Red flags alerting a posterior cranial fossa tumor from audiovestibular perspectives - a review.

BACKGROUND: There is no comprehensive and up-to-date overview of audiovestibular approach to the posterior fossa tumors in the literature. OBJECTIVE: This paper reviewed the literature relating to tumors at the posterior cranial fossa to find red flags alerting a posterior fossa lesion from audiovestibular perspectives. METHODS: This review was developed from articles published in those journals listed on the journal citation reports. Through the PubMed database, Embase, Google Scholar, and Cochrane library, 60 articles were finally obtained based on the PRISMA guidelines for reporting reviews. RESULTS: The presence of one red flag indicates a positive predictive value of 33% for detecting a posterior fossa lesion. Clinical features, namely, 1) mid-frequency sudden sensorineural hearing loss (SNHL), 2) bilateral sudden SNHL, and 3) rebound nystagmus may indicate a posterior fossa lesion, representing one, two, and three red flags, respectively. CONCLUSION: Those with 1) mid-frequency sudden SNHL, 2) bilateral sudden SNHL, and 3) rebound nystagmus trigger one, two, and three red flags, respectively, alerting clinicians the possibility of a posterior fossa lesion, which warrant MR imaging to exclude life-threatening or treatable conditions. SIGNIFICANCE: Patients with posterior fossa tumors may have potential life-threatening outcome.

Role of conventional MD staging in modern era of hydrops MR imaging.

Objective/Hypothesis: This study correlated stage of Meniere's disease (MD) with MR imaging of endolymphatic hydrops (EH) to assess the role of MD staging in modern era. Study Design: Retrospective study. Methods: Fifty-four MD patients (60 ears) underwent an inner ear test battery and were further confirmed by MR imaging. Sixty MD ears were divided into stages I-IV, and hydrops MR images at each stage were compared. Results: Hydrops MRI demonstrated that EH at the cochlea with respective Grades 0/I/II were 3/7/1 ears for stage I, 0/5/3 ears for stage II, 1/6/26 ears for stage III and 0/2/6 ears for stage IV. Significant relationship was not identified between MD stage and grades of cochlear hydrops. Similarly, no significant relationship was shown between MD stage and grades of vestibular (saccular/utricular) hydrops. The optimal cutoff value of four-tone average for predicting severe type (Grade II-III) cochlear/vestibular EH was 48 dB, which was within the stage III. Hence, prevalence of severe type (Grade II) cochlear EH in stages III (79%) and IV (75%) was significantly higher than stages I (9%) and II (38%). Similarly, severe type saccular/utricular EH in stages III (64%) and IV (75%) also showed significantly higher than stages I (18%) and II (25%). Conclusion: Although conventional MD staging fails to correlate with the grades of EH on hydrops MRI, late-stage MD may indicate heightened EH severity in the cochlea and vestibule. Level of Evidence: 4.

Comparing the recurrence of audio-vestibular disorders following breakthrough infection of COVID-19 vs. those following vaccine administration.

PURPOSE: The term "breakthrough infection" of COVID-19 indicates that subjects who previously received COVID-19 vaccination became infected with COVID-19. This study compared the recurrence of audio-vestibular disorders following breakthrough infection of COVID-19 vs. those following vaccine administration. PATIENTS AND METHODS: Fifty patients with previous known audio-vestibular disorders visited our clinic due to recurrence of inner ear symptoms following breakthrough infection of COVID-19 and were assigned to Group A. Another 50 patients who had recurrent inner ear symptoms following COVID-19 vaccination were assigned to Group B for comparison. The post-breakthrough infection interval is defined from date of breakthrough infection to the onset of inner ear symptoms, while the post-vaccination interval means the time from date of vaccination to the onset of inner ear symptoms. These two intervals were calculated and then compared. RESULTS: The time from latest vaccination to the breakthrough infection of COVID-19 was 4 m (median), likely due to waning of IgG response. To the onset of inner ear symptoms, the post-breakthrough infection interval was 40d (median) for Group A, which was significantly longer than 10d (median) of the post-vaccination interval for Group B. CONCLUSION: The post-breakthrough infection interval (median, 40d) is significantly longer than the post-vaccination interval (median, 10d) to exacerbate pre-existing audio-vestibular disorders. The reason is probably because an interval of 40d is related to IgG peak response following COVID-19 breakthrough infection, while that of 10d is responsible for IgG production after COVID-19 vaccination.

