Comparison of Gait Parameters during Forward Walking under Different Visual Conditions Using Inertial Motion Sensors

Purpose@#Gait evaluation in patients with dizziness is essential during both initial evaluation and vestibular rehabilitation. Inertial measurement unit (IMU)-based gait analysis systems are clinically applicable in patients with dizziness. Since dizzy patients can utilize visual inputs to compensate for vestibular deficits, it is more difficult for them to walk with their eyes closed (EC). In this study, we compared gait characteristics during forward walking with both eyes open (EO) and EC between healthy subjects and dizzy patients. @*Materials and Methods@#Forty-nine healthy controls (mean age 37.18±10.71 years) and 23 patients with dizziness (mean age 49.25± 15.16 years) were subjected to vestibular and gait analyses. Medical histories, physical examinations, and vestibular function tests ruled out possible vestibular deficits in the controls. Subjects were instructed to walk at a comfortable pace for 10 m under two conditions (EO or EC). Spatiotemporal parameters, kinematics, and simulated kinetics of each gait recording were recorded using a shoe-type IMU system and analyzed. @*Results@#Although gait speeds were slower, stride lengths were smaller, and double support times were increased under the EC, compared to the EO condition, in both healthy subjects and dizzy patients, the difference was more prominent in dizzy patients.Phase coordination index values did not differ significantly in either group. Gait asymmetry (GA) increased significantly under the EC condition, compared to the EO condition, in dizzy patients. @*Conclusion@#GA during forward walking was greater in dizzy patients under an EC condition than under an EO condition.

Limitation of Conventional Audiometry in Identifying Hidden Hearing Loss in Acute Noise Exposure

Purpose@#The concept of hidden hearing loss can explain the discrepancy between a listener’s perception of hearing ability and hearing evaluation using pure tone audiograms. This study investigated the utility of the suprathreshold auditory brainstem response (ABR) for the evaluation of hidden hearing loss in noise-exposed ear with normal audiograms. @*Materials and Methods@#A total of 15 patients (24 ears) with normal auditory thresholds and normal distortion product otoacoustic emissions were included in a retrospective analysis of medical records of 80 patients presenting with histories of acute noise exposure. The control group included 12 subjects (24 ears) with normal audiograms and no history of noise exposure. Pure tone audiometry and suprathreshold ABR testing at 90 dB peSPL were performed. The amplitudes and latencies of ABR waves I and V were compared between the noise-exposed and control groups. @*Results@#We found no significant difference in the wave I or V amplitude, or the wave I/V ratio, between the two groups. The latencies of ABR wave I, V, and I–V interpeak interval were compared, and no significant intergroup difference was observed. @*Conclusion@#The results suggest that either hidden hearing loss may not be significant in this cohort of patients with acute noise exposure history, or the possible damage by noise exposure is not reflected in the ABRs. Further studies are needed to inquire about the role of ABR in identification of hidden hearing loss.

Limitation of Conventional Audiometry in Identifying Hidden Hearing Loss in Acute Noise Exposure

Purpose@#The concept of hidden hearing loss can explain the discrepancy between a listener’s perception of hearing ability and hearing evaluation using pure tone audiograms. This study investigated the utility of the suprathreshold auditory brainstem response (ABR) for the evaluation of hidden hearing loss in noise-exposed ear with normal audiograms. @*Materials and Methods@#A total of 15 patients (24 ears) with normal auditory thresholds and normal distortion product otoacoustic emissions were included in a retrospective analysis of medical records of 80 patients presenting with histories of acute noise exposure. The control group included 12 subjects (24 ears) with normal audiograms and no history of noise exposure. Pure tone audiometry and suprathreshold ABR testing at 90 dB peSPL were performed. The amplitudes and latencies of ABR waves I and V were compared between the noise-exposed and control groups. @*Results@#We found no significant difference in the wave I or V amplitude, or the wave I/V ratio, between the two groups. The latencies of ABR wave I, V, and I–V interpeak interval were compared, and no significant intergroup difference was observed. @*Conclusion@#The results suggest that either hidden hearing loss may not be significant in this cohort of patients with acute noise exposure history, or the possible damage by noise exposure is not reflected in the ABRs. Further studies are needed to inquire about the role of ABR in identification of hidden hearing loss.

