Misperception of Visual Verticality in Patients with Primary Headache Disorders: A Systematic Review with Meta-Analysis

Clinical Features, Video Head Impulse Test, and Subjective Visual Vertical of Acute and Symptom-Free Phases in Patients with Definite Vestibular Migraine

Background/Objectives: The most frequent neurologic cause of recurrent vertigo is vestibular migraine (VM). However, its diagnosis relies primarily on patients' histories, as specific diagnostic tests for VM are currently lacking. We aimed to examine and compare clinical features, vestibulo-ocular reflexes (VORs), and subjective visual vertical (SVV) between the ictal (IC) and inter-ictal (II) phases in VM patients. Methods: A repeated-measures study involved 31 patients with definite VM. Vestibular function was assessed using a video head impulse test (vHIT) to evaluate VOR results, and SVV testing to determine verticality perception. Otoneurological examination, including migraine-related disability, was noted. Analyses of repeated measures for numerical traits (SVV deviations, VOR, and clinical outcomes) were conducted using a linear mixed model (LMM), with phase, age, and sex as fixed effects and individual-specific random intercepts. Differences between the IC and II phases for dichotomous variables were analyzed using the χ2 or Fisher's exact test. Results: The LMM analysis revealed that SVV deviations were significantly higher ictally (IC-ly) (β = 0.678, p = 1.51 × 10-6) than interictally (II-ly). VOR results remained normal across phases (p > 0.05), and refixation saccades did not differ significantly based on vHIT results (p > 0.05). Nausea (100% vs. 38.71%, p = 6.591 × 10-8), photophobia (100% vs. 35.48%, p = 1.839 × 10-8), and phonophobia (90.32% vs. 6.45%, p = 9.336 × 10-12) were significantly more frequent IC-ly than II-ly. Conclusions: Our findings highlight phase-dependent alterations in spatial orientation, with increased SVV deviations IC-ly despite stable VOR. The significant differences in migraine-associated symptoms reinforce the dynamic nature of VM. These results emphasize the importance of timing in vestibular assessments and suggest that SVV testing during IC VM episodes may enhance diagnostic accuracy.

Test-Retest Reliability of Dynamic Subjective Visual Vertical and Visual Dependency in Older Adults Using Virtual Reality Methods

The perception of verticality is formed through the integration of multisensory gravitational information, including somatosensory, visual, and vestibular inputs. Older adults exhibit visual dependency (VD) as they rely more on visual information to compensate for reduced somatosensory and vertical perception. Increased VD is associated with falls, and the dynamic subjective visual vertical (SVV) is used to assess VD. However, the measurement reliability of dynamic SVV and VD using virtual reality (VR), which has garnered considerable attention in recent years, remains unclear. Therefore, our purpose in this study was to assess the test-retest reliability of dynamic SVVs and VDs using a VR method. We evaluated static and dynamic SVV of 40 older adults using a smartphone-based VR system (SVR-SVV). Dynamic SVV consisted of numerous spheres on the background rotating clockwise (CW-SVV) or counterclockwise (CCW-SVV). Each SVV measurement consisted of one set of 10 trials. VD was calculated as the mean value of dynamic SVV minus the mean values of static SVV. A re-test was conducted after one week. Reliability was analyzed using Bland-Altman plots and intraclass correlation coefficients (ICC 2, k) for each SVV measure. We observed no systematic bias in any of the SVV values, which were 0.1° (SD = 2.8°), 13.3° (SD = 8.3°), -12.8° (SD = 6.9°), and 15.7° (SD = 8.1°) for static SVV, CW-SVV, CCW-SVV, and VD, respectively. Test-retest reliability was good for static SVV (ICC = .817, p < .001), CW-SVV (ICC = .896, p < .001) and excellent for CCW-SVV (ICC = .914, p < .001), VD (ICC = .937, p < .001). The dynamic SVV and VD measurements using SVR-SVV demonstrated good test-retest reliability. Moreover, the SVR-SVV is more portable than conventional methods, making it highly useful in clinical practice.

What visuospatial perception has taught us about the pathophysiology of vestibular migraine

PURPOSE OF REVIEW

A decade has passed since vestibular migraine (VM) was formally established as a clinical entity. During this time, VM has emerged amongst the most common cause of episodic vertigo. Like all forms of migraine, VM symptoms are most prominent during individual attacks, however many patients may also develop persistent symptoms that are less prominent and can still interfere with daily activities.

RECENT FINDINGS

Vestibular inputs are strongly multimodal, and because of extensive convergence with other sensory information, they do not result in a distinct conscious sensation. Here we review experimental evidence that supports VM symptoms are linked to multisensory mechanisms that control body motion and position in space.

SUMMARY

Multisensory integration is a key concept for understanding migraine. In this context, VM pathophysiology may involve multisensory processes critical for motion perception, spatial orientation, visuospatial attention, and spatial awareness.

Static Subjective Visual Vertical (SVV) in Patients with Vestibular Migraine

BACKGROUND

 Vestibular migraine (VM) is one of the common causes of episodic dizziness, but it is underdiagnosed and poorly understood. Previous research suggests that otolith reflex pathway performance is often impaired in this patient group, leading to altered perception of roll plane stimuli. Clinically, this perception can be measured with subjective visual vertical (SVV) testing.

