With the aim of improving parameter identification and, eventually, evaluating driver distraction with changes in gaze direction, we applied a genetic algorithm (GA) method to identify parameters for an existing vesti...With the aim of improving parameter identification and, eventually, evaluating driver distraction with changes in gaze direction, we applied a genetic algorithm (GA) method to identify parameters for an existing vestibulo-ocular reflex (VOR) model. By changing the initial inputs to the GA and fixing two parameters pertaining to the horizontal direction, we achieved improved parameter identification with a lower mean-square error. The influence of driver distraction on eye movement with changes in gaze direction was evaluated from the difference between the predicted and observed VOR in the vertical axis. When a driver was given an additional mental workload, the mean-square error between the measured and simulated values was bigger than that in the absence of the mental workload. This confirmed the relationship between driver distraction and eye movement in the vertical direction. We hope that this method can be applied in evaluating driver distraction.展开更多
Objectives The video head impulse test(vHIT)is used as a measure of compensation yet it’s stability in patients with vestibular pathology is unknown.Methods 144 patients(n=72 female,mean 54.46±15.8 years)were gr...Objectives The video head impulse test(vHIT)is used as a measure of compensation yet it’s stability in patients with vestibular pathology is unknown.Methods 144 patients(n=72 female,mean 54.46±15.8 years)were grouped into one of three primary diagnoses(Peripheral,Central,or Mixed).Subjects were further categorized based on sex(male versus female),ear(left versus right;ipsilesional versus contralesional),age(six groups ranging from 19 to 84 years),and duration between visits(five groups,mean 191.46±SE 29.42 days,median 55.5 days).The gain of the VOR during passive head rotation was measured for each semicircular canal(horizontal,anterior,posterior).Results There was no difference in the VOR gain within any semicircular canal between the two visits(horizontal:p=0.179;anterior:p=0.628;posterior:p=0.613).However,the VOR gain from the horizontal canals was higher than the vertical canals for each visit(p<0.001).Patients diagnosed with peripheral vestibular pathology had significantly lower(p≤0.001)horizontal semicircular canal gains at each visit.There was no difference in VOR gain between sex(p=0.215)or age groupings(p=0.331).Test-retest reliability of vHIT in patient subjects is good(ICC=0.801)and the VOR gain values across two separate visits were significant and positively correlated(r=0.67)regardless of sex,ear,age,or duration between visits.Conclusion The vHIT is a stable measure of VOR gain over two different times across a variety of vestibular patients with no influence of age or sex.展开更多
The ears are air-filled structures that are directly impacted during blast exposure.In addition to hearing loss and tinnitus,blast victims often complain of vertigo,dizziness and unsteady posture,suggesting that blast...The ears are air-filled structures that are directly impacted during blast exposure.In addition to hearing loss and tinnitus,blast victims often complain of vertigo,dizziness and unsteady posture,suggesting that blast exposure induces damage to the vestibular end organs in the inner ear.However,the underlying mechanisms remain to be elucidated.In this report,single vestibular afferent activity and the vestibuloocular reflex(VOR)were investigated before and after exposure to blast shock waves(~20 PSI)delivered into the left external ear canals of anesthetized rats.Single vestibular afferent activity was recorded from the superior branch of the left vestibular nerves of the blast-treated and control rats one day after blast exposure.Blast exposure reduced the spontaneous discharge rates of the otolith and canal afferents.Blast exposure also reduced the sensitivity of irregular canal afferents to sinusoidal head rotation at 0.5e2Hz.Blast exposure,however,resulted in few changes in the VOR responses to sinusoidal head rotation and translation.To the best of our knowledge,this is the first study that reports blast exposure-induced damage to vestibular afferents in an animal model.These results provide insights that may be helpful in developing biomarkers for early diagnosis of blast-induced vestibular deficits in military and civilian populations.展开更多
文摘With the aim of improving parameter identification and, eventually, evaluating driver distraction with changes in gaze direction, we applied a genetic algorithm (GA) method to identify parameters for an existing vestibulo-ocular reflex (VOR) model. By changing the initial inputs to the GA and fixing two parameters pertaining to the horizontal direction, we achieved improved parameter identification with a lower mean-square error. The influence of driver distraction on eye movement with changes in gaze direction was evaluated from the difference between the predicted and observed VOR in the vertical axis. When a driver was given an additional mental workload, the mean-square error between the measured and simulated values was bigger than that in the absence of the mental workload. This confirmed the relationship between driver distraction and eye movement in the vertical direction. We hope that this method can be applied in evaluating driver distraction.
基金This work was supported in part by the Department of Defense under the Neurosensory and Rehabilitation Research Award Program(Grant Award W81XWH-15-1-0442)the Psychological Health/Traumatic Brain Injury Research Program Complex Traumatic Brain Injury Rehabilitation Research Clinical Trial Award(Grant Award W81XWH-17)。
文摘Objectives The video head impulse test(vHIT)is used as a measure of compensation yet it’s stability in patients with vestibular pathology is unknown.Methods 144 patients(n=72 female,mean 54.46±15.8 years)were grouped into one of three primary diagnoses(Peripheral,Central,or Mixed).Subjects were further categorized based on sex(male versus female),ear(left versus right;ipsilesional versus contralesional),age(six groups ranging from 19 to 84 years),and duration between visits(five groups,mean 191.46±SE 29.42 days,median 55.5 days).The gain of the VOR during passive head rotation was measured for each semicircular canal(horizontal,anterior,posterior).Results There was no difference in the VOR gain within any semicircular canal between the two visits(horizontal:p=0.179;anterior:p=0.628;posterior:p=0.613).However,the VOR gain from the horizontal canals was higher than the vertical canals for each visit(p<0.001).Patients diagnosed with peripheral vestibular pathology had significantly lower(p≤0.001)horizontal semicircular canal gains at each visit.There was no difference in VOR gain between sex(p=0.215)or age groupings(p=0.331).Test-retest reliability of vHIT in patient subjects is good(ICC=0.801)and the VOR gain values across two separate visits were significant and positively correlated(r=0.67)regardless of sex,ear,age,or duration between visits.Conclusion The vHIT is a stable measure of VOR gain over two different times across a variety of vestibular patients with no influence of age or sex.
文摘The ears are air-filled structures that are directly impacted during blast exposure.In addition to hearing loss and tinnitus,blast victims often complain of vertigo,dizziness and unsteady posture,suggesting that blast exposure induces damage to the vestibular end organs in the inner ear.However,the underlying mechanisms remain to be elucidated.In this report,single vestibular afferent activity and the vestibuloocular reflex(VOR)were investigated before and after exposure to blast shock waves(~20 PSI)delivered into the left external ear canals of anesthetized rats.Single vestibular afferent activity was recorded from the superior branch of the left vestibular nerves of the blast-treated and control rats one day after blast exposure.Blast exposure reduced the spontaneous discharge rates of the otolith and canal afferents.Blast exposure also reduced the sensitivity of irregular canal afferents to sinusoidal head rotation at 0.5e2Hz.Blast exposure,however,resulted in few changes in the VOR responses to sinusoidal head rotation and translation.To the best of our knowledge,this is the first study that reports blast exposure-induced damage to vestibular afferents in an animal model.These results provide insights that may be helpful in developing biomarkers for early diagnosis of blast-induced vestibular deficits in military and civilian populations.
