Vestibular-autonomic interactions: beyond orthostatic dizziness

Abstract

Purpose of reviewThis review aims to summarize the current literature describing vestibular-autonomic interactions and to describe their putative role in various disorders' clinical presentations, including orthostatic dizziness and motion sensitivity. Recent findingsThe vestibular-autonomic reflexes have long been described as they relate to cardiovascular and respiratory function. Although orthostatic dizziness may be in part related to impaired vestibulo-sympathetic reflex (orthostatic hypotension), there are various conditions that may present similarly. A recent clinical classification aims to improve identification of individuals with hemodynamic orthostatic dizziness so that appropriate recommendations and management can be efficiently addressed. Researchers continue to improve understanding of the underlying vestibular-autonomic reflexes with recent studies noting the insular cortex as a cortical site for vestibular sensation and autonomic integration and modulation. Work has further expanded our understanding of the clinical presentation of abnormal vestibular-autonomic interactions that may occur in various conditions, such as aging, peripheral vestibular hypofunction, traumatic brain injury, and motion sensitivity.

Vestibular syncope: clinical characteristics and mechanism

“…When the head moves downward (e.g., sitting), the fluid is now momentarily pumped toward the upper body, increasing the preload and blood pressure. Vestibular signals decrease sympathetic tone, thereby enabling the resumption of a normotensive state 1,2 . This vestibulo‐sympathetic reflex is fast but imprecise, as it is an antecedent autonomic response implemented through a feed‐forward open‐loop system 24,25 .…”

“…The vestibular system, together with the baroreflex pathway, plays a substantial role in maintaining cardiovascular homeostasis during motion 1,2 . Neurons in the caudal part of the vestibular nuclear complex, including the inferior and medial vestibular nuclei, regulate sympathetic activity through various connections with brainstem autonomic nuclei 1–3 .…”

“…The vestibular system, together with the baroreflex pathway, plays a substantial role in maintaining cardiovascular homeostasis during motion 1,2 . Neurons in the caudal part of the vestibular nuclear complex, including the inferior and medial vestibular nuclei, regulate sympathetic activity through various connections with brainstem autonomic nuclei 1–3 . Given the stimulus characteristics (head motion) and short‐latency action of 100 to 200 msec, this vestibular‐driven reflex regulates autonomic activity in a feed‐forward manner 1–3 .…”

“…Given the stimulus characteristics (head motion) and short‐latency action of 100 to 200 msec, this vestibular‐driven reflex regulates autonomic activity in a feed‐forward manner 1–3 . In contrast, the baroreflex system operates with a feedback mechanism that controls the autonomic activity 1–3 …”

“…1,2 Neurons in the caudal part of the vestibular nuclear complex, including the inferior and medial vestibular nuclei, regulate sympathetic activity through various connections with brainstem autonomic nuclei. [1][2][3] Given the stimulus characteristics (head motion) and short-latency action of 100 to 200 msec, this vestibular-driven reflex regulates autonomic activity in a feed-forward manner. [1][2][3] In contrast, the baroreflex system operates with a feedback mechanism that controls the autonomic activity.…”