Somatosensory shift of postural control in dizzy patients

Conclusions: Postural control is dependent on the visual system in normal conditions. Shift from visual to somatosensory dependence in dizzy patients suggests that utilizing the stable visual references is recommended for the rehabilitation of dizzy patients. Objectives: To investigate which of the visual or somatosensory system is mainly used for substitution of the impaired spatial orientation in dizzy patients. Methods: We recruited 189 consecutive patients with or without dizziness and vestibular dysfunction. Dizzy patients were divided into three groups: acute, episodic, and chronic dizziness. Vestibular function was assessed by caloric test, traditional head impulse test, and head shaking nystagmus. Visual or somatosensory dependence of spatial orientation was assessed by posturography on a solid surface or on foam in eyes open or closed condition. The foam ratio (posturography with/without foam) when eyes were closed was indicative of somatosensory dependence of postural control, whereas the Romberg ratio on foam showed visual dependence. (Romberg ratio on foam)/(foam ratio with eyes closed) was calculated and used as an index of the visual/somatosensory dependence of postural control. Results: The visual/somatosensory ratio of postural control was significantly lower in dizzy patients as well as patients with vestibular dysfunction, however, no differences were found between acute, episodic, and chronic dizziness.     

Computerized dynamic posturography and seasickness susceptibility

OBJECTIVE/HYPOTHESIS: The neural mismatch theory emphasizes the role of conflicting multimodal sensory interactions in producing both motion sickness and the rearrangement process that finally leads to habituation to the adverse motion conditions. If this theory is, indeed, correct, the patterns of the response to the integrated signal from simultaneous multisensory stimulation, characterized by unusual relationships between the senses responsible for spatial orientation, should differ according to motion sickness susceptibility. Computerized dynamic posturography (CDP) provides the opportunity to simultaneously change the interactions between visual, somatosensory, and vestibular inputs, thus giving an indication of the relative importance of these senses in maintaining balance. The objective was to investigate balance strategies in naval crew members with differing susceptibility to sea conditions using CDP. STUDY DESIGN: Cross-sectional, parallel-group design. METHODS: Twenty subjects susceptible to seasickness (SS) and 20 nonsusceptible subjects (NSS), healthy male volunteers aged 18 to 25, were tested using the EquiTest system (NeuroCom, Inc., Clackamas, OR). RESULTS: The SS group exhibited significantly less stability than the NSS group in condition 5 of the sensory organization test (SOT). The ratio of the SOT scores of conditions 5 to 1 (the vestibular organization pattern) was also found to be significantly lower in the SS group. CONCLUSIONS: The results suggest that SS might be more dependent on somatosensory and visual inputs and less on vestibular inputs for maintenance of balance compared with NSS. Higher susceptibility to seasickness might reflect abnormal weighting of sensory modalities during the integration process. This would result in disruption of the integration process required to maintain balance and a sense of orientation in space in conditions producing conflicting sensory inputs.     

Abstinent chronic alcoholics investigated by dynamic posturography, ocular smooth pursuit and visual suppression

Eleven male chronic alcoholic volunteers aged 44-65 years (mean 57 years) were investigated by dynamic posturography, ocular smooth pursuit and visual suppression of the vestibulo-ocular reflex (VOR). Their drinking time ranged from 8-30 years (mean 20 years) and they had been abstinent for the last 1-20 years (mean 7 years). Ocular smooth pursuit showed abnormalities in 8/11. Abnormalities were found in 5/11 in the visual suppression of the VOR. The results of dynamic posturography tests were compared to an age-matched reference material. Dynamic posturography (EquiTest) comprises a sensory organization (SO) part in which the support surface and visual surround are either stable or referenced to the patient's sway, with eyes open or closed. In the SO part the chronic alcoholics had lower equilibrium scores in all test conditions, and the differences were significant in 4 tests out of 6. In a movement coordination part the platform makes active movements, the latencies to which were significantly prolonged in the 2 larger of the 3 translational amplitudes. Adaptation to repeated tilting of the platform was estimated to be pathological in 4/10, compared to none of the controls. The abnormal pattern found in dynamic posturography correlates well with the pathology in ocular smooth pursuit and visual suppression tests, suggested to be due to alcohol induced cerebellar lesions. It is concluded that dynamic posturography is a valuable test for assessing dysequilibrium in chronic alcoholics, even abstinent.     

