Vestibular involvement in adults with HIV/AIDS.

OBJECTIVE: HIV/AIDS is responsible for widespread clinical manifestations involving the head, and neck. The prevalence and nature of vestibular involvement is still largely unknown. This study, aimed to describe and compare the occurrence and nature of vestibular involvement among a group of, adults infected with HIV compared to a control group. It also aimed to compare the vestibular function, of symptomatic and asymptomatic HIV positive adults who receive antiretroviral (ARV) therapies to, subjects not receiving ARV. METHODS: A cross-sectional study was conducted on 53 adults (29 male, 24 female, aged 23-49 years, mean=38.5, SD=4.4) infected with HIV, compared to a control group of 38 HIV negative adults (18, male, 20 female, aged 20-49 years, mean=36.9, SD=8.2). A structured interview probed the subjective, perception of vestibular symptoms. Medical records were reviewed for CD4+ cell counts and the use of, ARV medication. An otologic assessment and a comprehensive vestibular assessment (bedside, assessments, vestibular evoked myogenic potentials, ocular motor and positional tests and bithermal, caloric irrigation) were conducted. RESULTS: Vestibular involvement occurred in 79.2% of subjects with HIV in all categories of disease, progression, compared to 18.4% in those without HIV. Vestibular involvement increased from 18.9% in CDC category 1 to 30.2% in category 2. Vestibular involvement was 30.1% in category 3. There were, vestibular involvement in 35.9% of symptomatic HIV positive subjects, and 41.5% in asymptomatic, HIV positive subjects. There was no significant difference in the occurrence of vestibular involvement, in subjects receiving ARV therapies compared to those not receiving ARV therapies (p=.914; chi-square, test). The odds ratio indicates that individuals with HIV have a 16.61 times higher risk of developing, vestibular involvement during their lifetime of living with the disease and that it may occur despite, being asymptomatic. CONCLUSION: Vestibular involvement was significantly more common in subjects with HIV. Primary health care providers could screen HIV positive patients to ascertain if there are symptoms of vestibular involvement. If there are any, then they may consider further vestibular assessments and subsequent vestibular rehabilitation therapy.

Clinical usefulness of the rotatory, caloric, and vestibular evoked myogenic potential test in unilateral peripheral vestibular pathologies.

OBJECTIVE: The aim of this study was to investigate the diagnostic capacity of three different rotatory tests, and to investigate the clinical effectiveness of the caloric, rotatory, and vestibular evoked myogenic potential (VEMP) test. DESIGN AND STUDY SAMPLE: Several rotatory tests--sinusoidal harmonic acceleration test (SHAT), pseudorandom rotation test (PRRT), velocity step test (VST)--and a caloric and a VEMP test, were given to 77 patients (mean age 52 years) with a unilateral peripheral vestibular pathology, and 80 control subjects (mean age 48 years). RESULTS: For the rotatory test, the highest diagnostic capacity was obtained with the 0.01 Hz SHAT frequency, followed by 0.1 and 0.05 Hz. A higher diagnostic accuracy was reached for the caloric and VEMP test. The caloric test demonstrated high sensitivity and specificity values, but the 0.01 Hz SHAT rotation appeared more sensitive, and the VEMP more specific, than the caloric test. CONCLUSION: A selection of the 0.01, 0.05, and 0.1 Hz SHAT rotations is suggested as the most ideal rotatory test protocol, and a combination of rotatory, caloric, and VEMP testing will result in a more complete examination of our vestibular system.

Determination and evaluation of clinically efficient stopping criteria for the multiple auditory steady-state response technique.