Audiologic Status of Children with Confirmed Cytomegalovirus Infection: a Case Series

Background@#Congenital cytomegalovirus (CMV) infection is the most common non-genetic cause of sensorineural hearing loss (SHNL) in children. Only about 10% to 15% of children with congenital CMV are symptomatic, and most are not diagnosed at birth. About 7% to 15% of clinically asymptomatic patients may develop later complications, including SNHL, which is the most common sequela in clinically asymptomatic patients. In this study, hearing status was investigated in children with confirmed CMV infection and neonatal hearing screening (NHS) histories were reviewed to explore hearing loss caused by CMV. @*Methods@#The medical records of 58 children who were diagnosed with confirmed CMV infection were reviewed for clinical symptoms and signs of CMV infection. Hearing status was evaluated with age-appropriate audiological test batteries. @*Results@#A total of 58 children (M:F = 32:26 patients; age at study: mean, 5.62 years, range, 1-10 years) were diagnosed serologically with CMV infection (14 patients, 21.1%), or diagnosed via PCR of serum (5, 7.9%) and/or PCR from urine (19, 26.8%). Hearing loss was confirmed in 11 children (19.0%), being bilateral in 6 (54.5%), and unilateral in 5 (45.5%). Note that 7 of 17 ears with hearing loss passed NHS and were diagnosed only after re-evaluation when CMV infection was identified. @*Conclusion@#Hearing loss is a serious complication of CMV infection in children. Our results highlight the importance of timely audiological evaluation in children with clinically symptomatic CMV infection even if they pass NHS.

Role of Emotional Distress in Prolongation of Dizziness: A Cross-Sectional Study

BACKGROUND AND OBJECTIVES: Dizziness is a common condition in outpatient clinics. Comorbid conditions such as anxiety and/or depression often complicate a patient’s ability to cope with dizziness. The purpose of the present study was to explore the extent of psychiatric distress using the Hospital Anxiety and Depression Scale (HADS) and to compare the results with the subjective severity of dizziness. SUBJECTS AND METHODS: The cross-sectional study included a total of 456 consecutive patients presenting with acute (n=327) and chronic (n=127) dizziness symptoms. The HADS was used to estimate emotional distress and compare between patients with acute and chronic dizziness symptoms. Also, we calculated correlations between subjective dizziness handicap scores and emotional distress using the total and subscale scores of the Dizziness Handicap Inventory (DHI), Disability Scale (DS), and HADS. RESULTS: The HADS total and subscale scores were significantly increased in patients with chronic dizziness (p<0.01) compared with those with acute symptoms. In patients with symptoms of both acute and chronic dizziness, moderate correlations were evident between the DHI and HADS total scores. When we compared DHI subscale scores with the HADS scores, the emotional DHI subscale scores correlated more highly with the HADS total scores and the scores on the anxiety and depression subscales, than did the functional or physical DHI subscale scores. CONCLUSIONS: Increased levels of distress measured using the HADS in patients with chronic symptoms suggest that emotional status of the patients may contribute to prolongation of dizziness symptoms from the acute phase.

Prognostic Factors Affecting Surgical Outcomes in Squamous Cell Carcinoma of External Auditory Canal

OBJECTIVES: Carcinomas of the external auditory canal (EAC) are rare, and management remains challenging. Previous studies seeking prognostic factors for EAC cancers included cancers other than carcinomas. In this study, we analyzed the treatment outcomes of, prognostic factors for, and survival rates associated with specifically squamous cell carcinoma (SCC) of the EAC. METHODS: A retrospective review of 26 consecutive patients diagnosed with SCCs of the EAC in a 10-year period was performed in terms of clinical presentation, stage, choice of surgical procedure, and adjunct therapy. Overall survival (OS) and recurrence-free survival (RFS) were calculated and univariate analysis of prognostic factors was performed. RESULTS: The median age of the 26 patients with SCCs of the EAC was 63 years (range, 40 to 72 years), and 16 males and 10 females were included. According to the modified University of Pittsburgh staging system, the T stages were T1 in 11, T2 in six, T3 in four, and T4 in five cases. The surgical procedures employed were wide excision in three cases, lateral temporal bone resection (LTBR) in 17, and extended LTBR in four, and subtotal temporal bone resection in two. Two patients underwent neoadjuvant chemotherapy, and two underwent adjuvant chemotherapy. One patient received preoperative radiation therapy, and eleven received postoperative radiation therapy. Of the possibly prognostic factors examined, advanced preoperative T stage and advanced overall stage were significant predictors of RFS, but not of OS. CONCLUSION: The advanced T stage and overall stage were associated with decreased survival after surgical treatment in patients with SCC of the EAC, highlighting the importance of clinical vigilance and early detection.

