Isolated Otolith Dysfunction in Persistent Postural-Perceptual Dizziness

Effect of viewing distance on dynamic visual acuity

BackgroundPatients with dizziness and unsteadiness are commonly prescribed gaze stability exercises at varying target distances to manage vestibular impairments but lack objective tools to monitor progress. Maintaining gaze stability during head motion at near distances demands greater eye velocity relative to head velocity due to vergence and increased translational eye rotation demands.ObjectivesThis study compared dynamic visual acuity (DVA) during yaw and pitch at both near and far distances in patients and healthy controls.MethodsThis study includes individuals with unilateral vestibular deafferentation (UVD), veterans with dizziness yet healthy vestibular function, and healthy controls. The computerized DVA at near (50 cm) and far (200 cm) distances were collected. Data analysis included comparisons of near and far DVA in yaw and pitch planes.ResultsA total of 94 participants (34 UVD, 24 veterans with dizziness, 36 controls) were included. Near-distance DVA was significantly worse than far-distance DVA for the entire sample and within each group (p < 0.001).ConclusionsNear-distance DVA is more challenging than far-distance DVA across populations and planes of head rotation. Near-distance DVA may serve as a robust measure of vestibulo-ocular reflex function and offers a practical means for patients to self-monitor the effects of gaze stability training.

vHIT and fHIT in Patients With Migraine, Vestibular Migraine, and Persistent Postural-Perceptual Dizziness

OBJECTIVE

Impairment in the integration of different vestibular stimuli is the proposed mechanisms in vestibular migraine (VM). In this study, it was aimed to assess the vestibulo-ocular reflex (VOR) and dynamic visual acuity (DVA) in patients with VM and to compare the results with migraine without vestibular symptoms (MwoV), and persistent postural-perceptual dizziness (PPPD) to find out if there are discriminative differences and search for a correlation with the levels of anxiety.

METHODS

Twenty-two patients with MwoV, 23 patients with VM, 22 patients with PPPD, and 23 healthy controls (HC) were studied. Video head impulse test (vHIT) and functional head impulse test (fHIT) without and with an optokinetic background (OB) were performed. Percentage of correctly identified optotypes (CA%) was considered for the fHIT test. Beck anxiety inventory (BAI) was used to assess anxiety.

RESULTS

Lateral canal vHIT gain of the patient groups were not different from the healthy controls (p > 0.05). fHIT and fHIT/OB CA% results of all patient groups were lower than the HC (p < 0.005), and VM patients had the lowest scores for both tests. BAI scores of the PPPD patients were the highest and a correlation between anxiety levels, and fHIT results could not be identified (p > 0.05).

CONCLUSION

Prominent CA% drop by the use of an OB was the main finding in patients with VM. This discriminative feature was not correlated with anxiety scores. Difficulty in resolving the conflict between visual and vestibular inputs seem to be the underlying mechanism.

LEVEL OF EVIDENCE

3 Laryngoscope, 135:857-863, 2025.

Predictors of Chronic Dizziness in Acute Unilateral Vestibulopathy: A Longitudinal Prospective Cohort Study

OBJECTIVE

Chronic dizziness after acute unilateral vestibulopathy (AUVP) causes significant social and economic burdens. This study aims to identify predictors of chronic dizziness.

STUDY DESIGN

Prospective, longitudinal cohort study.

SETTING

ENT departments from secondary and tertiary hospitals.

METHODS

Participants meeting the Barany Society's diagnostic criteria for AUVP were included. Evaluations occurred within 0 to 21 days (T1), and at 4 (T2) and 10 weeks (T3) postonset. The primary outcome measure was the Dizziness Handicap Inventory (DHI) at 6 months, with a score >30 indicating chronic dizziness. Five clusters of predictors were assessed at T1-3: central vestibular compensation, visual dependence, movement exposure, psychological factors, and balance performance. Separate linear regression models for T1, T2, and T3 were constructed to explain the variability in the 6-month DHI score. Receiver operating characteristics analyses were conducted to predict chronic dizziness.

RESULTS

From June 2021 to January 2024, 103 participants (55.2 ± 16.6 years old, 49 women) were included. The regression models explained the variability in the 6-month DHI score by 33.0% at T1, 47.6% at T2, and 64.0% at T3 (P < .001), including psychological factors (T1, T2, T3), visual dependence (T2, T3), and static balance performance (T3). Cutoff values for the Vestibular Activities Avoidance Instrument (23/54), Visual Vertigo Analog Scale (33.5/100), and Hospital Anxiety and Depression Scale-Anxiety (7.5/21) at 10 weeks postonset predicted chronic dizziness.

