Visual?vestibular stimulation interferes with information processing in young and older humans

Abstract

Attention has been implicated in postural control and other tasks requiring sensory integration. The purpose of this study was to investigate the role of attention in sensory-motor processing of vestibular and combined visual-vestibular information during seated rotations using a dual-task interference approach. We hypothesized that auditory information processing would be influenced by concurrent visual-ocular, vestibulo-ocular, or combined visual-vestibulo-ocular processing. We further hypothesized that the effect would be greater in older subjects. Twenty older subjects (10 women, 10 men, 69.3+/-3.2 years) and 20 young subjects (10 women, 10 men, 23.5+/-2.9 years) were asked to perform information-processing tasks while they underwent several types of vestibular, visual-vestibular, and ocular motor paradigms. The information-processing tasks were: (1) an auditory simple reaction-time task (SRT), (2) an auditory go-no-go (disjunctive) reaction-time task (DRT), and (3) an auditory forced-choice task (CRT). The visual-vestibular-ocular motor conditions included: (1) no movement/darkness (NO), (2) no movement/fixation (FIX), (3) no movement/pursuit (P), (4) earth-vertical axis rotation (EVAR) in darkness, (5) EVAR with fixation (E-FIX), (6) off-vertical axis rotation (OVAR) in darkness, and (7) OVAR with fixation (O-FIX). Results showed that older subjects had longer reaction times for all combinations of stimulus condition and reaction-time task compared with young subjects. Compared with the NO baseline, reaction times during EVAR were longer for young and older subjects and during OVAR were longer for the young subjects. For FIX and P, the reaction times during P exceeded those during FIX and during NO for both groups. For E-FIX and O-FIX, reaction times did not differ from those during EVAR and OVAR. The interference with information processing by concurrent vestibular stimulation in the dark may be based upon cortical inhibition of auditory processes by vestibular stimulation. Eye movements induced by EVAR showed an increased phase lead during reaction-time tasks, suggesting altered vestibulo-ocular reflex (VOR) dynamics, possibly based on cerebellar-mediated changes in velocity storage. Since fixation of a head-fixed visual target did not add to the effect of rotation in the dark, a further implication of our results is that VOR-fixation while performing a concurrent information-processing task may be accomplished primarily by VOR suppression rather than by VOR cancellation.

Quantitative Evaluation of Mental Workload by Using Model of Involuntary Eye Movement

“…Our results were consistent with the previous studies by other researchers [2], [8], [9]. These results suggest that VOR measures enable quantification of a MWL.…”

“…Recently, many researcher groups have started focusing on studying other kinds of physiological measures, such as involuntary reflexes, in the hopes of finding better MWL assessment techniques. For example, vestibule-ocular reflex (VOR) has grabbed the attention of researchers and has been examined to assess its effectiveness in quantifying MWLs [2], [3]. This VOR method of quantifying MWL has six major advantages over other existing MWL measures: The VOR method is (1) objective, (2) does not interrupt the main tasks, (3) measurable in real-time, (4) quickly reflects MWL, (5) not physically obtrusive, and (6) does not require large equipment.…”

“…For example, vestibule-ocular reflex (VOR) has grabbed the attention of researchers and has been examined to assess its effectiveness in quantifying MWLs [2], [3]. This VOR method of quantifying MWL has six major advantages over other existing MWL measures: The VOR method is (1) objective, (2) does not interrupt the main tasks, (3) measurable in real-time, (4) quickly reflects MWL, (5) not physically obtrusive, and (6) does not require large equipment. Taking from previous studies, our present study used the n-back tasks to determine if VOR responses could be reasonable measures for quantifying a person's MWLs.…”

Cálculo de los tiempos de circularvección en una población con patología vestibular. Influencia del estímulo visual

“…La funcionalidad de esta interacción se ve afectada por múltiples factores, como la atención, la realización de otras actividades 6 , situaciones de ingravidez 7 , neurotóxicos 8 , medicación que afecte a receptores GABA, la edad 9 , el sexo 10 o los traumatismos, como es el caso de pacientes con latigazo cervical 11 .…”

Calculation of the Circularvection Times in a Population With Vestibular Pathology. Influence of Visual Stimulus

“…Por medio de la interacción visuovestibular es posible examinar las diferentes informaciones relevantes al movimiento para elaborar una respuesta más adecuada 5 . La funcionalidad de esta interacción se ve afectada por múltiples factores, como la atención, la realización de otras actividades 6 , situaciones de ingravidez 7 , neurotóxicos 8 , medicación que afecte a receptores GABA, la edad 9 , el sexo 10 o los traumatismos, como es el caso de pacientes con latigazo cervical 11 . Esta necesaria interacción funcional se mantiene en los pacientes cuando la función vestibular es insuficiente, lo que demuestra una plasticidad del fenómeno de interacción visuovestibular máxima.…”