Relationship of Vertigo and Postural Instability in Patients With Vestibular Schwannoma

OBJECTIVES: Growth of vestibular schwannomas (VS) causes progressive vestibular symptoms and postural instability. Since the tumor grows slowly, compensation of decaying vestibular input may decrease subjective symptoms of dizziness. This study aims to estimate the relationship of subjective vestibular symptoms and objective postural instability in patients with VS. METHODS: A retrospective review of 18 patients newly diagnosed with VS and with subjective vertigo symptoms was performed. The results of vestibular function tests including the sensory organization test (SOT) using computerized dynamic posturography, caloric test, and self-report measures of subjective dizziness handicap (Dizziness Handicap Inventory) and visual analogue scale were compared according to the onset of vertigo symptoms. RESULTS: In VS patients, SOT showed decreased equilibrium score for all vestibular function related conditions, condition (C) 5 and 6, and composite (COMP) score. COMP scores were not correlated with visual analogue scale or Dizziness Handicap Inventory scores. Acute onset group included six patients and insidious onset group, 12 patients. Equilibrium scores for C5 and C6, and COMP scores were lower for insidious onset group, but the difference was not statistically significant. CONCLUSION: Our findings confirmed postural instability is prevalent in VS patients. SOT parameters did not differ significantly between acute onset and insidious onset groups, but increased tumor size and canal weakness were noted in the insidious onset group. Clinicians should consider that postural instability is likely present even in patients who do not complain of acute vertigo, and appropriate counseling should be discussed with the patients.

Comparison of Acceptable Noise Levels Using Korean and Non-Semantic Speech Signals in Normal Hearing Subjects / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The acceptable noise level (ANL) test measures the maximum noise level that a subject can tolerate while following speech. Given the limited investigation of ANL across different languages, this study aimed to compare ANLs using both Korean semantic speech and non-semantic speech signals (reversed Korean speech and international speech test signal, ISTS) in normal-hearing subjects. SUBJECTS AND METHOD: Twenty-five subjects with normal hearing (9 males, 16 females, with the mean age of 28.5±3.15 years) were included in the study. ANLs were obtained using three speech materials (Korean speech, reversed Korean speech, and ISTS) as the target speech material and an eight-talker babble noise as the competing background noise. RESULTS: Generally, the inter-subject variability was large. The ANLs did not differ statistically regardless of the type of speech signal. CONCLUSION: The ANLs seemed to be unaffected by the meaningfulness or semantic contents of the target speech, at least in normal-hearing adults. Thus, non-meaningful speech signals or non-semantic material can be considered as the target signal for the implementation of ANL test.

Assessment of Attentional Demand in Patients with Dizziness Using Dual Task Test / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Even patients with compensated peripheral vestibular dysfunction may report a sense of disequilibrium during daily activities, which often fail conventional vestibular function tests as attentional demand required for postural control may increase in these patients. The study aims to assess the feasibility of dual task test using concurrent cognitive tasks in a modified clinical test of sensory interaction on balance (mCTSIB) to measure increased attentional demand for posture control. SUBJECTS AND METHOD: Nineteen patients suspected with chronic dizziness were recruited by history reviews and physical examinations. Data for center of pressure (COP) variability and mean velocity during mCTSIB on a force long plate were analyzed, and time taken to react to the auditory stimuli were used to measure the attentional demand required for adequate postural control during platform perturbation. RESULTS: The mean COP range and velocity during mCTSIB were comparable between single and dual task conditions in patients with dizziness. Reaction time (RT) to auditory stimulus of 1 kHz pure tone in patients with chronic dizziness was also comparable to normal subjects. Interestingly, there was a tendency for increased RT in patients with documented caloric weakness, suggesting that attentional demand is increased in these patients. CONCLUSION: RT of dual task tests using auditory stimuli during mCTSIB may provide additional information about increased attentional demand for postural control in patients with vestibular dysfunction.