OBJECTIVE: The present study aimed at establishing clinically efficient stopping criteria for a multiple 80-Hz auditory steady-state response (ASSR) system. METHODS: In Experiment 1, data of 31 normal-hearing subjects were analyzed off-line to propose stopping rules. Consequently, ASSR recordings will be stopped when (1) all 8 responses reach significance and significance can be maintained for 8 consecutive sweeps; or (2) the mean noise levels were 4nV (if p-values were between 0.05 and 0.1, measurements were extended once by 8 sweeps); or (3) a maximum amount of 48 sweeps was attained; whichever occurred first. In Experiment 2, these stopping criteria were applied on 10 normal hearing and 10 hearing-impaired adults to assess the efficiency. RESULTS: The application of these stopping rules resulted in ASSR threshold values that were comparable to other ASSR research. Furthermore, preliminary analysis of the response and noise amplitudes demonstrated slightly higher values for hearing impaired than normal-hearing subjects. CONCLUSIONS: The proposed stopping rules can be used in adults to determine accurate ASSR thresholds within a time-frame of about 1h. SIGNIFICANCE: The use of these a priori stopping criteria might assist the clinician in their decision to terminate ASSR recordings.

The effect of age on the sinusoidal harmonic acceleration test, pseudorandom rotation test, velocity step test, caloric test, and vestibular-evoked myogenic potential test.

OBJECTIVES: Age-related anatomical and morphologic vestibular deterioration has already been elaborated. Demonstrating a corresponding degradation in physiologic function, however, entails a much higher challenge. The objective of this study was to investigate age-related changes using rotational tests, caloric tests, and the vestibular-evoked myogenic potentials (VEMP) test. DESIGN: Eighty healthy human subjects (38 men and 42 women) ranging in age from 18 to 80 yrs participated in this study and were subjected to an extensive vestibular test battery. Function tests included sinusoidal harmonic acceleration tests, a pseudorandom rotation test, velocity step tests, a caloric test, and a VEMP test. RESULTS: No significant age trends were noted for the sinusoidal harmonic acceleration test and velocity step tests response parameters, in contrast to subtle decreasing gain values with advancing age for the pseudorandom rotation test. Increasing slow-component velocity values were measured with the caloric test, whereas the frequency parameter showed no relevant age changes. The largest age trends were detected with the VEMP, with decreasing amplitudes, increasing thresholds, and decreasing N1 latencies. All asymmetry parameters remained stable across the different age categories. CONCLUSIONS: Only subtle age changes could be demonstrated with the rotational and caloric tests, in contrast to more pronounced age trends with the VEMP.

The clinical value of the multiple-frequency 80-Hz auditory steady-state response in adults with normal hearing and hearing loss.

OBJECTIVES: To determine the ability of the air-conduction multiple-frequency auditory steady-state response (ASSR) technique to diagnose normal hearing (NH) and mild and moderate degrees of sensorineural hearing loss (SNHL), to assess patients with conductive hearing loss (CHL), to evaluate flat and sloping configurations of hearing impairment, and to provide sensitivity and specificity values for various ASSR cutoff criteria. DESIGN: A comparative study between ASSR and criterion-standard behavioral thresholds. SETTING: Ear, nose, and throat department at a university hospital. PATIENTS: The study population comprised 40 adults with NH, 17 with SNHL, and 7 with CHL. MAIN OUTCOME MEASURES: The measure of interest was the difference between ASSR and behavioral thresholds at 0.5, 1.0, 2.0, and 4.0 kHz. The sensitivity, specificity, positive predictive value, negative predictive value, and efficiency were calculated for several ASSR cutoff criteria. RESULTS: The ASSR technique clearly distinguished moderate SNHL from NH, but the "mild SNHL and NH" and "mild SNHL and moderate SNHL" differentiation was particularly difficult at 0.5 and 2.0 kHz, respectively. Air-conduction ASSR thresholds accurately predicted behavioral thresholds in CHL. The ASSR system precisely reflected the flat and sloping configurations. Finally, the most appropriate ASSR cutoff point for normality seems to be the 30-dB-or-lower criterion. CONCLUSIONS: In adults, the multiple-frequency 80-Hz ASSR technique can be used to determine the degree and configuration of hearing loss. Although air-conduction ASSR thresholds accurately predicted behavioral thresholds in CHL, future research with bone-conduction ASSRs is necessary to establish the type of hearing loss. Furthermore, the applicability of these findings still needs to be confirmed for infants.