PURPOSE

 The aim of this study is to compare static SVV performance (absolute mean SVV tilt, variance) in a cohort of patients diagnosed with VM to results obtained from clinically derived normative data.

STUDY DESIGN

 Retrospective case review.

STUDY SAMPLE

 Ninety-four consecutive patients between 18 and 65 years of age diagnosed with VM were included in this comparison to clinically derived normative data.

DATA COLLECTION AND ANALYSIS

 Retrospective chart review was completed. Demographic data, symptom report, and vestibular laboratory results were documented. SVV performance was documented in terms of absolute mean SVV tilt and response variance.

RESULTS

 Abnormal mean SVV tilt was described in 54% (n = 51) of patients with VM. Including abnormal response variance increased those identified with abnormal presentation to 67% (n = 63). Laboratory findings were insignificant for semicircular canal function, but of those with abnormal ocular vestibular myogenic potential results (n = 30), 77% (n = 23) demonstrated both abnormal SVV and utriculo-ocular reflex performance. There were no associations noted for SVV performance and demographic or other self-report variables.

CONCLUSION

 Absolute mean SVV tilt and response variance are often abnormal in patients diagnosed with VM. These findings support theories suggesting atypical intralabyrinthine integration within the vestibular nuclei and cerebellar nodular pathways.

Care Gaps and Recommendations in Vestibular Migraine: An Expert Panel Summit

Vestibular migraine (VM) is an increasingly recognized pathology yet remains as an underdiagnosed cause of vestibular disorders. While current diagnostic criteria are codified in the 2012 Barany Society document and included in the third edition of the international classification of headache disorders, the pathophysiology of this disorder is still elusive. The Association for Migraine Disorders hosted a multidisciplinary, international expert workshop in October 2020 and identified seven current care gaps that the scientific community needs to resolve, including a better understanding of the range of symptoms and phenotypes of VM, the lack of a diagnostic marker, a better understanding of pathophysiologic mechanisms, as well as the lack of clear recommendations for interventions (nonpharmacologic and pharmacologic) and finally, the need for specific outcome measures that will guide clinicians as well as research into the efficacy of interventions. The expert group issued several recommendations to address those areas including establishing a global VM registry, creating an improved diagnostic algorithm using available vestibular tests as well as others that are in development, conducting appropriate trials of high quality to validate current clinically available treatment and fostering collaborative efforts to elucidate the pathophysiologic mechanisms underlying VM, specifically the role of the trigemino-vascular pathways.

Brain Processing of Visual Self-Motion Stimuli in Patients With Migraine: An fMRI Study

OBJECTIVE

To investigate the behavioral and neuronal responses of patients with migraine to a visual simulation of self-motion through a virtual roller coaster ride in comparison to controls.

METHODS

Twenty consecutive patients with migraine from a university-based hospital headache clinic and 20 controls were included. Participants underwent an experiment where a visually displayed self-motion paradigm was presented based on customized roller coaster videos during fMRI. Within each video, blocks of motion stimulation were interleaved with low-speed upward motion in a random order. In the scanning intervals and after the experiment, participants rated their perceived level of vestibular symptoms and motion sickness during the videos. We hypothesized that patients with migraine will perceive more motion sickness and that it correlates with different central processing and brain responses.

RESULTS

Compared to controls, patients with migraine reported more dizziness (65% vs 30%; p = 0.03) and motion sickness (Simulator Sickness Questionnaire score 47.3 [95% confidence interval (CI), 37.1, 57.5] vs 24.3 [95% CI, 18.2, 30.4]) as well as longer symptom duration (01:19 minutes [95% CI, 00:51, 01:48] vs 00:27 minutes [95% CI, 00:03, 00:51]) and intensity (visual analogue scale score 0-100, 22.0 [95% CI, 14.8, 29.2] vs 9.9 [95% CI, 4.9, 14.7]) during the virtual roller coaster ride. Neuronal activity in patients with migraine was more pronounced in clusters within the superior (contrast estimate 3.005 [90% CI, 1.817, 4.194]) and inferior occipital gyrus (contrast estimate 1.759 [90% CI, 1.062, 2.456]), pontine nuclei (contrast estimate 0.665 [90% CI, 0.383, 0.946]), and within the cerebellar lobules V/VI (contrast estimate 0.672 [90% CI, 0.380, 0.964]), while decreased activity was seen in the cerebellar lobule VIIb (contrast estimate 0.787 [90% CI, 0.444, 1.130]) and in the middle frontal gyrus (contrast estimate 0.962 [90% CI, 0.557, 1.367]). These activations correlated with migraine disability (r = -0.46, p = 0.04) and motion sickness scores (r = 0.32, p = 0.04). We found enhanced connectivity between the pontine nuclei, cerebellar areas V/VI, and interior and superior occipital gyrus with numerous cortical areas in patients with migraine but not in controls.

CONCLUSIONS

Migraine is related to abnormal modulation of visual motion stimuli within superior and inferior occipital gyrus, middle frontal gyrus, pontine nuclei, and cerebellar lobules V, VI, and VIIb. These abnormalities relate to migraine disability and motion sickness susceptibility.