Improvement of motor development and postural control following intervention in children with sensorineural hearing loss and vestibular impairment

OBJECTIVE: The purpose of this study was to determine the effect of exercise intervention on the progressive motor development delay and postural control impairments in children with sensorineural hearing loss and concurrent vestibular impairment. METHODS: Twenty-one children with sensorineural hearing loss and vestibular impairment were randomly assigned to two groups (exercise and placebo) matched for age and gross motor development level. Exercise intervention consisted of compensatory training, emphasizing enhancement of visual and somatosensory function, and balance training. Placebo intervention focused on language development activities. Each intervention was administered three times weekly for 12 weeks. Motor development and posturography testing was completed pre- and post-intervention. To examine the mechanisms of change, somatosensory, visual and vestibular functional effectiveness ratios were calculated from posturography stability scores. Children in the placebo group later participated in exercise intervention, and a second post-test completed. Data were analyzed by group, as well as merged once all had received exercise intervention. RESULTS: Post-intervention, motor development scores significantly improved in the exercise, not the placebo group (P=0.004). Although not significant, improvement in posturography scores were evident in the exercise group. Once the post-exercise data from both groups were merged (n=21), improvements in these scores were significant (< or =0.02). The difference from the normative sample was eliminated. CONCLUSIONS: Exercise intervention focused on the enhancement of sensory integrative postural control abilities is effective for the arrest of the progressive motor development delay in children with sensorineural hearing loss and vestibular impairment.     

Patterns of vestibular function following vestibular nerve section.

Bithermal caloric irrigations, low-frequency rotational chair stimulation, and posturography were performed on 20 patients before and after vestibular nerve section. Twelve patients demonstrated acute postoperative spontaneous nystagmus and rotational vestibulo-ocular reflex (VOR) asymmetry. Eight patients demonstrated minimal acute postoperative spontaneous nystagmus and VOR asymmetry. Four patients had suppression of all vestibular function characterized by an absent contralateral caloric response, low VOR gain, and falls on posturography when required to rely solely on vestibular input to maintain posture. Four patients had a severe preoperative vestibular loss and no acute change in vestibular function following surgery. Over time, 5 patients continued to manifest elevated spontaneous nystagmus, 2 patients manifested a persistent rotational VOR asymmetry, and 5 patients exhibited a return of caloric function in the operated ear. It is suggested that multiple clinical factors contributed to the variable vestibular responses demonstrated in this study.     

Anatomical and Physiological Considerations in Vestibular Dysfunction and Compensation

Sensory information from the vestibular, visual, and somatosensory/proprioceptive systems are integrated in the brain in complex ways to produce a final motor output to muscle groups for maintaining gaze, head and body posture, and controlling static and dynamic balance. The balance system is complex, which can make differential diagnosis of dizziness quite challenging. On the other hand, this complex system is organized anatomically in a variety of pathways and some of these pathways have been well studied. The vestibulo-ocular reflex (VOR) is one such pathway. Understanding the anatomy and physiology of the VOR facilitates our understanding of normal and abnormal eye movements and research is advancing our understanding of the plasticity of the vestibular system. This review highlights anatomical and physiological features of the normal vestibular system, applies these concepts to explain some clinical findings in some common peripheral vestibular disorders, and discusses some of the research investigating the anatomical and physiological basis for vestibular compensation.     

Effects of unilateral loss of vestibular function on the vestibulo-ocular reflex and postural control

Long-term recovery from surgically induced unilateral loss of vestibular function was studied in 14 patients. Seven patients underwent surgical extirpation or section of the vestibular nerve, and seven patients underwent labyrinthectomy without vestibular nerve section. The vestibulo-ocular reflex (VOR) and postural control were evaluated preoperatively and monitored for up to 4 years postoperatively with use of pseudorandom rotation (combined sinusoidal frequencies from 0.009 to 1.5 Hz) and moving platform posturography. Immediately following surgery all patients showed minimal reductions in the VOR gain constant, but marked reduction in the time constant, and marked increase in slow eye velocity bias. Bias returned to normal values within about 10 days, but time constants never returned to normal values. Results of standard Romberg tests in these patients were normal throughout the preoperative and postoperative periods. However, all patients showed marked postural control abnormalities in tests of the ability to maintain balance in unusual sensory environments in the immediate postoperative period. Seventy-five percent of the patients eventually recovered normal postural control. Postural control returned to near baseline performance with a time course similar to that of the VOR bias. However, postural control also continued to improve after the recovery of VOR bias was complete.     