The role of serum osmolality in Meniere's disease with acute sensorineural hearing loss.

OBJECTIVE: This study investigated the role of serum osmolality in Meniere's disease (MD) patients with acute sensorineural hearing loss (SNHL). DESIGN: Retrospective study. STUDY SAMPLES: Twenty definite MD patients with acute unilateral SNHL were treated with an osmotic diuretic (Isosorbide, 100 mL daily) and assigned to Group A. Another 20 age- and sex-matched definite MD patients with acute SNHL were not given Isosorbide and assigned to Group B. Both groups underwent audiometry and blood examination for serum osmolality before and after treatment. RESULTS: Group A revealed a significant increase in serum osmolality after treatment. The optimal cut-off values for increased serum osmolality in Group A were +1.5 mOSM/L for predicting hearing improvement at frequencies of 250-1000 Hz, and +2.5 mOSM/L at 2000-4000 Hz. Comparing increased levels of serum osmolality (> +2.0 vs. ≤ +2.0 mOSM/L), Isosorbide dosing at 3.0 L vs. 1.0 L, significantly differed in the odds ratio (OR). Isosorbide at a total dosage of 3.0 L thus improves the hearing threshold by >10 dB at frequencies of 250-2000 Hz. CONCLUSION: The Isosorbide at a total dosage of 3.0 L may increase serum osmolality by > +2.0 mOSM/L, and improve the hearing threshold for hydropic ears at least >10 dB at low- and mid-frequencies.

Vertigo/dizziness following COVID-19 vaccination.

PURPOSE: This study assessed the vertigo/dizziness in patients following COVID-19 vaccination. PATIENTS AND METHODS: From July 2021 to June 2022, totaling 50 patients with dizzy spells following COVID-19 vaccination by AZ (AstraZeneca-Oxford University, AZD1222), BNT (Pfizer-BioNTech, BNT162b2) or Moderna (Moderna, mRNA-1273) vaccine were enrolled in this study. The interval from vaccination to the onset of vertigo/dizziness was compared with inter-episodic interval of vertigo/dizziness in the same patients, but without vaccination, during past one year (2020). RESULTS: The incidences of severe systemic complication per 106 shots were 0.86 for Moderna vaccine, 1.22 for AZ vaccine, and 1.23 for BNT vaccine. Conversely, rate of post-vaccination vertigo/dizziness was noted in the Moderna group (66 %), followed by the AZ group (20 %) and the BNT (14 %) group, meaning that type of COVID-19 vaccine may affect various organ systems. The median time to the onset of vertigo/dizziness following vaccination is 10d, which is consistent with the onset of IgG production, and significantly less than inter-episodic interval (84d) in the same patients without vaccination. CONCLUSION: Post-vaccination vertigo/dizziness can manifest as exacerbation of previous neurotological disorder. The median time to the onset of vertigo/dizziness following COVID-19 vaccination is 10d. Since the outcome is fair after supportive treatment, the immunomodulatory effect of the vaccines does not undermine the necessity of the COVID-19 vaccination.

Evolution of geriatric Meniere's disease during the past two decades.

