Does Cognitive Dysfunction Correlate With Dizziness Severity in Meniére's Disease Patients

Microbial alpha diversity in the intestine negatively correlated with disease duration in patients with Meniere's disease

Ménière's disease (MD) is characterized by loss of balance and hearing disorders. Although there is known to be endolymphatic hydrops involved in the pathological process, the pathogenesis of the disease is still largely unclear. Approximately half of patients with MD suffer from depressive symptoms and high levels of several stress hormones were observed in MD and depression, simultaneously. Recently, gut microbes have been shown to influence the function of the central nervous system in humans through their metabolites. We studied the intestinal microbiota of 10 patients with MD and 11 healthy donors (HD). Significant negative correlations were found between disease duration and alpha diversity indexes of gut microbes in patients with MD. The relative abundance of the species Butyricicoccus ambiguous taxa was increased in patients with MD compared with that of HD. In contrast, Oscillospiraceae UCG-002/UCG-005 ambiguous taxa and Anaerovoracaceae (Eubacterium) brachy group uncultured bacterium were increased in the relative abundance of HD than that of patients with MD. The relative abundance of the Butyricicoccus species was positively correlated with disease duration. Thus, these compositional alterations of gut microbes in patients with MD are associated with inner ear pathologies, such as endolymphatic hydrops, by changing the metabolite profiles in the intestine.

Association of Vestibular Disorders and Cognitive Function: A Systematic Review

OBJECTIVES

The purpose of this study is to consolidate and condense the available evidence about the potential association between vestibular diseases and cognitive impairment.

DATA SOURCES AND METHODS

A systematic search was conducted on four English databases (PubMed, Embase, Web of Science, Cochrane Library) from the time of library construction to March 2024. The study incorporated various keywords such as "vestibular disorders," "vertigo," "dizziness," "Meniere's disease," "benign paroxysmal positional vertigo," "vestibular migraine," "vestibular neuritis," "labyrinthitis," "bilateral vestibular disease," as well as "cognitive function" and "cognitive dysfunction." A qualitative review was conducted to look for and assess pertinent studies.

RESULTS

A total of 45 publications were incorporated, encompassing prevalent vestibular disorders, mostly targeting individuals in the middle-aged and older demographic. The findings indicate that individuals with vestibular disorders experience varying levels of cognitive impairment, which is evident in different aspects, with visuospatial cognitive deficits being more prominent. Furthermore, patients with chronic vestibular syndromes are more prone to cognitive dysfunction. Lastly, the hippocampus plays a crucial role in the intricate vestibular neural network.

CONCLUSION

The findings of this comprehensive review indicate that vestibular disorders can result in impairments across various aspects of cognitive functioning, particularly in visuospatial cognition. The underlying mechanism may be associated with a decrease in the size of the hippocampus. Individuals suffering from chronic vestibular dysfunction exhibit a higher likelihood of experiencing cognitive deficits.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:4858-4872, 2024.

Neurological update: neuro-otology 2023

Much has changed since our last review of recent advances in neuro-otology 7 years ago. Unfortunately there are still not many practising neuro-otologists, so that most patients with vestibular problems need, in the first instance, to be evaluated and treated by neurologists whose special expertise is not neuro-otology. The areas we consider here are mostly those that almost any neurologist should be able to start managing: acute spontaneous vertigo in the Emergency Room-is it vestibular neuritis or posterior circulation stroke; recurrent spontaneous vertigo in the office-is it vestibular migraine or Meniere's disease and the most common vestibular problem of all-benign positional vertigo. Finally we consider the future: long-term vestibular monitoring and the impact of machine learning on vestibular diagnosis.