CONCLUSION

Higher psychological burden, increased visual dependence, and poorer static balance performance were associated with chronic dizziness. Cutoff values were determined to identify individuals with AUVP at risk for chronic dizziness.

Photodynamic therapy-induced precise attenuation of light-targeted semicircular canals for treating intractable vertigo

Vertigo is a common symptom of various diseases that affects a large number of people worldwide. Current leading treatments for intractable peripheral vertigo are to intratympanically inject ototoxic drugs such as gentamicin to attenuate the semicircular canal function but inevitably cause hearing injury. Photodynamic therapy (PDT) is a noninvasive therapeutic approach by precisely targeting the diseased tissue. Here, we developed a PDT-based method for treating intractable peripheral vertigo in a mouse model using a polymer-coated photosensitizer chlorin e6 excited by red light. We found that a high dose of PDT attenuated the function of both semicircular canals and otolith organs and damaged their hair cells. Conversely, the PDT exerted no effect on hearing function or cochlear hair-cell viability. These results suggest the therapeutic potential of PDT for treating intractable peripheral vertigo without hurting hearing. Besides, the attenuation level and affected area can be precisely controlled by adjusting the light exposure time. Furthermore, we demonstrated the potential of this therapeutic approach to be minimally invasive with light irradiation through bone results. Thus, our PDT-based approach for attenuating the function of the semicircular canals offers a basis for developing a less-invasive and targeted therapeutic option for treating vertigo.

Graviception Uncertainty, Spatial Anxiety, and Derealization in Patients with Persistent Postural-Perceptual Dizziness

Objectives: Persistent Postural-Perceptual Dizziness (PPPD) is a frequent diagnosis in patients with chronic dizziness, ineffective postural control, visual dependence, and emotional symptoms. Methods: 53 patients with PPPD (25-84 years old) and 53 adults (29-84 years old) with no vestibular disease agreed to participate in this study. Assessments included: vestibular function tests (sinusoidal yaw rotation and vestibular-evoked myogenic potentials); accuracy and precision of Subjective Visual Vertical (SVV) estimation while static and during on-axis yaw rotation; static posturography with open/closed eyes and 30° neck extension, while standing on hard/soft surface; questionnaires on symptoms of unsteadiness, spatial anxiety, dizziness-related handicap, anxiety/depression, depersonalization/derealization, and perceived stress. After preliminary bivariate analyses, analysis of covariance was performed on the measurements of postural sway, spatial anxiety, and dizziness-related handicap (p < 0.05). Results: Higher intraindividual variability (reduced precision) on SVV estimations was evident in patients with PPPD compared to adults with no vestibular disease, which was related to the length of postural sway, to velocity displacement in the sagittal plane, as well as to spatial anxiety and common mental symptoms (including depersonalization/derealization symptoms). Covariance analysis showed contribution of these factors to the dizziness-related handicap reported by the patients. Conclusions: Unprecise graviception could be a contributing factor to the postural instability and mental symptoms reported by patients with PPPD, which in turn contribute to their dizziness-related handicap.

Chronic Unilateral Vestibular Hypofunction: Insights into Etiologies, Clinical Subtypes, Diagnostics and Quality of Life

Background/Objectives: Chronic unilateral vestibular hypofunction (UVH) can lead to disabling vestibular symptoms and a decrease in quality of life. The aim of this study was to investigate etiologies, clinical subtypes, symptoms, and quality of life (QoL) in patients with chronic UVH. Methods: A retrospective study was performed on 251 UVH patients in a tertiary referral center. Inclusion criteria comprised reduced or absent caloric responses, with a caloric asymmetry ratio ≥25%. Patients with central vestibular pathology, symptom duration <3 months, and incomplete responses to questionnaires were excluded. Patient records were assessed for etiologies, secondary vestibular diagnoses, clinical subtypes, and questionnaires related to QoL. Additionally, multiple linear regression analysis was performed to evaluate factors influencing QoL. Results: Thirteen different etiologies were identified, with Menière's Disease as the most prevalent (31%, n = 79). The most frequently reported secondary vestibular diagnoses were benign paroxysmal positional vertigo (BPPV) (21%, n = 54) and persistent postural perceptual dizziness (PPPD) (19%, n = 47). Five distinct clinical subtypes were identified: recurrent vertigo with UVH (47%), rapidly progressive UVH (25%), idiopathic/unknown UVH (18%), slowly progressive UVH (8%), and congenital UVH (2%). Over 80% of UVH patients experienced moderate-to-severe handicap, as indicated by the Dizziness Handicap Inventory. Approximately 20-25% of UVH patients exhibited moderate-to-severe depression and anxiety, based on the Hospital Anxiety and Depression Scale. Multiple linear regression analyses demonstrated that the presence of PPPD significantly reduced QoL in chronic UVH patients. Conclusions: Chronic UVH is a heterogeneous disorder. Secondary vestibular diagnoses like BPPV and PPPD often co-exist and can significantly impact QoL. A structured diagnostic approach and tailored interventions are crucial to address the diverse needs of UVH patients.