The vestibular evoked myogenic potential: a test-retest reliability study.

OBJECTIVE: The purpose of this study was to evaluate the reliability of the vestibular evoked myogenic potential (VEMP) response in a clinical setting when only a feedback mechanism is available for monitoring background EMG. METHODS: Sixty-one healthy subjects participated in the investigation of the within-session reliability, whereas fourteen of them were retested after one week for examination of the between-session reliability. VEMPs were recorded using 500 Hz tone bursts with the subjects in a sitting position and their heads turned away from the test ear to the contralateral shoulder, thereby pushing their chin against the inflatable cuff of a blood pressure manometer, serving as feedback method. RESULTS: The feedback method revealed latency and amplitude values comparable to other data in the literature where different test conditions were applied. Excellent reliability with ICC values ranging from 0.78 to 0.96 and CV(ME) values ranging from 4% to 36%, was achieved for P1 and N1 latency, threshold and interpeak amplitude. Good reliability with ICC values of 0.65 and 0.68 and CV(ME) values of 170% and 189%, was obtained for the asymmetry ratio. CONCLUSIONS: A unilateral muscle contraction controlled by a feedback mechanism resulted in reliable response parameters, comparable right to left and corresponding to literature data obtained in different test conditions. SIGNIFICANCE: The use of a blood pressure manometer as feedback mechanism combined with a meticulously controlled positioning of the head and contraction of the SCM muscle provides a reliable alternative in clinical settings, when the background muscle contraction cannot be measured or software related correction algorithms are not accessible.

Auditory steady-state responses in normal hearing adults: a test-retest reliability study.

The test-retest reliability of the auditory steady-state response (ASSR) has received limited attention. Therefore, the aim was to assess the test-retest reliability of an 80-Hz multiple-ASSR system in normal-hearing subjects by a comprehensive set of statistical methods. Twenty-nine participants (15 females) aged between 18 and 30 years contributed to two sessions (test-retest), and the ASSR thresholds were determined with a descending search protocol using a 10-dB precision. The test-retest reliability was assessed by a three-layered approach which consisted of Pearson product-moment correlation, analysis of variance (ANOVA), and standard error of measurement (SEM). The correlations for ASSR thresholds ranged from poor (0.34) for 500 Hz CF to moderate (0.55) for 1000, 2000, and 4000 Hz CF. A two-way ANOVA of the difference scores (ASSR threshold minus behavioral threshold) demonstrated no significant difference between test and retest. The SEM determined the normal tolerance for clinical error of repeated thresholds and the ASSR SEM values fell well within +/-10 dB HL. This investigation shows that the multiple ASSR-technique produces a clinically acceptable test-retest reliability for normal-hearing adults.

Normative data and test-retest reliability of the sinusoidal harmonic acceleration test, pseudorandom rotation test and velocity step test.

Rotational testing has been used in clinical practice to explore vestibular function. Frequently used stimulus algorithms include: sinusoidal harmonic acceleration test (SHAT), pseudorandom rotation test (PRRT), and velocity step test (VST). The aim of this study was to construct normative data as well as to evaluate the test-retest reliability of those rotational paradigms. One hundred and fifty subjects without vestibular history participated in the normative study. The SHAT was presented at 5 frequencies (0.01, 0.02, 0.05, 0.1, 0.2 Hz), whereas for the PRRT those frequencies were summed. The VST consisted of a rotation to the right and left and was administered twice. Thirty-two volunteers were retested to assess the test-retest reliability. Separate normative data were needed according to sex, stimulus type, and frequency for the SHAT and PRRT, and according to stimulus and direction for the VST. High reliability by means of the intraclass correlation coefficient (ICC) and the method error (ME) was obtained for the SHAT, PRRT, and VST gain, SHAT phase and asymmetry, and VST time constant parameters. The availability of data on the minimal detectable test-retest differences supports the evaluation of rotational responses on a retest session.

Auditory steady-state responses to MM and exponential envelope AM(2)/FM stimuli in normal-hearing adults.