BACKGROUND: This study compared the incidence of Meniere's disease (MD) in the elderly aged >65 years between the first (2001-2010) and second (2011-2020) decades to investigate the evolution of geriatric MD. METHODS: Totally, 1605 and 2550 patients with definite MD were experienced at the neurotological clinic during the first and the second decades, respectively. All patients were divided into three groups by 30-year age band, namely elderly (aged 65-94 years), adult (aged 35-64 years) and young (aged 5-34 years) groups, and underwent an inner ear test battery. Factors relating to the incidence of MD during the past two decades were analyzed. RESULTS: The elderly MD group comprised 198 (12.4%) of 1605 MD cases during the first decade, and 463 (18.2%) of 2550 MD cases during the second decade, showing a significantly increased incidence of elderly MD. Correlation between annual life expectancy (x) in Taiwan and annual prevalence (y) of the elderly MD in relation to total MD cases revealed y = 0.023x - 1.660 via linear regression analysis. In contrast, the adult MD group significantly differed in terms of age and gender ratio, but not incidence, between the two decades. Conversely, the young MD group exhibited significantly decreased incidence from the first decade (22.3%) to the second decade (13.8%). CONCLUSION: Evolution of geriatric MD during the past two decades reveals an increased incidence of the elderly MD patients, likely due to increased life expectancy coupled with altered life style.

Limitation of updated MR images on the vestibular hydrops in Meniere's disease.

PURPOSE: This study adopted the cervical and ocular vestibular-evoked myogenic potential (cVEMP and oVEMP) tests in Meniere's disease (MD) patients to correlate them with vestibular endolymphatic hydrops (EH) on MR images. METHODS: A total of 25 patients with unilateral definite MD identified by positive cochlear hydrops on MR images were enrolled. All patients underwent audiometry, cVEMP test and oVEMP test, followed by MR imaging for confirmation. RESULTS: A significantly declining sequence of abnormality rates in MD patients was identified from the audiometry (92%), cVEMP test (52%) to the oVEMP test (40%), which was consistent with a significantly decreasing order of prevalence of EH on MR images running from the cochlea (100%), saccule (56%) to the utricle (52%). The cVEMP test for detecting the saccular hydrops revealed a sensitivity of 62%, while the oVEMP test for assessing the utricular hydrops showed a sensitivity of 70%. However, correlating VEMP results with vestibular hydrops did not show any significant relationship. In addition, mean hearing level (MHL) at four frequencies (500, 1000, 2000, and 3000 Hz) of Grade I cochlear hydrops (51 ± 19 dB) did not significantly differ from Grade II cochlear hydrops (53 ± 19 dB). CONCLUSION: Limitations of the updated MR imaging for visualizing the hydrops comprised: (1) failure to correlate vestibular hydrops with VEMP results, and (2) failure to correlate grade of cochlear hydrops with MHL. The reason is probably because updated MR imaging fails to identify distorted contour of the cochlea/utricle/saccule. Further advanced technique using ultrahigh resolution of fine structures in the inner ear compartments is essential to promote a wider use of MR imaging.

Correlating atmospheric pressure and temperature with Meniere attack.

OBJECTIVE: This paper correlated the Meniere attack with meteorological parameters i.e. atmospheric pressure, temperature, relative humidity and rainfall, to investigate which parameters that trigger the Meniere attack. METHODS: During the past three years, totally 283 (2015), 351 (2016) and 319 (2017) patients with Meniere's disease (MD) were encountered at a clinic of the university hospital, accounting for 13%, 17% and 16% incidence in relation to overall annual neurotological cases, respectively. The onset of Meniere attack was then correlated with meteorological parameters. RESULTS: The mean seasonal incidence of Meniere attack in relation to overall seasonal neurotological cases in 2015-2017 were 14.8 ± 2.8% (spring), 17.5 ± 2.2% (summer), 16.0 ± 1.8 % (autumn) and 12.8 ± 2.0% (winter), indicating that summer season had a higher incidence of Meniere attacks than winter season. Onset of Meniere attacks correlated significantly with the atmospheric pressure (r = -0.4484, p = 0.0061) and temperature (r = 0.4736, p = 0.0035), and the atmospheric pressure was highly negatively correlated with the temperature (r = -0.9421, p < 0.0001). In contrast, no correlation was identified between the onset of Meniere attacks and relative humidity or rainfall. The atmospheric pressure in the same month with typhoon compared with that without typhoon revealed a median reduction of 13.1 hectopascal. CONCLUSION: Atmospheric pressure and temperature are correlated with the onset of Meniere attack. Summer season has a higher incidence of Meniere attack than winter season, likely because low atmospheric pressure in summer may aggravate endolymphatic hydrops, especially when accompanied by typhoons in the northwest Pacific region.