French adaptation and validation of the Niigata PPPD Questionnaire: measure of severity of Persistent Postural-Perceptual Dizziness and its association with psychiatric comorbidities and perceived handicap

Persistent Postural-Perceptual Dizziness (PPPD) is a functional vestibular condition. Despite being the most common chronic neuro-otologic disorder, it remains undertreated. The Niigata PPPD Questionnaire (NPQ), developed by Yagi et al. in 2019 to assess the severity of PPPD, could be a useful tool to help in the screening and diagnosis of this condition. This study aimed to validate a French version of the NPQ and make it an available assessment tool. Moreover, we aimed to understand the characteristics of PPPD patients better. The NPQ was translated and adapted into French. 50 PPPD patients, 50 patients with vestibular disorders without PPPD, and 50 healthy controls were included. They answered the adapted NPQ and additional questionnaires assessing trait (STAI) and state anxiety (HADS-A), depression (HADS-D) and handicap related to dizziness (DHI). The NPQ's reliability was assessed by Cronbach's alpha. Intergroup comparisons and multiple linear regressions were conducted to examine the characteristics of PPPD patients compared to vestibular patients and healthy controls, to validate NPQ's reliability, and to explore the effect of clinical parameters and treatment with selective serotonin reuptake inhibitors. Receiver operating characteristic (ROC) curves were carried out to determine the diagnostic values of the NPQ total score and sub-scores. Relations between NPQ and reported handicap, depression and anxiety were evaluated by correlations between questionnaire scores. The internal consistency was high (>0.8) for all NPQ subscales and the total score. Intergroup comparisons showed a significantly higher NPQ total score and sub-scores in the PPPD group compared to the two others. The ROC curve analysis showed a significant, but poor, discrimination of NPQ (AUC = 0.664) and its subscales. DHI scores, depressive symptoms and trait anxiety were significantly higher in PPPD patients than in vestibular patients and healthy controls. State anxiety did not differ between patients with PPPD and vestibular patients without PPPD. Finally, there was a significant correlation between the NPQ and the DHI. Our study provides a better understanding of PPPD symptomatology and its assessment. It showed that the NPQ is a reliable tool that can assist in symptom assessment for a French-speaking population.

Modernising vestibular assessment

BACKGROUND

There is a high prevalence of dizziness, vertigo and balance symptoms in the general population. Symptoms can be generated by many inner-ear vestibular disorders and there are several diagnostic tests available that can help identify the site of the vestibular lesion. There is little consensus on what diagnostic tests are appropriate, with diagnostics either not completed or minimally performed, leading to missed diagnosis, unsatisfactory results for patients and costs to healthcare systems.

METHODS

This study explored the literature for different neuro-vestibular diagnostic tests not currently considered in the traditional standard vestibular test battery, and examined how they fit effectively into a patient care pathway to help quickly and succinctly identify vestibular function.

RESULTS

A vestibular patient care pathway is presented for acute and subacute presentation of vestibular disorders.

CONCLUSION

An accurate diagnosis following a rigorous anamnesis and vestibular testing is paramount for successful management and favourable outcomes.

Age-related differences in the characteristics of persistent postural-perceptual dizziness

Objective

To investigate differences in the clinical characteristics of patients with persistent postural-perceptual dizziness (PPPD) according to age.

Methods

We retrospectively reviewed 143 patients diagnosed with PPPD. Patients were classified into three groups by age: young group (19 to 44 years, n = 60), middle-age group (45 to 64 years, n = 56), old group (65 to 85 years, n = 27). Demographic data, scores of the Dizziness Handicap Inventory (DHI), the Niigata PPPD Questionnaire (NPQ), the Hospital Anxiety and Depression Scale (HADS), precipitating conditions, and the results of vestibular function tests including caloric testing, video head impulse test (vHIT), cervical and ocular vestibular evoked myogenic potentials (cVEMPs and oVEMPs), and posturography, were compared among the three groups.