The present study utilized a commercially available multiple auditory steady-state response (ASSR) system to test normal hearing adults (n=55). The primary objective was to evaluate the impact of the mixed modulation (MM) and the novel proposed exponential AM(2)/FM stimuli on the signal-to-noise ratio (SNR) and threshold estimation accuracy, through a within-subject comparison. The second aim was to establish a normative database for both stimulus types. The results demonstrated that the AM(2)/FM and MM stimulus had a similar effect on the SNR, whereas the ASSR threshold results revealed that the AM(2)/FM produced better thresholds than the MM stimulus for the 500, 1000, and 4000 Hz carrier frequency. The mean difference scores to tones of 500, 1000, 2000, and 4000 Hz were for the MM stimulus: 20+/-12, 14+/-9, 10+/-8, and 12+/-8 dB; and for the AM(2)/FM stimulus: 18+/-13, 12+/-8, 11+/-8, and 10+/-8 dB, respectively. The current research confirms that the AM(2)/FM stimulus can be used efficiently to test normal hearing adults.

Water irrigation versus air insufflation: a comparison of two caloric test protocols.

The aim of the present study was to construct and compare two caloric test protocols, one for water irrigation, and one for air insufflation. A set of reference data was constructed and tabulated as well as the intersubject variability. The effect of age, sex, ear, and temperature, as well as a possible priming effect and order effect were investigated. Forty-seven subjects (18-58 years) without otological or vestibular history participated. Four response parameters were investigated: slow component velocity (SCV), frequency, unilateral weakness (UW), and directional preponderance (DP). Statistically higher SCV values were obtained for water compared to air, with statistically higher standard deviations for SCV water values. No influences of age, sex, ear, or temperature could be demonstrated on any of the response parameters. The same applied for the presence of an order effect and a priming effect. Comparing the two protocols to one another led the present authors to favour water as the standard irrigation medium, and air only in situations where water is contra-indicated.

Distortion product otoacoustic emissions: an objective technique for the screening of hearing loss in children treated with platin derivatives.

In order to develop a sensitive audiometric protocol for identifying ototoxicity in children, a retrospective study of 16 children treated with cisplatin and/or carboplatin was performed. Audiometric testing was done by means of pure-tone threshold audiometry (PTA), high-frequency audiometry (HFA), and distortion product otoacoustic emissions (DPOAEs). Cisplatin caused a sensorineural high-frequency hearing loss in the study group compared to the controls (p < 0.01). Sixty-six percent of the cisplatin patients had a grade 2 or 3 ototoxicity. However, ototoxicity was not found in the patients treated with carboplatin. An excellent correlation was found between DPOAE levels and results obtained by audiometry (r = 0.82). Patients exposed to cisplatin are at significant risk for the development of drug-induced sensorineural hearing loss. Because of the several advantages of DPOAEs (noninvasive, objective, rapid, easy to use, sensitive) this method should be added in the audiological follow-up in infants and toddlers.

Comparison of the overall intelligibility, articulation, resonance, and voice characteristics between children using cochlear implants and those using bilateral hearing aids: a pilot study.

The purpose of this study was to determine and to compare the overall intelligibility, articulation, resonance, and voice characteristics in children using cochlear implants (CI) and children using conventional hearing aids (HA). Nine prelingually deaf children using CI and six children with a prelingual severe hearing loss using HA, were selected to participate. Objective (DSI, nasalance scores) as well as subjective assessment techniques (perceptual evaluations) were used. Both the CI and HA children demonstrated normal vocal quality and resonance but showed the presence of articulation disorders. In the CI children, intelligibility was significantly better compared to the HA children. Significantly more phonetic and phonological disorders were present in the HA children. The results of this study show a poorer intelligibility of the HA children in comparison with the CI children which is probably due to the occurrence of significantly more phonetic and phonological disorders. Future detailed analysis in a larger sample of CI and HA children may help further clarify the issue of speech and voice characteristics and may demonstrate an important prognostic value.