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Clinical Test Paradigms and Problems: Human Otoprotection Studies
Published in Stavros Hatzopoulos, Andrea Ciorba, Mark Krumm, Advances in Audiology and Hearing Science, 2020
Colleen G. Le Prell, Kathleen C. M. Campbell
During electronystagmography (ENG), electrodes are placed above and below the eye and the measured electrical activity is used to measure the involuntary rapid eye movements, termed nystagmus, that occur in response to various stimuli. There are multiple types of ENG tests. These include a calibration test (assessing ability to follow a light stimulus from 40 to 48 in. away), a gaze test (measurement of nystagmus while eyes are fixed on a target), a pendulum tracking test (the ability to follow a light source as it moves like the pendulum of a clock), an optokinetic test (ability to follow a quickly moving light back and forth across visual field), and positional testing that involves moving the head and body. During head impulse/head thrust testing, the patient/participants head is quickly turned by the examiner, who watches the patient/participants eyes to monitor the “catch-up” nystagmus saccades. ENG testing also includes water caloric testing, during which warm, or cool, water or air is delivered into the ear canal. Videonystagmography (VNG) is similar to ENG but the movements of the eyes are directly measured using high-speed, lightweight video goggles to precisely quantify the velocity of these eye saccades, which increases the accuracy of the testing.
Common otology viva topics
Published in Joseph Manjaly, Peter Kullar, Advanced ENT Training, 2019
VOR suppression test: The brain is able to suppress the VOR when tracking a moving target with head and eyes moving together. Testing for this involves the patient's arms outstretched and being asked to fixate on thumbs whilst the patient's chair is oscillated. This can also be performed with VNG using a laser light. This is an assessment of the vestibulocerebellum, in particular the flocculus and paraflocculus, although it is a non-specific assessment.
Vestibular Neuritis
Published in John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed, Paediatrics, The Ear, Skull Base, 2018
The caloric test is the gold standard for diagnosing unilateral peripheral dysfunction, with a reduced or absent response on the affected side. In the study by Sekitani et al. 50% of patients with vestibular neuritis, investigated with the caloric test, were shown to have a partial canal paresis.2 Of note is that, when only the inferior nerve is affected, the caloric test, which depends largely on the horizontal canal function, is normal. The VNG/ENG recordings of eye movements allow a more detailed evaluation compared to the clinical examination, in addition to providing a record of the eye movements. A number of the standard battery of eye movement recordings help to identify a unilateral vestibular dysfunction, for example the gaze testing with identification of the typical peripheral nystagmus, but also central neurological pathologies can be identified (typically cerebellar lesions).26 The rotatory chair (used in combination with VNG or ENG) is the gold standard for diagnosis of bilateral vestibular loss. The standard test battery can also identify a peripheral vestibular asymmetry.26
Evaluating the Vestibulo-Ocular Reflex Following Traumatic Brain Injury: A Scoping Review
Published in Brain Injury, 2021
Adrienne Crampton, A. Garat, H. A. Shepherd, M. Chevignard, K. J. Schneider, M. Katz-Leurer, I.J. Gagnon
In this review, Videonystagmography (n = 14) was used to evaluate VOR gain, asymmetry and gaze stability (24,46,52–61). Certain studies simply added VNG equipment to provide objective measurement to a non-computerized clinical test protocol (i.e., HIT or HST wearing Frenzel goggles). Alternatively, many of the included VNG test batteries followed the protocol for administration developed by their manufacturer. While manufacturer protocols were often based upon existing clinical tests, heterogeneity was observed in many elements of their administration. Differences across tools included sampling frequencies (frequency of stimulation at which eye movements are recorded), number of repetitions administered (ranging from 5 to 30/side for the HIT), speeds at which gain values were recorded (40 ms, 60 ms, 80 ms), equipment set-up, lighting of environment, position of both evaluator and subject, distances from stimuli or fixation points, monocular versus binocular, and variables of interest (gain, asymmetry, general unspecified gaze stability).
The long-term follow-up of 61 horizontal canal BPPV after Gufoni and Barbecue maneuver: a prospective study
Published in Acta Oto-Laryngologica, 2020
Qingqing Dai, Qiurong Chen, Li Yin, Hong Zheng, Shi-Xi Liu, Maoli Duan
All patients have undergone otoneurotologic examination, cranial MRI, pure tone audiometric test, VNG viewing and recording (including Dix–Hallpike and Supine Roll test) without medication for at least three days before test, and fulfilled the detailed history questionnaires. All candidates were informed with a informed consent following all the guidelines for investigation with human subjects required by Ethics Committee of our hospital. The patients who agreed to sign it were included in the study. After the history taking, physical examinations and tests, some patients were excluded (Table 1). Sixty-two patients who agreed to do the treatment and signed the informed consent are investigated, including one who lost to follow-up for unknown reasons. The final number of participants is 61.
Nystagmus duration after caloric irrigations
Published in International Journal of Audiology, 2020
Charlotte Skipper, Richard Knight, Debbie Cane
The limitations of this study primarily surround the analysis of VNG traces on the software. Nystagmus was measured to a minimal level (2° s−1) but had not technically stopped, as it was difficult in practice to obtain results at 0° s−1 for all patients using the software, and it was thought that this may lead to inaccurate measurements. Even using 2° s−1, it was still challenging in cases where a CTC nystagmus was present, and results then needed to be recorded down to 1 or 0° s−1. It was also decided that a nystagmus beat beyond 10 s of the previous was ‘isolated’ and therefore not measured, but it is possible that a small amount of nystagmus could have been missed this way. Some recordings were also ‘noisy’ and therefore more difficult to analyse compared to others. Only one researcher was used to analyse the traces for nystagmus duration, although some were checked against another clinician’s judgement. The subjective perception of dizziness was not measured during or after testing, which may vary between individuals and persist for longer in some than others (Jacobson et al. 2018; Mijovic et al. 2017).