Results

While there were no significant differences in the scores of the DHI or NPQ, the total score and anxiety score in HADS in the young group were significantly higher than in the old group (p < 0.05, each). On the other hand, for precipitating conditions, the rate of peripheral vestibular diseases was significantly greater in the old group (77.8%) compared to the young group (41.7%, p < 0.01). There was no significant difference in the results of caloric testing, vHIT, cVEMPs, or oVEMPs among the three groups. For posturography, the velocity of the center of pressure with eyes-open as well as with eyes-closed was significantly greater in the old group compared to the young group and the middle-age group (p < 0.005, respectively).

Conclusion

The clinical characteristics of PPPD were different according to age. Young patients tended to have stronger anxiety than old patients whereas the old patients had a higher proportion of peripheral vestibular diseases among the precipitating conditions compared to young patients.

Habituation disorders in auditory middle latency response of persistent postural-perceptual dizziness patients

Objectives

To study habituation disorders in auditory middle latency response (AMLR) to repetitive stimuli of persistent postural-perceptual dizziness (PPPD) patients.

Subjects

Twenty-eight PPPD (10 men and 18 women, mean 59.5 years of age, 26-81 years of age) were enrolled. For comparison, data of 13 definite vestibular migraine (VM) patients (3 men, 10 women, mean age 45.5), 13 definite unilateral Meniere's disease (MD) patients (2 men, 11 women, mean age 50.6), and 8 healthy control (HC) subjects (2 men, 6 women, mean age 37.1) in the previous study were utilized.

Methods

The electrodes were placed on the vertex and the spinal process of the fifth cervical vertebra. Clicks (0.1 msec, 70 dB nHL) were binaurally presented and averaged (800 times). Averaged responses were divided into 4 sets (S1 to S4) according to the temporal order. As peaks, Na, and Pa were identified, and relative Na-Pa amplitudes in S2-S4 to S1 were analyzed.

Results

The mean relative amplitude of PPPD patients showed lack of habituation (potentiation) as shown in VM patients, although the extent of potentiation was weaker than VM. Comparison of relative S4 amplitudes showed significant differences among the 4 groups (p = 0.0013 one-way ANOVA), Multiple comparison revealed significant differences between PPPD and MD (p = 0.0337 Dunnet's test).

Conclusion

PPPD patients showed lack of habituation (potentiation) of Na-Pa amplitude in AMLR to repetitive stimuli. Lack of habituation (potentiation) might be associated with sensory processing disorders in PPPD.

Preceding Benign Paroxysmal Positional Vertigo as a Trigger for Persistent Postural-Perceptual Dizziness: Which Clinical Predictors?

OBJECTIVE

Persistent postural-perceptual dizziness (PPPD) is a syndrome described as secondary, when it is the consequence of an organic disorder (s-PPPD), or primary, when no somatic triggers can be identified. We evaluated a group of patients diagnosed as s-PPPD, with Benign Positional Paroxysmal Vertigo (BPPV) as the main somatic trigger, with the aim of identifying the predictive clinical elements of evolution towards PPPD.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral center.

PATIENTS

We evaluated 126 patients diagnosed with PPPD; 54 patients were classified as p-PPPD (43%) and 72 as s-PPPD (57%). Of these, 51 patients had BPPV as a somatic trigger of PPPD, and in this group, we evaluated the prevalence of some clinical features (age, sex, latency between the onset of BPPV and the final diagnosis, recurrence of BPPV and the presence of migraine headache) for comparison with a group of patients who suffered from BPPV without an evolution towards PPPD (control group).

RESULTS

In the group with PPPD secondary to BPPV, we found a significantly higher mean age and a longer latency between the onset of BPPV and the final diagnosis compared to the control group. No difference between the two groups was found regarding sex, recurrence rate and the presence of migraine headache.

CONCLUSIONS

The parameters most involved as potential precipitants of PPPD after BPPV were the age of the patients and a long latency between the onset of BPPV and the final diagnosis; the mean age of the subjects who developed PPPD following BPPV was significantly higher. These findings lead us to emphasize the importance of the early identification and treatment of BPPV, especially in older patients.

Validity and reliability of the Niigata PPPD Questionnaire in a Western population

PURPOSE

To analyze the psychometric properties of the Niigata Questionnaire (NPQ) for use in a European population with persistent postural-perceptual dizziness (PPPD).

