A Relationship Between Unexplained Dizziness and Beta-amyloid Plaques Among Older Adults – Mayo Clinic Longitudinal Study of Aging

Abstract

Background and ObjectiveBeta-amyloid (Aβ) plaque deposition, which can be detected by amyloid C-11 labeled Pittsburgh Compound B (11C-PiB) Positron Emission Tomography (PET) imaging, is a key feature of Alzheimer’s disease (AD) and occurs years before the onset of symptoms. It is well-documented that the onset of AD initially involves degeneration of cholinergic systems in the posterior parietal-temporal, medial-temporal, and posterior-cingulate regions, which have a strong relationship with the vestibular labyrinth. In the context of an aging population, the symptoms-related vestibular system ranks among the most frequent complaints in primary care but remains unexplained in 40–80% of cases over the age of 65. The objective of this study was to evaluate the cross-sectional and longitudinal association between the symptoms-related vestibular system and Aβ-PET imaging among older adults.MethodsA retrospective study design. The study included 5707 participants without dementia, enrolled in the Mayo Clinic Study of Aging (mean age (SD) 74.4 (9.7) years) with cognitive evaluation and information about symptoms-related vestibular system, mainly dizziness or lightheadedness, at baseline and for every 15 months.ResultsOf the 5707, 924 (16%) participants were complaining of ‘unexplained’ dizziness or lightheadedness. The estimated risk of developing symptoms of dizziness or lightheadedness at 10 years was 49%. Data suggested that AD-related risk factors including, age, male gender, lower education, high comorbidity index, high-density lipoprotein, balance problems, presence of neurocognitive and neurobehavioral outcomes, and brain-related changes can contribute to the risk of developing ‘unexplained’ dizziness or lightheadedness among older adults. Adjusting for the risk factors, a statistically significant association between ‘unexplained’ dizziness or lightheadedness and Aβ-PET imaging was evident [HR = 1.8, P = 0.009]. This association seems to be significantly modulated by psychological outcomes including, depressive symptomatology and anxiety [HR = 1.0, P = 0.001].Conclusions‘Unexplained’ dizziness or lightheadedness was associated with Aβ plaque deposition among older adults. This association seems to be modulated by psychological outcomes. Although these symptoms can be linked by a common cause, it may suggest functional dizziness, also known as psychogenic dizziness or persistent postural-perceptual dizziness. Further studies are needed to support the findings.