Clinical assessment of postural stability following vestibular nerve section

Little is known about the recovery of postural control in patients following acute vestibular loss. This paper reports on the results of moving-platform posturography to assess the recovery of postural stability in 24 patients following vestibular nerve section. Posturography was abnormal prior to surgery in 17% of the patients. Seven days following surgery, 44% of the patients demonstrated vestibular deficit patterns, while 56% of the patients had normal posturography. Posturography was normal in all patients 1 month following surgery. Abnormal posturography was subsequently noted in 21% of the patients between 3 and 20 months following surgery. Each of the patients with abnormal preoperative posturography subsequently demonstrated abnormal late postoperative posturography. These results suggest that perioperative posturography may be useful in the evaluation and counseling of patients considering ablative vestibular surgery.     

动态平衡仪在良性阵发性位置性眩晕患者平衡功能评价及康复治疗中的应用价值

目的 探讨动态平衡仪在良性阵发性位置性眩晕(benign paroxysmal positional vertigo,BPPV)患者平衡功能评价及康复治疗中的应用价值.方法 回顾性分析2007年5月至2008年12月48例后半规管BPPV患者的临床资料.所有患者分别于Epley法复位前后行动静态平衡仪及冷热试验检查,并对结果进行分析比较.对于复位后眼震消失但仍有平衡障碍的患者采用动态平衡仪进行平衡康复训练,3周后再行动态平衡仪检查.结果 48例BPPV患者,Epley法复位前,冷热试验异常12例,占25.O%;静态平衡仪异常16例,占33.3%;动态平衡仪异常34例,占70.8%.经统计分析,动态平衡仪异常率高于冷热试验及静态平衡仪,差异具有统计学意义(χ2值分别为4.84和7.88,P值均＜O.05).Epley法复位治疗后,冷热试验异常7例,静态平衡仪异常4例,动态平衡仪异常8例.复位治疗后动态及静态平衡仪测试结果异常率明显降低,差异具有统计学意义(χ2值分别为24.04和1O.08,P值均＜0.05);而冷热试验结果无明显变化,治疗前后差异无统计学意义(χ2=3.2,P＞0.05).运用动态平衡仪对复位治疗后仍有平衡障碍的8例患者进行平衡康复训练,3周后所有患者平衡不稳感均消失,复查动态平衡仪结果均正常.结论 动态平衡仪可定量分析姿势平衡状态,有助于全面评价BPPV患者的平衡功能;BPPV患者多伴有平衡功能的降低,Epley法复位治疗可改善大部分患者的平衡功能,但并非所有患者平衡功能均恢复正常.运用动态平衡仪进行平衡康复训练对于已行耳石复位但仍有平衡障碍的患者有益.     

Mal de debarquement and posture: reduced reliance on vestibular and visual cues

OBJECTIVE: The neural mismatch theory assumes that the intersensory conflicts leading to motion sickness are resolved by changes in the relative weighting of the various senses that contribute to orientation. If this sensory rearrangement persists after disembarkment, it might result in mal de debarquement (MD): ataxia and a rocking sensation sometimes felt after landing. The objective of the present study was to examine possible changes in sensory organization in naval crew members with differing susceptibility to MD with computerized dynamic posturography (CDP). STUDY DESIGN: Cross-sectional parallel-group design. METHODS: Seventeen subjects susceptible to MD (SMD) and 17 subjects nonsusceptible to MD (NSMD) (healthy male volunteers aged 18-22) participated in the study. CDP was performed twice with each subject, before and immediately after sailing, using the EquiTest system (NeuroCom, Inc., Clackamas, OR). RESULTS: The SMD group showed a significant reduction in their scores on sensory organization tests 3, 4, and 5 after sailing. Sensory pattern analysis revealed reduced use of inputs from the vestibular and visual systems to maintain balance. Prolonged latencies of the motor responses to unexpected pitch perturbations were also recorded in the postsailing CDP of the SMD group. Reduced performance on the presailing CDP task, which presents the greatest challenge to the vestibular system, was found to control for the presence of MD postsailing. CONCLUSIONS: The results show that MD is associated with postural instability, slower motor reflexes, and larger sways in response to abrupt changes in the body's center of gravity. These findings may be explained by under reliance on vestibular and visual inputs and increased dependence on the somatosensory system for the maintenance of balance.     

