Background and Aim: Vestibular evoked myogenic potential (VEMPs) is one of the clinical tools to evaluate vestibular function. The VEMPs can be recorded from sternocleidomastoid muscle by auditory stimulation with various sound stimuli and are thought to have saccular origin. The aim of this study was to compare the VEMP responses evoked by short (500 Hz) tone burst (STB) with those evoked by click stimuli in healthy young individuals.          

Materials and Methods: Thirty healthy volunteers (15 males, 15 females) with ages of 18 to 30 years were enrolled in this study. Subjects were instructed to sit on a chair and rotate their head to the opposite side of the recording muscle. The VEMPs was recorded using 500 Hz STB and then click sound stimuli to each ear. The p13 and n23 latencies, p13-n23 peak-to-peak amplitude and VEMPs thresholds were obtained for further analysis.       

Results: The VEMP responses were present in all subjects for STB and ware not recorded in one subject for click. The latencies of p13 and n23 of STB-VEMP were significantly longer, and the p13- n23 amplitudes were significantly greater for STB-VEMP (p<0.05), and thresholds were higher for clicks (p < 0.05). No significant difference was obtained between both ears and genders. (p > 0.05).

Conclusion: The VEMP responses were significantly different between the stimuli of STB and click, and the norms of different stimuli should be established for clinical interpretations. According to these data, we recommend STB stimuli in comparison with clicks for clinical diagnosis.

Background and Aim: Vestibular evoked myogenic potential in response to click or short tone burst stimuli have been used as a clinical test for distinguish saccule and inferior vestibular nerve diseases. Different studies show that cochlear implant could have inverse effects on vestibular structures. We aimed to investigate vestibular evoked myogenic potential in unilateral cochlear implanted individuals in compare to normal individuals.
Methods: Thirty-three unilateral cochlear implanted patients (mean age 19.96 years) and 30 normal hearing individuals (mean age 24-27 years) as control group were enrolled in this cross- sectional study. Absolute latencies and amplitudes of myogenic potential responses were measured and compared in both groups.
Results: Myogenic potential recorded in both ears of all controls were normal. No response could be recorded in 16 patients (48.48%) from both ears. In three patients, responses were recorded in both ears though the amplitude of waves was reduced in implanted ear. Unilateral response could be recorded in 14 patients only in their non-implanted ear.
Conclusion: Vestibular evoked myogenic potential test is a useful tool for assessing saccular function in cochlear implant patients. Damages of osseous spiral lamina and basilar membrane after cochlear implantation could result in dysfunctions of vestibular organs specially saccule. It seems that saccule could be easily damaged after cochlear implantation. This would cause absence or reduced amplitudes in myogenic potential.

Background and Aim: High incidence of speech disorders in children with cerebral palsy could be related to a deficiency in processing of auditory stimuli. So it is vital to check out any peripheral or central disorders in auditory system using behavioral and electrophysiological auditory tests.
Methods: In a cross-sectional study, 15 children with spastic diplegia, mean age 5.77, SD 2.26 years, and 15 normal children, mean age 5.33, SD 1.80 years, were tested using pure tone audiometry, immittance and auditory brainstem responses. The results were compared between the two groups.
Results: Hearing thresholds and middle ear status were in normal range in all participants however, contralateral acoustic reflex thresholds were mostly elevated. Comparing absolute latency and interpeak latency intervals of auditory brainstem responses between the two groups, absolute latency interval of later waves, and in specific the V wave, was significantly longer in diplegic children (p=0.04) resulting in a longer III-V interpeak latency intervals (p=0.02).
Conclusion: Neurological disorders in ponto-reticulo-spinal pathway, pontine reticular nuclei and upper pons which are adjacent to auditory nuclei of lateral leminiscus and inferior colliculus result in auditory dys-synchrony and increased latency intervals in latter waves of auditory brainstem responses. This could also attributed to functional disorders in wave-generating sites in these patients.

Background and Aim: Research conducted since the early 1900s has consistently identified differences between deaf and hearing children on performance of a wide variety of motor tasks, most notably balance. Our study was performed to test static and dynamic balance skills in congenital severe to profound hearing impaired children in comparison with normal age-matched children.
Methods: This cross-sectional study was conducted on 30 severe to profound hearing impaired and 40 normal children with age 6 to 10 years old. Bruininks-Oseretsky test of motor proficiency 2, balance subset with 9 parts was used for evaluation of balance skills.
Results: Hearing-impaired children showed 16.7 to 100% fail results in 7 parts of the balance subset. In normal children fail result was revealed just in 3 parts of the balance subset from 2.5 to 57.5%, and differences between two groups were significant (p<0.0001). There was a significant difference between two groups in two static balance skills of standing on one leg on a line and standing on one leg on a balance beam with eyes closed (p<0.0001).
Conclusion: It seems that development of static balance skills are longer than dynamic ones. Because severe to profound hearing-impaired children showed more weakness than normal children in both static and dynamic balance abilities, functional tests of balance proficiency can help to identify balance disorders in these children.

Background and Aim: Vestibular evoked myogenic potentials and acoustically evoked short latency negative response are two non-cochlear responses with probably saccular origin. The present study was conducted to determine the percentage of presence and the relation between these two responses in children with hearing loss.
Methods: Thirty children with profound congenital sensorineural hearing loss were studied.  Vestibular evoked myogenic potentials ellicitedby tone burst stimuli and acoustically evoked short latency negative response ellicited by click stimuli were recorded. Both responses were recorded at air conduction threshold level monaurally via an internal receiver.
Results: Vestibular evoked myogenic potentials in 53.3% of children and acoustically evoked short latency negative response in 40.0% of cases were recorded. There was a significant correlation between the percentage of recording these two responses (p=0.005). Gender and the stimulated ear had no effect on the results.
Conclusion: In almost half of these disabled children, both vestibular evoked myogenic potentials and acoustically evoked short latency negative response were recoreded. This finding may both indicate that hearing loss has no effect on the function of otolith organs in some children and vestibular deficits probably exist along with hearing impairment in others. This findng reiterates the importance of evaluation of vestibular system as part of standard auditory evaluations.

Background and Aim: Cervical vestibular-evoked myogenic potential (cVEMP) is one of the diagnostic tests used in assessing vestibular function. Two aims of this study were to investigate implications of cervical vestibular evoked myogenic potential in children with spastic cerebral palsy (7-12 years), and to compare vestibular function in these children and normal children.

Methods: In this cross-sectional study, myogenic potential was recorded in 31 children with spastic cerebral palsy (8 girls, 23 boys,7-12 years of age, with mean age of 8.77 years old and standard deviation of 1.52 years) and 31 normal children (13 girls, 18 boys with mean age of 8.77 years and standard deviation of 1.52 years). Cervical vestibular evoked myogenic potential was recorded with 500 Hz tone burst. The recorded parameters included p13 and n23 latency, p13-n23 pick to pick amplitude, and threshold.

Results: Myogenic Potential was recorded in 31 normal children. They had bilateral responses. In children with cerebral palsy, 21 children showed bilateral responses, 3 children had only right-sided responses, 8 children had only left-sided responses, and two children did not show any responses. The statistical significant differences were shown between the two groups in n23, p13-n23 pick to pick amplitude, and threshold (p<0.05).

Conclusion: These findings showed that cervical vestibular evoked myogenic potential can be used in children with cerebral palsy. There were significant differences in myogenic potential parameters between the two groups. More studies are needed to investigate the causes of these differences.