METHODS

Observational study included 140 patients with different vestibular conditions. Construct validity, internal consistency and concurrent validity were analyzed. Intra-class correlation coefficient (ICC), standard error of measurement (SEM) and minimal detectable change (MDC) were calculated. Receiver operating characteristic (ROC) curve was used to test diagnostic values.

RESULTS

Of the 140 patients, 47 had a diagnosis of PPPD. Factorial analysis showed a single-factor structure and concurrent validity analysis showed strong correlations with other instruments. Cronbach alpha coefficients of 0.938 for the total score, 0.869 for the standing and gait subscale, 0.803 for the subscale of movements and 0.852 for the visual stimulation subscale were obtained. The reproducibility was substantial except for the standing subscale, which could be considered moderate. For the standing, movement and visual stimulation subscales and for the total score, the SEM was 3.27, 2.41, 2.50 and 6.63, respectively, and the MDC was 6.40, 4.72, 4.91 and 12.99, respectively. The NPQ total score showed an area under the curve (AUC) of 0.661, a sensitivity of 72.34 and a specificity of 55.91 for discriminating between PPPD and other vestibular disorders.

CONCLUSIONS

The NPQ is feasible for use in a Western population and presents a uni-factorial structure, high internal consistency and strong correlation with other instruments. The reliability can be considered substantial. The NPQ has low accuracy in discriminating between subjects with or without PPPD.

Predictors of persistent postural-perceptual dizziness (PPPD) and similar forms of chronic dizziness precipitated by peripheral vestibular disorders: a systematic review

BACKGROUND

The literature on predictors of persistent postural-perceptual dizziness (PPPD) following peripheral vestibular insults has not been systematically reviewed.

METHODS

We systematically reviewed studies on predictors of PPPD and its four predecessors (phobic postural vertigo, space-motion discomfort, chronic subjective dizziness and visual vertigo). Investigations focused on new onset chronic dizziness following peripheral vestibular insults, with a minimum follow-up of 3 months. Precipitating events, promoting factors, initial symptoms, physical and psychological comorbidities and results of vestibular testing and neuroimaging were extracted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

We identified 13 studies examining predictors of PPPD or PPPD-like chronic dizziness. Anxiety following vestibular injury, dependent personality traits, autonomic arousal and increased body vigilance following precipitating events and visual dependence, but not the severity of initial or subsequent structural vestibular deficits or compensation status, were the most important predictors of chronic dizziness. Disease-related abnormalities of the otolithic organs and semi-circular canals and age-related brain changes seem to be important only in a minority of patients. Data on pre-existing anxiety were mixed.

CONCLUSIONS

After acute vestibular events, psychological and behavioural responses and brain maladaptation are the most likely predictors of PPPD, rather than the severity of changes on vestibular testing. Age-related brain changes appear to have a smaller role and require further study. Premorbid psychiatric comorbidities, other than dependent personality traits, are not relevant for the development of PPPD.

A study of otolith function in patients with orthostatic dizziness

BACKGROUND

Orthostatic dizziness (OD) is the dizziness that occurs when moving from a sitting or a supine to a standing position. It is typically thought to be connected to orthostatic hypotension (OH). The otolithic control of respiratory and cardiovascular system through vestibulosympathetic reflex has been the focus of considerable recent interest. This study aimed to evaluate the relationship between the orthostatic dizziness and otolith organ function.

METHODS

This study was carried on 50 adults aged from 18 to 50 years with normal peripheral hearing. Subjects were divided into two groups: controls (GI): 20 healthy adults and study group (GII): 30 patients who were complaining of OD. Patients were submitted to; blood pressure measurement in sitting and standing positions, combined vestibular-evoked myogenic potentials (VEMPs) and subjective visual vertical and horizontal tests (SVV) and (SVH).

RESULTS

The study group showed abnormal absent cVEMP, oVEMP. There were also statistically significant differences of P13 and N23 latencies and (P13N23) amplitudes between the two groups in the left ears. Both groups differed significantly in SVH values deviated to the left side. Study group were further subdivided into ten patients with OH and 20 patients with OD without OH. The both study subgroups showed abnormal absent cVEMP, oVEMP and abnormal SVH. OH patients showed statistically significant differences of cVEMP waves P13, N23 latencies in the left ears when compared with the control.

CONCLUSIONS

Otolith malfunction may be the cause of orthostatic dizziness (OD) in patients with and without orthostatic hypotension.