Post-irradiation endolymphatic hydrops vs. post-irradiation sudden deafness.

BACKGROUND: Increasing numbers of acute sensorineural hearing loss (SNHL) are recently experienced in irradiated nasopharyngeal carcinoma (NPC) survivors. AIM: This study adopted MR imaging to differentiate between post-irradiation sudden deafness (PISD) and post-irradiation endolymphatic hydrops (PIEH) in long-term NPC survivors with acute SNHL. METHODS: From 2012 to 2021, consecutive 10 irradiated NPC survivors with acute SNHL were enrolled. All patients underwent an inner ear test battery and MR imaging using HYDROPS-Mi2 technique. Six patients (11 ears) with positive cochlear hydrops on MR images were diagnosed as PIEH, while another 4 patients (4 ears) without cochlear hydrops on MR images were referred to PISD. RESULTS: The interval from the onset of NPC to acute SNHL did not significantly differ between the PIEH (10 ± 6 years) and PISD (8 ± 2 years). No significant difference was found between the two disorders from any of the symptomatic, radiotherapeutic, audiological, or vestibular perspective. Interestingly, most (5/6) patients with PIEH had bilateral involvement, while all (4/4) patients with PISD showed unilateral affliction. A significantly declining sequence of abnormality rates in the inner ear test battery was noted in the PIEH patients, running from the audiometry (100%), cervical vestibular-evoked myogenic potential (VEMP) test (100%), ocular VEMP test (73%), to the caloric test (36%). However, such declining trend was not observed in patients with PISD. CONCLUSION: When facing an NPC survivor who had acute SNHL over a prolonged period after irradiation, MR imaging using HYDROPS-Mi2 technique should be performed to differentiate the PIEH from the PISD, since both disorders have various treatment modalities and hearing outcome.

Predicting positive cochlear endolymphatic hydrops on magnetic resonance images.

Objective/hypothesis: This study correlated audiological results with magnetic resonance (MR) images to predict positive cochlear endolymphatic hydrops (EH) on MR images in patients with Meniere's disease (MD). Study design: Retrospective study. Methods: Twenty definite MD patients with positive cochlear EH on MR images were assigned to Group A. Another 20 definite MD patients with negative cochlear EH on MR images were assigned to Group B. All patients underwent an inner ear test battery followed by MR imaging using HRDROPS-Mi2 technique. Results: The mean hearing levels (MHLs) at frequencies of 125, 250, 500 and 1000 Hz revealed significantly worse in Group A than Group B. Significantly deteriorated MHLs were noted from Grades 0 to II at low frequency (125, 250, and 500 Hz), but not at mid-frequency and high frequency. The respective cutoff hearing thresholds at frequencies of 125, 250, and 500 Hz were 27.5, 32.5, and 40 dBHL, which help predict positive cochlear EH on MR images. By using the sum (27.5 + 32.5 + 40 = 100 dBHL) of cutoff thresholds from three low frequencies as a cutoff value, Group A (80%) showed significantly more ears with sum of low-frequency hearing threshold >100 dBHL than Group B (30%). Conclusion: When sum of three low-frequency (125, 250, and 500 Hz) hearing levels is >100 dBHL, positive cochlear EH may be shown on MR images in definite MD patients. In contrast, those MD patients with sum of three low-frequency hearing levels <100 dBHL, MR imaging should be postponed because resolution of EH may cause negative MR images. Level of evidence: 4.

Evolution of pediatric vertigo/dizziness during the past two decades.

