Vestibular Stimulation and Forearm Blood Flow

Abstract

Forty-six adult male subjects have been exposed to strong vestibular stimulation produced by controlled cyclic nodding of the head while being rotated in the horizontal plane on a turntable at constant angular velocity. Forearm blood flow was measured with a mercury-in-rubber strain gauge plethysmograph standardized against a conventional plethysmographic technique. There was wide variability among the subjects in the amount of vestibular stimulation needed to cause nausea just short of emesis. Motion sickness, when unequivocal, was accompanied by increased blood flow in the forearm and nearly always by an increase in the circumference of the forearm when venous flow was not occluded. Resistant subjects, in whom motion sickness was either minimal or not apparent, showed either no increase in forearm blood flow or increases that were equivocal. It is concluded that increased muscle blood flow may now be added to antidiuresis, nausea, pallor, and sweating, as a physiological response common to the vasovagal syndrome and to motion sickness caused by vestibular stimulation. A possible explanation of the results and their relation to aviation are discussed.

An electrophysiological and anatomical study of afferents reaching the cerebellar uvula in the rabbit

“…Ablation of both nodulus and uvula abolished the kinetosic syndrome (Tyler & Bard, 1949;Wang & Chinn, 1956). However, although several autonomic functions are altered in motion sickness, an appreciable modification of blood pressure and heart rate has never been reported in either animals or man (Tyler & Bard, 1949;Sunahara, Johnson & Taylor, 1964). This is in contrast with our report of marked effects on cardiovascular variables following stimulation of the uvula (Bradley et al 1987a).…”

What is nausea? A historical analysis of changing views

“…The most evident of these responses are cold-sweating (Cheung et al, 2011; Hemingway, 1944; Nobel et al, 2012; Sclocco et al, 2015), changes in cutaneous thermoregulatory vascular tone (Nalivaiko et al, 2015), and pallor (Cassano et al, 1989; Kolev et al, 1997). Changes in skin blood flow that result in pallor are not accompanied by alterations in blood pressure (Sunahara et al, 1987; Sunahara et al, 1964), showing that they are not due to a global increase in sympathetic nervous system activity. In fact, there is evidence of increased blood flow to muscle and decreased blood flow to the skin during motion sickness (Cheung et al, 2001).…”

Motion sickness, nausea and thermoregulation: The “toxic” hypothesis

“…The first study where skin blood flow was assessed during MS provocation, reported a 50-60% fall in finger pulse volume indicative of vasoconstriction 7 . Several other early studies demonstrated that MS is associated with an increase in forearm blood flow 35,36 . However, they were conducted by means of venous occlusion plethysmography (a method based on the volume changes in the forearm), and thus could not determine whether blood flow increased in the skin or in the muscles of the forearm.…”

“… 7 Several other early studies demonstrated that MS is associated with an increase in forearm blood flow. 35,36 However, they were conducted by means of venous occlusion plethysmography (a method based on the volume changes in the forearm), and thus could not determine whether blood flow increased in the skin or in the muscles of the forearm. Using the difference between forearm and finger temperature as a surrogate measure of cutaneous vascular tone, Nobel and colleagues concluded that MS attenuates cutaneous vasoconstriction provoked by immersion in the cold water.…”