Isolated bilateral posterior semicircular canal hypofunction: comparison with bilateral vestibulopathy

BACKGROUND

Chronic unsteadiness is a common complaint at vestibular clinics. Bilateral vestibulopathy (BVP) is a major cause of chronic unsteadiness but is often overlooked. Although diagnostic criteria for BVP have been established by the Barany Society, isolated vertical canal hypofunction can remain undiagnosed. Recently, the video head-impulse test has enabled clinicians to assess vertical semicircular canal function at clinics.

OBJECTIVE

This study aimed to compare the features of isolated bilateral posterior semicircular canal hypofunction (IBPH) with those of BVP diagnosed based on the Barany criteria.

METHODS

The clinical data of 8 IBPH patients that had been diagnosed using our diagnostic criteria (sex, age, subjective symptoms, questionnaire, video head-impulse test and stabilometry) were analyzed and compared with those of 6 BVP patients diagnosed using the Barany criteria.

RESULTS

The IBPH patients were all aged >70 years, while the age range of the BVP patients was wider. While the BVP patients complained of both oscillopsia during body movement and unsteadiness in darkness, the IBPH patients complained of unsteadiness in darkness without oscillopsia during body movement. The IBPH patients exhibited milder clinical findings than the BVP patients.

CONCLUSION

IBPH can cause mild unsteadiness in the elderly.

SIGNIFICANCE

Clinicians should be aware that IBPH can cause unsteadiness in the elderly.

[Expert consensus on the diagnosis of isolated otolith dysfunction]

Isolated otolith dysfunction(iOD) involves a group of unexplained vestibular syndromes that manifest clinically as a sense of translation, tilting or floating, and blurred vision with head movement, with normal semicircular canal function but abnormal otolith function on laboratory vestibular testing. As vestibular medicine has gained widespread popularity in recent years, increasing attention has also been paid to iOD and case reports, clinical studies and diagnostic criteria have been published. However, there is no consensus document to guide the diagnosis of this disease in China. In this context, the Special Committee on Vertigo of China Medical Education Association organized a group of domestic experts in vestibular medicine and formulated this diagnostic consensus after thorough discussion based on the latest evidence in China and abroad, in order to promote the best clinical practice for iOD.

Clinical features of persistent postural-perceptual dizziness with isolated otolith dysfunction as revealed by VEMP and vHIT findings

Background

Persistent postural-perceptual dizziness (PPPD) is a relatively new disease entity, with diagnostic criteria published by the Bárány Society. PPPD is often preceded by a peripheral or central vestibular disorder. It is not clear how coexisting deficits due to preceding vestibular disorders affect PPPD symptoms.

Objective

This study aimed to characterize the clinical features of PPPD with or without isolated otolith dysfunction using vestibular function tests.

Methods

The study included 43 patients (12 males and 31 females) who were diagnosed with PPPD and completed oculomotor-vestibular function tests. The Dizziness Handicap Inventory (DHI), Hospital Anxiety and Depression Scale (HADS), Niigata PPPD Questionnaire (NPQ), and Romberg test for stabilometry were examined. The 43 patients with PPPD were classified into four categories based on vestibular evoked myogenic potential (VEMP) and video head impulse test (vHIT) results: normal function for both semicircular canals and otoliths (normal), isolated otolith dysfunction (iOtoDys), isolated semicircular canal dysfunction (iCanalDys), and dysfunction of both otoliths and semicircular canals (OtoCanalDys).

Results

Among the 43 patients with PPPD, the iOtoDys group was the largest (44.2%), followed by the normal group (37.2%), iCanalDys group (9.3%), and OtoCanalDys group (9.3%). Eight of the 19 iOtoDys patients showed both abnormal cVEMP and oVEMP responses unilaterally or bilaterally (both sacculus and utriculus damage type), whereas 11 showed either an abnormal cVEMP or an abnormal oVEMP response (either sacculus or utriculus damage type). In a three-group comparison of the both sacculus and utriculus damage type, the either sacculus or utriculus damage type, and the normal group, the mean total, functional, and emotional DHI scores were significantly higher for the both sacculus and utriculus damage type than for the either sacculus or utriculus damage type. The Romberg ratio, a measure of stabilometry, was significantly higher for the normal group than for the both sacculus and utriculus damage type and the sacculus or utriculus damage type in the iOtoDys group.

Conclusions

The coexistence of sacculus and utriculus damage may exacerbate dizziness symptoms in patients with PPPD. Determining the presence and extent of otolith damage in PPPD may provide useful information on the pathophysiology and treatment strategies of PPPD.