Postoperative vestibular dysfunction following head and neck surgery

Patients scheduled for major oncologic head and neck surgery underwent preoperative audiometry and rotational testing for vestibulo-ocular response (VOR). Patients with normal preoperative VOR and SRT less than 45 dB were subsequently retested following surgery for VOR. Patients deemed abnormal on postoperative rotational testing were retested until VOR returned to normal or one year, whichever came first. Eighty patients had normal VOR measured preoperatively. At the first postoperative testing 46 of these patients (58%) were determined to have significant VOR abnormalities. No differences in length of anesthesia, use of hypnotic or narcotic drugs, hepatic and renal abnormalities, and dehydration were noted in the patients who developed abnormal VOR, when compared to the patients who maintained normal VOR. One year post surgery twenty patients (43%) continued to demonstrate vestibular abnormality. The observation that major surgery reduces vestibular response has important monitoring and treatment implications. The integration of this data with the results of endolymphatic surgery are discussed.     

Vestibular rehabilitation outcomes in chronic vertiginous patients through computerized dynamic visual acuity and Gaze stabilization test.

OBJECTIVE: To evaluate the efficiency of the rehabilitative protocols in patients with labyrinthine hypofunction, focusing on computerized dynamic visual acuity test (DVAt) and Gaze stabilization test (GST) specifically evaluating the vestibulo-oculomotor reflex (VOR) changes due to vestibular rehabilitation. DESIGN: Consecutive sample study. SETTING: Day hospital in Ears, Nose, and Throat Rehabilitation Unit. SUBJECTS: Thirty-two patients with chronic dizziness with a mean age of 60.74 years. INTERVENTION: Patients performed one cycle of 12 daily rehabilitation sessions (2 h each) consisting of exercises aimed at improving VOR gain. The rehabilitation program included substitutional and/or habitudinal exercises, exercises on a stability platform, and exercises on a moving footpath with rehabilitative software. MAIN MEASURES: Dizziness Handicap Inventory and Activities-specific Balance Confidence Scale. Computerized dynamic posturography, computerized DVAt, and GST. RESULTS: The patients significantly improved in all the tests. CONCLUSION: Vestibular rehabilitation improved the quality of life by reducing the handicap index and improving the ability in everyday tasks. The recovery of the vestibular-ocular reflex and vestibular-spinal reflex efficiency was objectively proven by instrumental testing. The DVAt and the GST allow to objectively quantify the fixation ability at higher frequencies and speeds (main VOR function). Moreover, these new parameters permit to completely evaluate vestibular rehabilitation outcomes, adding new information to the generally used tests that only assess vestibulospinal reflex.     

Evaluation of Clinical Measures of Equilibrium

Objective: Evaluate the clinical utility of several simple measures of static and dynamic equilibrium in human subjects. In particular, one proposed clinical measure, the Clinical Test of Sensory Integration and Balance (CTSIB) was compared with dynamic posturography for the measurement of postural control capabilities. Study Design: Cross-sectional study of normal subjects and prospective observational study of the same performance measures in vestibular disorder patients. Setting: Academic tertiary care referral center. Participants: Data were collected for all test measures from a group of normal subjects (ages, 20 to 79 years), as well as for a group of patients undergoing treatment for vestibular dysfunction. Results: Data suggest that several semiquantitative clinical tests of static and dynamic equilibrium can be helpful in evaluating and monitoring patients with chronic vestibular dysfunction. The CTSIB results seem to correlate well with dynamic posturography, suggesting that this measure may be useful in identifying patients with abnormal postural control. Formal dynamic posturography testing appears to be more sensitive in detecting abnormal postural control and more exact in defining the specific pattern of dysfunction. Conclusion: Simple clinical measures of static and dynamic equilibrium can reliably distinguish vestibular disorder patients from normal subjects. Dynamic posturography continues to play an important role in the functional evaluation and management of vestibular disorder patients.     