Long-Term Outcomes of Acute Low-Tone Hearing Loss

BACKGROUND AND OBJECTIVES: Although acute low-tone hearing loss has been associated with cochlear hydrops or early stage Meniere's disease, its prognosis in the short-term has been reported to be better than sudden hearing loss. However, recurrence of hearing loss and possible progression to Meniere's disease remain important concerns in the clinical setting. This study aims to investigate the long-term audiological outcomes of acute low-tone hearing loss. SUBJECTS AND METHODS: A retrospective review of patients presenting with a first attack of acute low-tone hearing loss was performed. Of the 77 patients, 33 were followed up for more than 3 months. Progression, recovery of hearing loss and recurrence of hearing loss were examined. Also, correlation between long-term outcomes and associated clinical factors were analyzed. RESULTS: Twenty-five patients (75.7%) had complete hearing recovery, five patients (15.1%) had partial recovery, two patients (6.0%) had no recovery, and one patient (3.0%) had progression of hearing loss 1 month after initial treatment. Thirty-three patients were followed up for more than 3 months (mean 22 months, range 3-79 months). Recurrences of acute low-tone hearing loss were observed in five patients (15.2%). All of the recurrences occurred during the first 12 months of follow-up. Long-term prognosis correlated with the initial therapy results (R2=0.693). CONCLUSIONS: Recurrences of hearing loss were documented in five patients (15.2%), and all of these cases occurred within one year of the first attack. Audiological outcomes after initial therapy may predict the recurrence of acute low-tone hearing loss.

A Case of Incus Vibroplasty: Postoperative Changes in Residual Hearing

In patients with mild to severe hearing loss, conventional hearing aids offer limited benefits and several problems with feedback and cosmesis. Middle ear implants are a feasible option for patients with moderate to severe hearing loss who are unable to achieve adequate benefit from or cannot tolerate hearing aids for various reasons. Here we present a case of middle ear implant surgery using Vibrant Soundbridge with incus vibroplasty technique, and describe the hearing changes during postoperative follow-up.

Multicenter Study on the Clinician's Diagnostic and Therapeutic Approaches for Benign Paroxysmal Positional Vertigo in Korea / 대한평형의학회지

BACKGROUND AND OBJECTIVES: It is necessary to establish the most efficient diagnostic and therapeutic method for benign paroxysmal positional vertigo (BPPV), which is appropriate for Korean healthcare system. We aimed to evaluate current state of Korean clinician's diagnostic and therapeutic approaches for BPPV. MATERIALS AND METHODS: A 16-item survey was emailed to the members of dizziness department of Otology Research Interest Group in the Korean Otologic Society (n=68). 43 were returned and analyzed. RESULTS: All respondents (100%) used Dix-Hallpike test as a diagnostic tool for vertical canal-BPPV. Supine roll test was used for diagnosing lateral canal BPPV in nearly all the respondents (97.7%). Epley maneuver was chosen as otolith repositioning maneuver (ORM) for posterior canal BPPV in all respondents and barbecue rotation (BBQ) was used for treating lateral canal BPPV with geotropic nystagmus in 95.3% of respondents. Extreme variation was noted for therapeutic approach of lateral canal BPPV with ageotropic nystagmus BBQ, with 4 kinds of ORM and adjunctive measures to liberate otolith from cupula, while BBQ was again the most commonly used ORM (76.7%). CONCLUSION: The development of practical and efficient ORM for lateral canal BPPV with ageotropic nystagmus is necessary.

Radiologic Characteristics in a Case of Facial Nerve with Multisegment Involvement / 대한이비인후과학회지

A 47-year-old female patient presented with an acute onset of facial palsy and otitis media on the left side. Temporal bone CT scans revealed an irregularly shaped lesion in the middle ear cavity extending into the mastoid air cells. MRI images confirmed intra- and extra-temporal involvement of the facial nerve schwannoma. The correlation of distinct imaging findings of the facial nerve schwannoma along the course of the facial nerve and anatomical features of the temporal bone is discussed.

Recent Advances in Research of Cochlear Tonotopicity / 대한이비인후과학회지

The ability of to discern distinct sound frequencies is attributed to frequency specificity in various locations in the auditory pathway. The cochlear duct is tonotopically organized along its longitudinal axis so that the basal turn responds to high frequency and the apical turn to low frequency sounds. Since the cochlear duct is comprised of heterogeneous components including sensory hair cells, neurons and other cellular and acellular components, integration of their diverse features is essential for establishment of tonotopicity. Recent studies aim to investigate the molecular mechanisms responsible for the cochlear tonotopicity.

