Brain Correlates of Persistent Postural-Perceptual Dizziness: A Review of Neuroimaging Studies

Persistent postural-perceptual dizziness (PPPD), defined in 2017, is a vestibular disorder characterized by chronic dizziness that is exacerbated by upright posture and exposure to complex visual stimuli. This review focused on recent neuroimaging studies that explored the pathophysiological mechanisms underlying PPPD and three conditions that predated it. The emerging picture is that local activity and functional connectivity in multimodal vestibular cortical areas are decreased in PPPD, which is potentially related to structural abnormalities (e.g., reductions in cortical folding and grey-matter volume). Additionally, connectivity between the prefrontal cortex, which regulates attentional and emotional responses, and primary visual and motor regions appears to be increased in PPPD. These results complement physiological and psychological data identifying hypervigilant postural control and visual dependence in patients with PPPD, supporting the hypothesis that PPPD arises from shifts in interactions among visuo-vestibular, sensorimotor, and emotional networks that overweigh visual over vestibular inputs and increase the effects of anxiety-related mechanisms on locomotor control and spatial orientation.

Cholesteatoma Causing a Horizontal Semicircular Canal Fistula

Horizontal canal fistulas are not uncommon in patients with cholesteatoma. Patients with canal wall down cavities and exposed horizontal canal fistulas develop significant dizziness with wind or suction exposure. Obliteration of mastoid cavities in patients with exposed fistulas can be challenging. We describe a patient with horizontal canal fistula and chronic dizziness from wind exposure who underwent successful mastoid cavity obliteration with preservation of hearing. Patients with horizontal canal fistulas in a canal wall down cavity can be managed with mastoid obliteration for relief of dizziness.

Age-Associated Characteristics of Patients With Chronic Dizziness and Vertigo

Objective: The incidence of dizziness and vertigo is increasing with age, and symptoms lead to significant limitations in daily living and to disability in older patients. Method: Data of 1,752 patients with chronic dizziness/vertigo subjected to a tertiary care, specialized interdisciplinary vertigo center were analyzed. Age, gender, symptoms, medical diagnosis, and Dizziness Handicap Inventory (DHI) were collected based on a questionnaire and analysis of associated patient records. The patients were assigned to 3 age groups (< 41, 41-65, and > 65 years). Results: 33.7% of the patients were older than 65 years. Frequency of symptoms and DHI score increased with age. Older patients reported less frequently about coexisting symptoms such as nausea, headache, tinnitus, ear pressure, and visual impairment. Multisensory deficit, central vertigo, bilateral vestibulopathy, and benign paroxysmal positional vertigo were diagnosed increasingly with age, while persistent postural–perceptual dizziness and vestibular migraine were diagnosed in the younger age groups. Conclusion: In the diagnostic work-up of older patients age-specific characteristics of dizziness/vertigo have to be considered. The older patient generally is more impaired by the symptoms but possibly will not report typical diagnosis-defining symptoms.

VESTIBULAR TESTING IN CHILDREN WITH DIZZINESS AND BALANCE CONCERNS AFTER CONCUSSION: LABORATORY AND CLINICAL RESULTS

Background: Dizziness is the second most common symptom in people who sustain a concussion and there are few reports on vestibular laboratory findings in the concussed pediatric population. Studies to date have shown conflicting findings regarding incidence of peripheral vestibular disorders. Hypothesis/Purpose: The purpose of this study is to report vestibular laboratory and clinical examination findings in concussed youth referred to a multidisciplinary vestibular clinic. Methods: A retrospective chart review was performed for all patients (n=474) seen from August 2017 to March 2020 for a single comprehensive examination in a multidisciplinary pediatric vestibular specialty clinic. Data was extracted from the charts of patients (n=64) with a history of concussion referred because of chronic dizziness and/or imbalance. Each patient was examined by a neurotologist, physical therapist, and audiologist with specialized training in vestibular disorders. Vestibular laboratory testing performed by audiologists included video nystagmography (VNG) evaluation of oculomotor function and BPPV, rotational chair, video head impulse test (vHIT), vestibular evoked myogenic potentials (VEMPs), post-headshake nystagmus, and caloric irrigation. Physical therapy clinical examination included dynamic visual acuity testing (DVA), vestibular/oculomotor screening (VOMS), and sensory organization test (SOT). Not all tests were performed on every patient secondary to factors such as insurance coverage, patient tolerance, and young age. Results: 1 or more components of VOMS was abnormal in 30 of 53 patients examined. DVA was completed on 40 patients, 23 of which were reported as abnormal. SOT was completed on 46 patients, 18 of which demonstrated below normal composite equilibrium scores. Laboratory findings were as follows: VEMPs (n=50) were normal in all but 1 patient, vHIT (n=59), caloric irrigation (n=26), post-headshake nystagmus (n=49), and positional testing (n=55) were normal on all patients tested. Rotational chair (n=60) was performed at 4 different frequencies and revealed low gain in 3 patients. Conclusion: Vestibular laboratory examination was normal in nearly all subjects tested. These results suggest that in concussed youth with chronic dizziness and/or imbalance, laboratory vestibular test outcomes indicative of peripheral dysfunction are rare, which contradicts previous research in this population. In contrast, clinical vestibular assessment was abnormal in more than 50% of subjects examined which suggests that clinicians should use caution interpreting clinical examination findings for diagnosing peripheral vestibular dysfunction. Abnormal clinical examination findings may be indicative of central vestibular conditions such as space and motion intolerance and PPPD in chronically dizzy pediatric patients after concussion. Tables/Figures: [Table: see text][Table: see text]

Episodic versus Chronic Dizziness: An Analysis of Predictive Factors

Objectives: To elucidate differences in demographic and clinical characteristics between patients with episodic and chronic dizziness. Methods: A cross-sectional, observational study of 217 adults referred for dizziness at 1 tertiary center was undertaken. Subjects were split into a chronic dizziness group (>15 dizzy days per month) and an episodic dizziness group (<15 dizzy days per month). Results: 217 adults (average age, 53.7 years; 56.7% female) participated. One-third (n = 74) met criteria for chronic dizziness. Dizziness handicap inventory (DHI) scores were significantly higher in those with chronic dizziness compared to those with episodic dizziness (53.9 vs 40.7; P < .001). Comorbid depression and anxiety were more prevalent in those with chronic dizziness (44.6% and 47.3% vs 37.8% and 35.7%, respectively; P > .05). Abnormal vestibular testing and abnormal imaging studies did not differ significantly between the 2 groups. Ménière’s disease and BPPV were significantly more common among those with episodic dizziness, while the prevalence of vestibular migraine did not differ according to chronicity of symptoms. A multivariate regression that included age, sex, DHI, history of anxiety and/or depression, associated symptoms, and dizziness triggers was able to account for 15% of the variance in the chronicity of dizziness (pseudo- R2 = 0.15; P < .001). Conclusions: Those who suffer from chronic dizziness have significantly higher DHI and high comorbid rates of depression and anxiety than those with episodic dizziness. Our findings show that factors other than diagnosis alone are important in the chronification of dizziness, an observation that could help improve on multimodal treatment options for this group of patients.