BACKGROUND: Increasing life expectancy and declining birth rate are two key drivers of population aging globally, resulting in a falling population. OBJECTIVE: This study investigated the evolution of pediatric patients with vertigo/dizziness during the past two decades. METHODS: From 2001 to 2010, a total of 17,123 new patients with vertigo/dizziness visited our neurotological clinic. Of them, 472 (2.8%) were children (Group A). In contrast, 260 children (1.3%) out of 20,404 new patients with vertigo/dizziness were experienced during the period 2011-2020 (Group B). All patients underwent an inner ear test battery before diagnosis. RESULTS: The incidence of pediatric vertigo/dizziness in relation to overall neurotological cases significantly decreased from the first decade (2.8%) to the second decade (1.3%). Approximately 80% prevalence of pediatric vertigo/dizziness cases were referred to as vestibular migraine and benign paroxysmal vertigo of childhood regardless of Group A or B. Correlation between annual birth rate (x) and incidence of pediatric vertigo/dizziness cases in relation to overall neurotological cases (y) represented as y = 6.488x - 0.037 via linear regression analysis. CONCLUSION: The evolution of pediatric vertigo/dizziness revealed decreased incidence from 2.8% (2001-2010) to 1.3% (2011-2020), which may be related to the declined annual birth rate from 11.7‰ (2001) to 7.0‰ (2020).

Comparison of the Wii Balance Board System and Foam Posturography System in Assessing Postural Balance.

OBJECTIVE: Falls are a major cause of disability and mortality in the elderly. Postural balance is associated with falls and can be evaluated by posturography. However, conventional posturography is costly and requires a sufficiently large space to perform. Hence, this study developed a portable system to meet the requirement of field studies, and investigated its reliability and validity. DESIGN: A custom-written software application was developed to link a computer to the Nintendo Wii balance board (WBB) and the center of pressure was acquired, which was then compared with that obtained from commercially available foam posturography (FP). Forty younger adults including 20 patients with peripheral vestibular disorders as well as 20 healthy controls, and 50 older patients with peripheral vestibular disorders were enrolled. All subjects underwent postural balance testing using the WBB system (WBSS) and FP system (FPS) in a randomized order. RESULTS: For the intersystem reliability, although the WBSS obtained a significantly smaller mean sway area than the FPS, both systems revealed adequate to excellent reliability with an intraclass correlation coefficient (ICC) of 0.67 to 0.87. The WBBS showed adequate to excellent test-retest reliability (ICC: 0.53 to 0.88). For the validity, the respective cutoff sway areas were 1.03 and 3.09 cm 2 under conditions C and D via the WBBS for discriminating the fallers from nonfallers. CONCLUSION: The WBBS yielded adequate to excellent reliability and validity for accessing postural balance, and had good performance in discriminating the fallers from nonfallers. The WBBS has advantages over the commercial FPS of low cost, easy portability, programmability, and may be better-suited to mass detection and research programs. Most importantly, this WBBS can be performed outside the hospital for testing postural balance, especially in the elderly.

Galvanic vestibular-evoked myogenic potentials in evaluating damaged sites of vestibular neuritis.

Objectives: To test the possibility of pure otolithic organ deficits and validate the histopathological evidence of retrovestibular neural impairment in vestibular neuritis (VN), the authors adopted a topographic survey combining cervical vestibular-evoked myogenic potential (cVEMP) and ocular vestibular-evoked myogenic potential (oVEMP) using various stimulation modes and caloric tests. Methods: Forty patients with VN were enrolled in this study. All patients underwent pure tone audiometry, acoustic cVEMP, galvanic cVEMP, vibratory oVEMP, galvanic oVEMP, and caloric tests. Different combinations of vestibular tests were further compared and analyzed. Results: According to vestibular test results in affected VN ears, the proportion (10%) of pure saccular dysfunction was significantly less than that (52.5%) of saccular nerve deficit. The proportion (2.5%) of pure utricular dysfunction was significantly less than that (37.5%) of utricular nerve deficit. The percentage (82.5%) of VN involving the ampullar vestibulo-ocular reflex (VOR) pathway was significantly higher than that (40%) involving the utriculo-ocular reflex (UOR) pathway. The superior, inferior, and total VN percentages were 37.5%, 17.5%, and 45%, respectively. The proportion of inferior VN was significantly less than that of VN involving the superior vestibular nerve. Conclusion: There were significantly fewer cases of pure otolithic organ dysfunction than vestibular nerve involvement in VN patients. The damage to the ampullar VOR pathway was more significant than that to the UOR pathway, and both pathways might be independent of each other. In addition, the incidence of isolated inferior VN was significantly less than that of VN involving the superior vestibular nerve. Level of Evidence: Level 3.

