olivocochlear efferent system was activated by contralateral acoustic stimulation which is able to mimic the inhibitory effects of electrical stimulation of the crossed olivocochlear bundle. A first experiment on 16 subjects demonstrated that a contralateral white noise of 35 dB SL was able to induce temporal changes on transiently evoked otoacoustic emissions in response to clicks of 63 dB SPL. These temporal changes consisted of an advance of click-evoked otoacoustic signals in 87% of cases and is referred to as phase-shift effect. The phase advance, quantified using two signal processing methods in both time and frequency domains, was found to be mainly associated with lower frequencies, with a maximal effect at 1.5 kHz and minimal effects around 3.5 and 4 kHz. In a second experiment, carried out on 12 subjects, a negative relationship was found to exist between the ipsilateral stimulation level (level of clicks ranging from 57 to 69 dB SPL) and the phase-shift effect (PSE). Specifically in the range of levels tested (25–45 dB SL), a linear relationship presenting no obvious saturation effect was observed between the contralateral level and the PSE. The PSE was examined in 6 additional subjects exhibiting pathological symptoms; 2 of 3 individuals, who had no contralateral stapedial reflexes unilaterally, showed the PSE whereas this response was reduced or absent in 3 other subjects in the ear with severed efferents associated with a vestibular neurotomy. The integrity of olivocochlear efferents was, therefore, necessary to obtain a full effect, but the absence of stapedial reflex did not prevent the effect from occurring.

Differential effects of glucocorticoids on human auditory perception

It is assumed that glucocorticoids and mineralocorticoids, the hormones produced by the adrenal cortex, act as modulators of central nervous functions in addition to their well known role in endocrine stress responses. More specifically, it has been suggested that adrenal corticoids cause changes in sensory thresholds. In two double-blind crossover studies we evaluated auditory perception in healthy volunteers after treatment with hydrocortisone, dexamethasone, and the respective placebos. Stapedial reflexes, pure tone and speech audiograms, and brainstem electric response audiometry served as the dependent variables. As circadian changes in the density and occupancy of the brain corticosteroid receptors have been postulated, we performed Study I in the morning and Study II in the evening. Treatment effects clearly varied with time of day. A differential effect of the two corticoids occurred on contralateral stapedial reflexes. These results parallel results obtained with gustatory stimuli, and suggest that glucocorticoids modulate sensory perception across modalities.

Kearns-Shy Syndrome: Report of a Case

A 52-year-old woman with Kearns-Shy syndrome was reported in regard to audiometric findings in her clinical course of five years' duration. The patient first noted a hearing loss at the age of 41, and it was slowly progressive. The first hearing test was performed at the age of 47, and a pure tone audiogram showed a moderate sensorineural hearing loss bilaterally, which was formed rather prominent above 1000Hz. At the age of 49, a pure tone audiometry revealed deterioration of bilateral hearing only at 250Hz and 500Hz. For the last three years, her hearing remained unchanged. Speech discrimination was extremely poor. Bekesy audiogram showed type II tracing according to the Jerger's classification. The contralateral stapedial reflexes could not be elicited for the pure tone signal (125dB HTL) at 500, 1000, 2000, 4000Hz. Although the lesion of the hearing loss was not determined, the author suggested that the hearing loss of this syndrome might result from cochleosaccular degeneration.

Adaptation of the acoustic reflex.

The characteristics of acoustic reflex adaptation were studied in human subjects. Contralateral stapedial reflex measurements were made by monitoring changes in acoustic conductance and susceptance with a 220-Hz probe. The reflex activators included four tonal stimuli (500, 1000, 2000, and 4000 Hz) and broadband noise presented for 180 s at 96, 104, and 112 dB SPL. The data are presented as change in acoustic admittance and in percent of maximum admittance change. The static admittance of the ear was found to drift systematically toward lower admittance values in the absence of contralateral stimulation. All stimulus conditions demonstrated some reflex adaptation. The half-life and time of onset of adaptation were found to vary directly with intensity and inversely with frequency. The effects of stimulus parameters on the rates of reflex adaptation are discussed. A previously described exponential model of reflex adaptation provided a reasonable first approximation to the data.

Some observations on the contralateral stapedial reflex artefact.

An artefact was observed whilst testing profoundly deaf children with a peters AP61c acoustic impedance meter, using the contralateral stapedial reflex technique at high stimulus levels. A study was carried out on cadavers which confirmed the earlier observation, and this pseudo-reflex was found to be caused by the transmission across the head of the stapedial reflex stimulus tone during contralateral testing. An electronic filter was designed and built which suppressed this artefact. It is suggested that this artefact could be mistaken for a stapedial reflex response.