Exploring assessment of balance using virtual reality in patients at risk of chemotherapy-induced peripheral neuropathy.

BACKGROUND: Chemotherapy-induced peripheral neuropathy (CIPN) is a common dose-limiting toxicity for people treated for cancer. Impaired balance and falls are functional consequences of CIPN. Virtual reality (VR) technology may be able to assess balance and identify patients at risk of falls. AIMS: To assess the impact of potentially neurotoxic chemotherapy on balance using VR, and explore associations between VR balance assessment, falls and CIPN. METHODS: This prospective, repeated measures longitudinal study was conducted at two Australian cancer centres. Eligible participants were commencing adjuvant chemotherapy containing a taxane for breast cancer, or oxaliplatin for colorectal cancer (CRC), per institutional guidelines. Balance assessments using VR were conducted at baseline, end of chemotherapy and 3 and 6 months after completion of chemotherapy. Participants also completed a comprehensive CIPN assessment comprising clinical and patient-reported outcomes, and recorded falls or near falls. RESULTS: Out of 34 participants consented, 24 (71%) had breast cancer and 10 (29%) had CRC. Compared to baseline, balance threshold was reduced in 10/28 (36%) evaluable participants assessed at the end of chemotherapy, and persistent in 7/22 (32%) at 6 months. CIPN was identified in 86% at end of chemotherapy and persisted to 6 months after chemotherapy completion in 73%. Falls or near falls were reported by 12/34 (35%) participants, and were associated with impaired VR balance threshold (P = 0.002). CONCLUSIONS: While VR balance assessment was no better at identifying CIPN than existing measures, it is a potential surrogate method to assess patients at risk of falls from CIPN.

Suppression head impulse test paradigm (SHIMP) characteristics in people with Parkinson's disease compared to healthy controls.

The suppression head impulse test paradigm (SHIMP) is a newly described indicator of vestibular function which yields two measures: vestibulo-ocular reflex (VOR) gain and a saccadic response. It is an alternative and complementary test to the head impulse test paradigm (HIMP). Parkinson's disease (PD) has known saccadic and central vestibular pathway dysfunction. This paper is the first description of SHIMP VOR gain and saccade characteristic in this population. This prospective observational study measured the SHIMP VOR gain and saccade characteristics in 39 participants with idiopathic PD and compared this to 40 healthy controls (HC). The effect of group, demographic variables and SHIMP characteristics were evaluated. SHIMP VOR gains were not significantly different between groups (p = 0.10). Compared to HC, the PD group mean SHIMP peak saccade velocity was significantly reduced by an average of 77.07°/sec (p < 0.001), and SHIMP saccade response latency was longer, with an average delay of 23.5 ms (p = 0.003). SHIMP saccade peak velocity was also associated with both head impulse velocity (p = 0.002) and SHIMP VOR gain (p = 0.004) variables, but there was no significant influence of these variables when SHIMP saccade peak velocity was considered as a predictor of PD (p = 0.52-0.91). VOR gains were unaffected by PD. PD-specific saccadic dysfunction, namely reduced peak saccade velocities and prolonged response latencies, were observed in the SHIMP-induced saccade responses. VOR gain using slow phase eye velocity is preferred as the indicator of vestibular function in the SHIMPs paradigm as non-vestibular factors affected saccade peak velocity.

Static and dynamic otolith reflex function in people with Parkinson's disease.

PURPOSE: Parkinson's disease (PD) is a neurodegenerative disorder with possible vestibular system dysfunction. This study reports the transient and sustained functions of the otoliths and their reflex pathways in PD compared to healthy controls (HC) and determines if otolith function relates to previous fall history. METHODS: Forty participants with PD and 40 HC had their otolith function assessed. Transient saccular and utricular-mediated reflexes were assessed by cervical and ocular vestibular evoked myogenic potentials (cVEMPs and oVEMPs, respectively) elicited by air-conducted stimulus (clicks) and bone-conducted vibration (light tendon hammer taps). Static otolith function was assessed by the Curator Subjective Visual Vertical (SVV) test. RESULTS: Compared to HC, the PD group had significantly more absent cVEMP responses to both clicks (47.5% vs. 30%, respectively, p = 0.03) and taps (21.8% vs. 5%, respectively, p = 0.002). Only the PD group had bilaterally absent tap cVEMPs, this was related to previous falls history (p < 0. 001). In both groups, click oVEMPs were predominantly absent, and tap oVEMPs were predominantly present. The PD group had smaller tap oVEMP amplitudes (p = 0.03) and recorded more abnormal SVV responses (p = 0.01) and greater error on SVV compared to HC, p < 0.001. SVV had no relationship with VEMP responses (p = 0.14). CONCLUSIONS: PD impacts on cVEMP reflex pathways but not tap oVEMP reflex pathways. Bone-conducted otolith stimuli (taps) are more robust than air-conducted sound stimuli (clicks) for both o and cVEMPs. A lack of association between SVV and VEMP responses suggest that static and dynamic otolith functions are differentially affected in PD.