Predicting secondary endolymphatic hydrops in patients with noise-induced hearing loss.

BACKGROUND: Long-term noise exposure may damage the cochlea and endolymph resorption system, which induces episodic vertigo and/or fluctuating hearing loss in later years. OBJECTIVE: This study adopted clinical symptoms, inner ear test battery, and/or magnetic resonance (MR) imaging to evaluate development of secondary endolymphatic hydrops (EH) in patients with noise-induced hearing loss (NIHL). METHODS: Forty NIHL patients with secondary EH were assigned to Group A. Another 40 age-and sex-matched NIHL patients without EH were assigned to Group B. All patients underwent an inner ear test battery. MR imaging was performed when diagnosis of EH was equivocal via above testing. RESULTS: Group A had significantly higher mean hearing levels (MHLs) than Group B at 1000, 2000, 4000, and 8000 Hz. Both groups displayed a significantly declining sequence of abnormality rates of the inner ear test battery. Under receiver operating characteristic (ROC) curve analysis, the cutoff threshold at 4 kHz for predicting the presence of secondary EH in NIHL patients was 52 dBHL, with a sensitivity of 62% and a specificity of 69%. CONCLUSIONS: NIHL patients revealing a typical 4 kHz dip-type audiogram with dip threshold >52 dBHL may predict development of secondary EH. A longitudinal follow-up coupled with MR imaging is required for confirmation.

Radiological and functional assessment in patients with lumbar spinal stenosis.

BACKGROUND: Although patients with lumbar spinal stenosis (LSS) may have impaired postural control, current diagnosis of LSS depends mainly on clinical manifestation and radiological assessment, while functional assessment of postural balance remains less investigated. This study thus correlated radiological assessment via MR imaging with functional assessment using foam posturography in LSS patients. METHODS: Forty-seven LSS patients aged 50-85 years were enrolled. All patients received subjective outcome measures first, followed by plain radiography of whole spine and lumbosacral spine, MR imaging, and foam posturography under four conditions. Then, these results were analyzed using stepwise multiple regression analysis. Another 47 age- and sex-matched healthy controls also underwent foam posturography for comparison. RESULTS: The LSS group revealed significant increases in the sway area of foam posturography than the control group regardless of various conditions. Advanced age, poor walking endurance, and neural compression at the L2/3 level on MR images were significantly correlated with the characteristic parameters of foam posturography (p < 0.05). In contrast, subjectively reported pain and plain radiography did not correlate with posturographic results (p > 0.05). CONCLUSIONS: Patients with LSS who exhibit less severe symptoms do not ensure normal postural balance. Functional assessment (foam posturography) on postural balance significantly correlated with radiological assessment (MR imaging) in LSS patients. The use of foam posturography may help assess postural control in LSS patients. It takes a short time and costs less, and would be practical to make this a routine examination in LSS patients.

Assessing the cervico-ocular reflex system via modifying the ocular vestibular-evoked myogenic potential test.