Motor and cognitive performances in pre-lingual cochlear implant adolescents,related with vestibular function and auditory input

Background: Information about the role of auditory input and motor control is limited.

Objectives: Assessment the relationship between auditory and vestibular information with specific motor and cognitive functions.

Methods: Posturography in 17 Pre-lingual Cochlear Implant Adolescents, (PCIA) age 14.06?±?3.05 in four sensory conditions was analyzed: (A) eyes open, cochlear implant (CI) on, (B) eyes open, CI off, (C) eyes closed standing on a foam over a platform (ECFP) with CI on, and (D) ECFP, CI off. Gait velocity (GV) was registered by inertial sensors using a 10-meter test. Vestibulo-ocular reflex (VOR) was evaluated with the video head impulse test (VHIT) and visual spatial skill (VS) assessed with the WISC-V test.

Results: SV had no significant difference between conditions A and B (p?=?.2461). Comparing C and D, SV values decreased when CI was turned on (p?=?.0036). A significant linear relationship between VOR and GV (p?=?.0064) generating the VOR gain loss lower gait. Relationship between VOR and VS scores was no significant (p?=?.685).

Conclusions and significance: Auditory information is a relevant cue when somatosensory and visual inputs are modified and range of vestibular function influence in a dynamic motor activity as gait, facts which must be considered in the neurodevelopment control.     

Vestibulospinal function in two syndromes with spontaneous attacks of vertigo: evaluation by posturography

Two vestibular syndromes comprising attacks of spontaneous vertigo were studied and disturbance of the vestibulospinal reflex was evaluated. Patients with Menière's disease were examined between attacks and patients with a sudden unilateral vestibular loss syndrome at least 3-4 weeks after the initial attack. Posturography, (recording and analysing the postural sway) was used to evaluate the influence of these disorders upon the vestibulospinal reflex. In 50% of the patients, the postural sway was disturbed compared with the performance of a normal control group. Menière's disease had a more pronounced effect on the posturographic results, whereas for the unilateral vestibular loss syndrome the rotation tests showed more asymmetry. It is obvious that the effect upon the vestibulospinal reflex cannot be deduced from the rotational test results. Indeed in a large number of patients discordance between rotational test results and posturography was seen. The presence or absence of attacks during the previous year in patients with Menière's disease had no influence on the presence of abnormal posturographic results. If other complaints of dizziness were mentioned by the patient, posturography was nearly always abnormal. It is evident that a complete evaluation of such patients must include information obtained by posturography.     

Vestibular rehabilitation therapy in children.

OBJECTIVES: Vestibular disturbances are underdiagnosed in children. However, balance impairment may compromise the normal development of affected children. The appropriate therapeutic approach has not been agreed on for this age group. Vestibular rehabilitation therapy has excellent results in adults, but very few data exist regarding its results in children. We evaluated through clinical assessment and computerized dynamic posturography the outcome of children with peripheral vestibular disturbances undergoing vestibular rehabilitation therapy and observed the influence of learning and of central nervous system maturation on posturography retest results. METHODS: Sixteen children (10 boys and 6 girls) with peripheral vestibular disorders (mean age, 8 yr 7 mo) constituted the cohort and were consecutively treated with vestibular rehabilitation therapy. Symptomatic children underwent pre- and posttreatment computerized dynamic posturography. Their outcome was clinically assessed. Another 16 asymptomatic children, paired by sex and age, underwent two computerized dynamic posturography procedures with the same time interval as that of the symptomatic group. RESULTS: All children completed the treatment. Total recovery of symptoms occurred in nine (56.3%) patients, whereas a dramatic partial recovery was observed in the remaining seven (43.7%) children. Posturography Conditions 5 and 6, the vestibular ratio of the sensory analysis, and the composite equilibrium score had a significant quantitative improvement after vestibular rehabilitation therapy. No adverse reactions occurred to the exercises. No statistically significant posturography changes were observed in the asymptomatic children. CONCLUSION: Vestibular rehabilitation therapy seems to be a safe and efficacious therapeutic option in children with peripheral vestibular disturbances.     