Nasal Colonization of Methicillin-Resistant Staphylococcus aureus in Patients with Chronic Suppurative Otitis Media

BACKGROUND AND OBJECTIVES: Methicillin-resistant Staphylococcus aureus (MRSA) is one of major pathogens in patients with chronic suppurative otitis media (CSOM). In addition to intrinsic MRSA infection of the mastoid air cell system, nasal colonization of MRSA, a known predictor of postoperative surgical site infection, may pose increased risk of postoperative complications. The purpose of this study is to describe microbiology of preoperative nasal swab screening and localized middle ear specimens in patients undergoing otologic surgeries. SUBJECTS AND METHODS: Forty-nine consecutive patients with CSOM who underwent middle ear surgery were included. Preoperative nasal swabs for MRSA, and preoperative and intraoperative middle ear swabs were collected and compared for pathogens. RESULTS: Preoperative nasal swab screening confirmed MRSA colonization in 3/49 patients (6.1%) and methicillin-resistant coagulase-negative Staphylococcus (MRCNS) in 9/49 patients (18.4%). Correlation with preoperative culture results and nasal swab screening results were compatible in 2/4 patients with positive nasal swab for MRSA and 1/9 patients with positive nasal swab for MRCNS. Postoperative conversion to MRSA was observed in 3 patients. CONCLUSIONS: The rate of nasal MRSA colonization among patients with CSOM was higher than among the general community. Preoperative MRSA colonization was associated with MRSA from middle ear specimens. Further studies are warranted to investigate the possible benefit of preoperative treatment of MRSA colonized patients undergoing middle ear surgeries.

Treatment Strategy for Sudden Sensorineural Hearing Loss / 대한이비인후과학회지

Sudden sensorineural hearing loss is an emergent disease in otologic field. Because the etiology and pathological mechanism were not proven yet, treatment protocol was not established. Therefore, medications, duration, and dosage were different from each institute. In this review, authors collected and analyzed articles on sudden sensorineural hearing loss published during recent 11 years. From those, we described the recommendations on the criteria and method of diagnosis, tools for treatment and their results, and guideline for reporting results and follow up.

Evaluation of Transient Evoked Otoacoustic Emission in the Newborn Hearing Screening Program in Neonatal Intensive Care Unit

BACKGROUND AND OBJECTIVES: Newborn Hearing Screening (NHS) program aims to identify babies at risk of hearing loss and provide appropriate rehabilitation within the crucial period for language development. The risk of hearing loss in increased in babies discharged from neonatal intensive care unit (NICU) compared to wellbaby nursery. Transient evoked otoacoustic emission (TEOAE) or automated auditory brainstem response tests are utilized. The purpose of this study is to assess the outcome of NHS using TEOAE as initial evaluation method in NICU graduates. SUBJECTS AND METHODS: TEOAE was performed as initial screening method for NHS in NICU neonates born between February 2010 and November 2011. Babies referred from TEOAE were reevaluated with repeated TEOAE or auditory brainstem response. Referral rates were estimated and quality indicators for screening (Joint Committee on Infant Hearing position statement, 2007) were evaluated. RESULTS: Among 149 neonates graduated from NICU, 50 (33.6%) babies failed initial TEOAE ('refer'). A second stage TEOAE testing was performed in 41 (82.0%) of these babies: 35 (85.4%) passed and 6 (14.6%) were referred for diagnostic testing. From 2-stage TEOAE screening program, 6 neonates were referred for diagnostic audiological evaluation: sensorineural hearing loss was identified in 2 babies and 3 babies were lost to follow up. Quality indicators for screening were as follows: 1) 94.0% of all newborn infants admitted to NICU completed screening by 1 month of age, and 2) 4.0% of all newborn infants who fail initial screening and fail any subsequent rescreening before comprehensive audiological evaluation. CONCLUSIONS: Timely and adequate screening of hearing loss is prerequisite for accurate diagnosis and appropriate rehabilitation in infants especially from NICU. Further refinement of the current NHS with additional reliable screening technology is required for more stable and successful screening program.