PURPOSE: The aim of this study was to devise a novel test for assessing the cervico-ocular reflex (COR) system via head vibration (termed h-COR) or neck vibration (termed n-COR) method. MATERIALS AND METHODS: Thirteen patients with complete loss of bilateral vestibulo-ocular reflex (VOR) showing oscillopsia were assigned to Group A, while 13 patients with bilateral VOR loss but no oscillopsia were Group B. Another 13 healthy elderly served as a control. The COR test was performed via modifying the ocular vestibular-evoked myogenic potential (oVEMP) test by tapping at the forehead with head rotation (h-COR) or at mid-dorsal neck with head straight (n-COR). RESULTS: Both h-COR and n-COR tests displayed similar cI-cII waveforms. None of the Group A or healthy elderly showed present h-COR, while 8% of Group A and 31% of the healthy elderly revealed present n-COR. In contrast, present h-COR and n-COR were elicited in 85 and 77% of Group B, respectively. Restated, significantly higher response rate of COR in Group B (without oscillopsia) than Group A (with oscillopsia) indicates that present COR is related to the alleviation of oscillopsia. CONCLUSIONS: Head vibration method (h-COR test) is superior to neck vibration method (n-COR test) for assessing the COR system.

A model study of resonance effect on ocular vestibular-evoked myogenic potential.

BACKGROUND/PURPOSE: This study measured the acceleration magnitude using a dummy model filled with various air-material ratios to elucidate the mechanism of resonance effect on ocular vestibular-evoked myogenic potential (oVEMP). METHODS: With the percentages of air volume altered by filling various materials (water, glycerol, or ethanol) in an acrylic-made hollow spherical model, a minishaker was utilized to deliver vibration stimuli to the model. Then, acceleration magnitude of each model was measured. RESULTS: Since the air was most occupied at the upper part of the model (z-axis), acceleration magnitude along the z-axis was selected for comparison. An increasing trend of the z-axis acceleration magnitude ranging 0.110-0.759 g was identified in air-water model with air volume percentage ranged 40-100%. On the other hand, a significant increasing trend of acceleration magnitude along the z-axis (0.157-0.759 g) was noted in air-glycerol model with 80-100% of air volume. While in air-ethanol model, a significant increasing trend in acceleration magnitude along the z-axis ranged 0.121-0.759 g correlating with 40-100% of air volume. CONCLUSION: The mechanism for eliciting oVEMP is via the first-order bone vibration coupled with the second-order resonance effect. Both percentage of air volume (i.e. frontal sinus) and density of filling media (i.e. skull property) may contribute to the resonance effect, which then increases the acceleration magnitude so as to enhance the elicitation of oVEMP.

Effect of Video Games on the Otolithic Reflex System.

BACKGROUND: Video gaming (VG) has since the 1980s become increasingly ubiquitous entertainment among the adolescents and young adults. Many young people expe-rienced dizzy spells, but not vertiginous episodes, after playing VG. OBJECTIVES: This study performed ocular vestibular-evoked myogenic potential (oVEMP) and cervical VEMP (cVEMP) tests in subjects before and after engaging on VG to investigate the effect of VG on the otolithic reflex system. METHODS: Twenty subjects who frequently played VG (>3 days per week) for more than 10 years were assigned to the long-term group. Another 20 subjects with engaging on VG <3 days per week or <10 years were assigned to the short-term group. Each subject underwent baseline oVEMP and cVEMP tests first, followed by playing VG for 1 h. Then, all subjects underwent the same paradigm. The "VG-year" is defined as frequency of VG playing within 1 week (day/week) multiplied by total length of VG engagement (year). RESULTS: Engagement on VG rarely affected the oVEMP responses for either short- or long-term players. In contrast, the response rates of cVEMP significantly declined from pre-VG period (80%) to post-VG period (58%) in the short-term group, but not in the long-term group. The cutoff value for predicting absent cVEMP in VG engagement is 21 VG-year. CONCLUSION: Short-term engagement on VG may result in temporary cVEMP loss, while permanent cVEMP loss could be identified in long-term VG players. The cutoff value for predicting absent cVEMP in VG engagement is 21 VG-year, indicating that damage to the sacculo-collic reflex system could be anticipated in a subject who has played VG at least 1 h per session, 7 days weekly for 3 years.