Balance sensory organization in children with profound hearing loss and cochlear implants

OBJECTIVES: (1) To determine the feasibility of the use of a modified postural control test under altered sensory conditions in children over 8 years of age, and (2) to assess how deaf children use sensory information for postural control when they have normal or abnormal vestibular responses, and if hearing input from a unilateral cochlear implant, changes their postural behavior. PATIENTS: We selected 36 children, 8 to 11 years of age, with congenital or early-acquired profound sensorineural hearing loss, 13 of them with unilateral cochlear implantation and 22 normal-hearing children. METHODS: The Postural Control (PC) test consists of a force platform with 2 stimulation paradigm conditions: (1) standing on the platform with opened eyes; (2) standing on foam placed on the force platform with closed eyes. Implanted children were tested with the implant turn on and turn off in this condition, in order to evaluate eventual change in the postural control parameters when they have hearing habilitation. The body center of pressure distribution area (COP) and the body sway velocity (SV) were the parameter to evaluate the postural control. RESULTS: Deaf children were classified into two groups according with the vestibular responses: group A (n=28) Children with normal vestibular rotary responses; group B (n=8) children with hypoactive responses. Children in group A had diagnoses of syndromic and non-syndromic hereditary deafness, and children in group B had inner ear malformations, post-meningitis deafness, and one child had non-syndromic hereditary deafness with hypoactive vestibular response. In condition 1, when vestibular, somatosensory and visual information were enabled, the COP and SV values did not show any statistically significant differences between groups A, B and control. In condition 2, when visual information was removed and the somatosensory input strongly modified by standing on the foam, group B showed significant higher COP and SV values than groups A and control (p<0.05). In addition, the scalograms by wavelets of children in group B had higher amplitudes increasing the sway frequencies contents up to 3 Hz, not allowing them to maintain the up right stance in similar stimulation than in condition. Implanted children of the group A and B with the implant turn on, in the condition 2, did not show any significant difference in the SV, comparing when they had the implanted turn off. Group A p=0.395 and group B p=0.465 (Wilcoxon ranked test). CONCLUSION: These findings allow us to confirm that this postural test can be performed in children over 8 years old. Also our results suggest that deaf children with associated hypoactive vestibular responses included in our study, despite the etiology of the deafness, primarily use visual and somatosensory information to maintain their postural control. Hearing habilitation with a unilateral cochlear implant has no effect on the observed sensory organization strategy.     

眼震电图与动态姿势图在良性阵发性位置性眩晕中的临床应用

目的:探讨眼震电图(ENG)及动态姿势描记(DPG)2种前庭功能检查在良性阵发性位置性眩晕(BPPV)中的临床应用。方法:应用ENG与DPG对40例34～79岁的原发性BPPV患者(BPPV组)和20例正常者(对照组)进行检查,其中DPG评定参数选取感觉器官测试(SOT)中前庭感觉评分、本体感觉评分、视觉评分、Romber′s评分和综合评分。结果:40例BPPV患者的ENG检查中,温度试验异常者26例(65.0%);DPG异常者33例(82.5%),并且DPG中均表现为前庭觉评分低,其他几项评分均未见差别。温度试验和DPG两项结果均异常者24例(60.0%),温度试验正常患者中有9例(64.3%)出现前庭觉评分低,在SOT中除前庭觉评分低外其他几项评分均未见明显异常。此外,与对照组比较BPPV组ENG中温度试验和DPG的前庭评分明显异常(P<0.05),并且≥12个月患者上述检查异常程度更高(P<0.05)。结论:ENG与DPG是重要的前庭功能检查方法,二者联合应用能够全面分析BPPV患者前庭功能病变,且BPPV患者病程直接影响其前庭功能。     

Importance of High-Frequency Vestibular Function in the Prognosis of Bilateral Vestibulopathy

