Date Published: February 13, 2017
Publisher: Public Library of Science
Author(s): Mark Andrew Miller, Benjamin Thomas Crane, Manabu Sakakibara.
Vection is an illusory perception of self-motion that occurs when a visual motion is presented in the majority of the visual field. We used certainty estimate (CE) and inertial nulling (IN) techniques to study the effect of visual stimuli on roll perception in 10 migraine and 9 control subjects. A visual roll stimulus was presented for 1 to 8s. For the IN method, an inertial stimulus was delivered during the final 1s of the visual stimulus during which subjects judged the direction of perceived motion. The inertial motion was varied to find the point of subjective equality (PSE) at which both responses were equally likely to be reported. For the CE trials, the same durations of visual motion were used but without inertial motion and subjects rated their certainty of motion on a scale of 0–100. The overall difference in PSE between 1s and 8s subjects is significant (p = 0.03). Migraineurs had a ten fold larger effect in IN studies in the 8s than 1s (p = 0.01), but controls did not have a significant difference (p = 0.72). Unlike the control population, in migraineurs the perception of roll increased significantly with the duration of the visual stimulus. There was a large variation between subjects with both the CE and IN measures. The CE measure was poorly correlated with IN measures but demonstrated a similar trend with larger variation between subjects.
Vection is an illusory perception of motion that occurs when a moving visual stimulus is presented in the majority of the visual field . It is important that visual motion be correctly interpreted as vestibular self-motion because the labyrinth cannot always provide reliable information, such as during long, constant velocity motion[2–5]. The sensation of vection is rarely immediate and usually occurs after the stimulus has been present for a period of time on the order of a second when the stimulus accelerates quickly[6, 7].
The current study examined vection in the roll plane using certainty estimates (CE) and inertial nulling (IN) techniques. The major findings of the current study demonstrated was that vection perception with the IN technique increased significantly (p < 0.01) by about ten fold in migraineurs with stimulus duration a trend not present in controls (p = 0.72; Fig 4). A similar but noisier trend was also seen when vection was measured using the CE technique (Fig 6). Vection as measured with the IN and CE techniques were poorly correlated and there were large variations between subjects even within the migraine and control groups. Previous studies in this laboratory used the same IN tool to test vection in control and migraine subjects in the fore-aft plane, demonstrating a good correlation between inertial nulling and certainty estimate in the longer duration trials where vection would be experienced. The roll vection effect was seen in 14 of 19 subjects in the current study with an 8s stimulus but in 8 of 18 subjects with a similar fore-aft stimulus which suggests roll produces a more compelling or universal sensation of vection. The current data are consistent with studies that have shown migraineurs are more likely to demonstrate larger variations in postural sway and visual vertical perception with rotating visual stimuli. Our data demonstrate the use of inertial nulling technique in measuring vection in the roll plane, and the differences between CE and IN. Longer stimulus durations led to enhanced vection in migraine to a greater degree than see in the control subjects in the roll plane. However, there was a large variation between subjects in both the control and migraine group suggesting other factors may have had a significant influence on vection perception. Source: http://doi.org/10.1371/journal.pone.0171332