Evaluation of Transient Evoked Otoacoustic Emission in the Newborn Hearing Screening Program in Neonatal Intensive Care Unit

BACKGROUND AND OBJECTIVES: Newborn Hearing Screening (NHS) program aims to identify babies at risk of hearing loss and provide appropriate rehabilitation within the crucial period for language development. The risk of hearing loss in increased in babies discharged from neonatal intensive care unit (NICU) compared to wellbaby nursery. Transient evoked otoacoustic emission (TEOAE) or automated auditory brainstem response tests are utilized. The purpose of this study is to assess the outcome of NHS using TEOAE as initial evaluation method in NICU graduates. SUBJECTS AND METHODS: TEOAE was performed as initial screening method for NHS in NICU neonates born between February 2010 and November 2011. Babies referred from TEOAE were reevaluated with repeated TEOAE or auditory brainstem response. Referral rates were estimated and quality indicators for screening (Joint Committee on Infant Hearing position statement, 2007) were evaluated. RESULTS: Among 149 neonates graduated from NICU, 50 (33.6%) babies failed initial TEOAE ('refer'). A second stage TEOAE testing was performed in 41 (82.0%) of these babies: 35 (85.4%) passed and 6 (14.6%) were referred for diagnostic testing. From 2-stage TEOAE screening program, 6 neonates were referred for diagnostic audiological evaluation: sensorineural hearing loss was identified in 2 babies and 3 babies were lost to follow up. Quality indicators for screening were as follows: 1) 94.0% of all newborn infants admitted to NICU completed screening by 1 month of age, and 2) 4.0% of all newborn infants who fail initial screening and fail any subsequent rescreening before comprehensive audiological evaluation. CONCLUSIONS: Timely and adequate screening of hearing loss is prerequisite for accurate diagnosis and appropriate rehabilitation in infants especially from NICU. Further refinement of the current NHS with additional reliable screening technology is required for more stable and successful screening program.

Uridine-5'-Triphosphate Stimulates Chloride Secretion via Cystic Fibrosis Transmembrane Conductance Regulator and Ca2+-Activated Chloride Channels in Cultured Human Middle Ear Epithelial Cells / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Nucleotide binding to purinergic P2Y receptors contributes to the regulation of fluid and ion transport in the middle ear epithelial cells. Here, we investigated the regulatory mechanism of the P2Y2 receptor agonist, uridine-5'-triphosphate (UTP), on Cl- transport in cultured normal human middle ear epithelial (NHMEE) cells. MATERIALS AND METHOD: Electrophysiological measurements were performed in monolayers of cultured NHMEE cells. Short circuit currents (Isc) were measured from the cells mounted in Ussing chambers under various conditions. RESULTS: Apical addition of UTP in presence of amiloride evoked a transient rise and a sustained response in Isc due to Cl- efflux. Application of different Cl- channel blockers to the apical side of the cells significantly decreased UTP-induced Isc. Niflumic acid (NFA), a known blocker of Ca(2+)-activated chloride channels (CACC), and CFTRinh172, a selective inhibitor of cystic fibrosis transmembrane conductance regulator (CFTR), partially inhibited the UTP-induced Cl- secretion, respectively. CONCLUSION: Cl- transport across the airway epithelia plays a predominant role in regulating airway hydration. In this study, UTP is shown to increase both CACC and CFTR-dependent Cl- secretion in NHMEE cells, suggesting their role in fluid and ion transport in the middle ear epithelium.

Evaluation of Trigeminal Nerve Involvement Using Blink Reflex Test in Bell's Palsy

BACKGROUND AND OBJECTIVES: Facial nerve dysfunction in Bell's palsy is evaluated using various parameters including physical examination and electrophysiological studies. Associated symptoms of facial numbness or paresthesia are reported by some patients with Bell's palsy. The aim of this study was to investigate trigeminal nerve involvement in Bell's palsy using blink reflex test. SUBJECTS AND METHODS: Facial nerve and trigeminal nerve functions were assessed using House-Brackmann (HB) grading system, electroneuronography (ENoG) and blink reflex tests in 28 patients diagnosed as Bell's palsy. RESULTS: HB grades correlated with degeneration ratio from ENoG (p=0.002, chi-square test). The ipsilateral R1 reponse of the blink reflex was absent or abnormal in 27/28 patients (96.4%), and ipsilateral R2 response was absent or abnormal in 26/28 patients (92.8%). Contralateral R2 was abnormal in 5/28 patients (17.8%), suggesting involvement of trigeminal nerve in a portion of patients. The results of blink reflex test showed no significant correlation to the outcome of facial nerve function (HB grade) in Bell's palsy patients. CONCLUSIONS: Blink reflex test provides information about trigeminal and facial nerve functions in addition to ENoG results. Our study suggests that subclinical involvement of trigeminal nerve may accompany facial nerve dysfunction in Bell's palsy.