ObjectivesThe aim of this study was to investigate whether preserved vestibular function in the high-frequency range influences the prognosis of patients with bilateral vestibulopathy (BVP) after vestibular rehabilitation.MethodsTwenty-four patients followed up with vestibular rehabilitation were recruited. The enrolled patients were divided into two groups according to the preservation of the high-frequency vestibulo-ocular reflex (VOR) based on the video head impulse test (vHIT). The results of computerized dynamic posturography and the Dizziness Handicap Inventory (DHI) survey collected at baseline and at the 6-month follow-up after vestibular rehabilitation therapy were analyzed.ResultsBoth groups showed significantly increased composite and DHI scores after follow-up with vestibular rehabilitation. The group with preserved high-frequency VOR showed a better composite score (P=0.064) and vestibular score (P= 0.008) than the group with lost high-frequency VOR at the 6-month follow up. The DHI score significantly decreased only in the group with lost high-frequency VOR (P=0.047). Among the three vestibular function tests (caloric test, rotary chair test, and vHIT) used to diagnose BVP, only vHIT showed a significant correlation (P=0.015) with a favorable prognosis (composite score ≥70).ConclusionBetter treatment outcomes are likely in patients with BVP with preserved vestibular function in response to high-frequency stimulation, as measured by the vHIT.     

头脉冲试验评价单侧外周前庭病变患者的前庭眼动反射功能

目的 观察单侧外周前庭病变(unilateral peripheral vestibular disorder,uPVD)患者的头脉冲试验(head impulse test,HIT)和冷热试验,探讨HIT在眩晕患者前庭眼动反射功能评价中的临床价值.方法 135例uPVD患者均在同一天进行HIT与冷热试验检查.HIT左右两侧各测试3次.结果 判别方法为:在HIT检查中,以出现≥2次典型的回跳性眼震为阳性结果,出现≤1次典型的回跳性眼震为阴性;记录冷热试验中的半规管轻瘫(canal paresis,CP)值.并以冷热试验为前庭眼动反射功能检查的标准方法,分析HIT的灵敏度、特异度、阳性预测值及阴性预测值.结果 所有135例uPVD患者中,HIT出现3次阳性的有19例,出现2次阳性的为26例,HIT检查阳性率为33.3%,且所有阳性结果均发生在患侧;HIT检查出现1次和未出现回跳性眼震的共90例,阴性率为66.7%.HIT与冷热试验相比较,CP<30%时,HIT阳性6例,阴性58例;CP值为30%～99%,HIT 阳性24例,阴性28例;CP值为100%时,HIT阳性15例,阴性4例.以冷热试验为前庭眼动反射功能标准测试方法,则HIT的灵敏度为54.9%,特异度为90.6%,阳性预测值为86.7%,阴性预测值为64.4%.结论 对uPVD患者水平半规管前庭眼动反射功能进行评价,HIT与冷热试验相比较,其特异度高而灵敏度较低,提示HIT不能取代冷热试验的临床价值或作为其筛查试验方法,但HIT可作为冷热试验的补充,两种方法应结合应用.

Abstract：

Objective To evaluate the function of vestibular ocular reflex (VOR) in patients with unilateral peripheral vestibular disorder (uPVD) by the head impulse test (HIT). Methods The HIT and caloric test were carried out in 135 cases of patients with uPVD. The results of HIT were considered as normal (negative reaction) and abnormal (positive reaction). The results of vestibular function evaluated by caloric test were divided into three kinds, including normal, decreased and deficit according to the degree of canal paresis as less than 30 percent, from 30 to 99 percent, and equal to 100 percent, respectively. The sensitivity, specificity, positive and negative predictive value of HIT in assessing the vestibular function was analyzed. Results For the 135 patients with uPVD, the HIT was normal in 90 ( 66.7% ) cases and abnormal in 45 (33.3%) cases. When the caloric test was normal, the HIT was normal or abnormal in 58 cases and 6 cases, respectively. And when the canal paresis was from 30 to 99 percent, the HIT was normal or abnormal in 28 and 24 cases, respectively. When the vestibular function was deficit (CP was 100% ), the HIT was normal or abnormal in 4 cases and 15 cases, respectively. When the results of caloric test were considered as the standard method to evaluate the VOR, the sensitivity, specificity, positive and negative predictive value of HIT were 54.9%, 90.6%, 86.7%, and 64.4%, respectively. Conclusions When assessing the function of VOR in patients with uPVD, the HIT could not replace the caloric test, but it can be a supplementary method. The information from both the HIT and caloric test can be combined to evaluate the patients with vestibular hypofunction comprehensively.