Analysis of cognitive function and its related factors after treatment in Meniere’s disease

A growing body of research recently suggested the association between vestibular dysfunction and cognitive impairment. Meniere’s disease (MD), a common clinical vestibular disorder, is usually accompanied by hearing loss and emotional stress, both of which may mediate the relationship between vestibule dysfunction and cognition. It is currently unknown whether the cognitive decline in MD patients could improve through treatment and how it relates to multiple clinical characteristics, particularly the severity of vertigo. Therefore, in the present study, the MD patients were followed up for 3, 6, and 12 months after treatment, and the cognitive functions, vertigo symptoms, and related physical, functional, and emotional effects of the patients were assessed using the Montreal Cognitive Assessment (MoCA) and Dizziness Handicap Inventory (DHI), aiming to explore the change in cognition before and after therapy and the correlation with various clinical features. It was found that cognitive decline in MD patients compared to healthy controls before therapy. Importantly, this cognitive impairment could improve after effective therapy, which was related to the severity of vertigo, especially in functional and physical impacts. Our results support the view that vestibular dysfunction is a potentially modifiable risk factor for cognitive decline.

Cognitive function in Meniere's disease

Meniere's disease is an otological disease characterized by various symptoms that include episodic peripheral vertigo, sensorineural hearing loss, tinnitus, and aural fullness, all of which deteriorate the maintenance of daily activities. We aimed to investigate cognitive function in Meniere's disease patients and compare their results to those of healthy controls. Eighteen patients diagnosed with definite Meniere's disease without any psychiatric, neurological or otological comorbidity, and 30 healthy controls with normal cognitive functions were included in the study. General cognitive status, attention, verbal memory, visual memory, executive and visuospatial function were measured by detailed neuropsychological tests in both groups. In the patients with Meniere's disease, pure-tone hearing thresholds, and speech discrimination scores were also measured. Patients with Meniere's disease showed lower levels of performance in the trail making test, Oktem verbal memory processes, Rey Complex Figure Test, Wisconsin Card Sorting Test, semantic and phonemic fluency than did healthy controls. In other words, there were deficits in attention, recognition and recall in verbal memory, recall in visual memory, visual spatial construction, and planning skills in patients with Meniere's disease. Education years and depression scores of participants had a significant effect on cognitive function in all groups. This study is an update and confirmation of the findings of studies showing cognitive impairment in patients with Meniere's disease. In addition to previous findings, this study found a decrease in executive function performance in patients with Meniere's disease compared to healthy controls. Unlike previous studies, this study comprehensively addressed all cognitive functions and included a control group. Our results emphasize that executive functions, which are high-level cognitive processes, may affect the compliance of patients with Meniere's disease treatment and follow-up processes.

Visuospatial Cognitive Dysfunction in Patients with Vestibular Loss

OBJECTIVE

To characterize visuospatial and nonvisuospatial cognitive domains affected by vestibular loss and determine whether patient-reported outcomes measures (PROMs) correlate with performance on neuropsychological tests.

STUDY DESIGN

Cross-sectional study.

SETTING

University-based tertiary medical center.

PATIENTS

Sixty-nine age-matched subjects: 25 patients with bilateral vestibular loss (BVL), 14 patients with unilateral vestibular loss (UVL), and 30 normal controls (NC).

INTERVENTIONS

Neuropsychological tests used to assess visuospatial and auditory short-term and working memory, number magnitude representation, executive function, and attention. Validated PROMs used to evaluate quality of life and subjective cognitive impairment.

MAIN OUTCOME MEASURES

Performance on neuropsychological tests and scores on PROM surveys.

RESULTS

BVL and UVL patients performed significantly worse than NC subjects on tasks requiring visuospatial representation compared with NC subjects ( p < 0.01). BVL patients demonstrated decreased performance on spatial representation tasks compared with UVL and NC subjects ( p < 0.05 and p < 0.05, respectively). All subject groups performed similarly on tasks assessing nonvisuospatial cognitive domains, such as auditory short-term and working memory, executive function, and attention. PROMs did not seem to correlate with performance on neuropsychological tasks.

CONCLUSION

Patients with vestibular loss exhibit impairments in tasks requiring visuospatial representation but perform similarly to NC subjects in tasks of auditory working memory, executive function, or attention. Currently available questionnaires may be insufficient to screen patients for cognitive deficits.