Strabismus Measurements with Novel Video Goggles.

PURPOSE: To assess the validity of a novel, simplified, noninvasive test for strabismus using video goggles. DESIGN: Cross-sectional method comparison study in which the new test, the strabismus video goggles, is compared with the existing reference standard, the Hess screen test. PARTICIPANTS: We studied 41 adult and child patients aged ≥6 years with ocular misalignment owing to congenital or acquired paralytic or comitant strabismus and 17 healthy volunteers. METHODS: All participants were tested with binocular infrared video goggles with built-in laser target projection and liquid crystal display shutters for alternate occlusion of the eyes and the conventional Hess screen test. In both tests, ocular deviations were measured on a 9-point target grid located at 0±15° horizontal and vertical eccentricity. MAIN OUTCOME MEASURES: Horizontal and vertical ocular deviations at 9 different gaze positions of each eye were measured by the strabismus video goggles and the Hess screen test. Agreement was quantified as the intraclass correlation coefficient. Secondary outcomes were the utility of the goggles in patients with visual suppression and in children. RESULTS: There was good agreement between the strabismus video goggles and the Hess screen test in the measurements of horizontal and vertical deviation (intraclass correlation coefficient horizontal 0.83, 95% confidence interval [0.77, 0.88], vertical 0.76, 95% confidence interval [0.68, 0.82]). Both methods reproduced the characteristic strabismus patterns in the 9-point grid. In contrast to Hess screen testing, strabismus video goggle measurements were even possible in patients with comitant strabismus and visual suppression. CONCLUSIONS: The new device is simple and is fast and accurate in measuring ocular deviations, and the results are closely correlated with those obtained using the conventional Hess screen test. It can even be used in patients with visual suppression who are not suitable for the Hess screen test. The device can be applied in children as young as 6 years of age.

Neural basis of new clinical vestibular tests: otolithic neural responses to sound and vibration.

Extracellular single neuron recording and labelling studies of primary vestibular afferents in Scarpa's ganglion have shown that guinea-pig otolithic afferents with irregular resting discharge are preferentially activated by 500 Hz bone-conducted vibration (BCV) and many also by 500 Hz air-conducted sound (ACS) at low threshold and high sensitivity. Very few afferent neurons from any semicircular canal are activated by these stimuli and then only at high intensity. Tracing the origin of the activated neurons shows that these sensitive otolithic afferents originate mainly from a specialized region, the striola, of both the utricular and saccular maculae. This same 500 Hz BCV elicits vestibular-dependent eye movements in alert guinea-pigs and in healthy humans. These stimuli evoke myogenic potentials, vestibular-evoked myogenic potentials (VEMPs), which are used to test the function of the utricular and saccular maculae in human patients. Although utricular and saccular afferents can both be activated by BCV and ACS, the differential projection of utricular and saccular afferents to different muscle groups allows for differentiation of the function of these two sensory regions. The basic neural data support the conclusion that in human patients in response to brief 500 Hz BCV delivered to Fz (the midline of the forehead at the hairline), the cervical VEMP indicates predominantly saccular function and the ocular VEMP indicates predominantly utricular function. The neural, anatomical and behavioural evidence underpins clinical tests of otolith function in humans using sound and vibration.

Effect of stimulus rise-time on the ocular vestibular-evoked myogenic potential to bone-conducted vibration.

OBJECTIVES: The negative potential at 10 msec (called n10) of the ocular vestibular-evoked myogenic potential (oVEMP) recorded beneath the eyes in response to bone-conducted vibration (BCV) delivered to the skull at the midline in the hairline (Fz) is a new indicator of otolithic, and in particular utricular, function. Our aim is to find the optimum combination of frequency and rise-time for BCV stimulation, to improve the sensitivity of oVEMP testing in the clinic. DESIGN: We tested 10 healthy subjects with 6 msec tone bursts of BCV at three stimulus frequencies, 250, 500, and 750 Hz, at rise-times ranging between 0 and 2 msec. The BCV was delivered at Fz. RESULTS: The n10 response was significantly larger at the shorter rise-times, being largest at zero rise-time. In addition, we examined the effect of stimulus frequency in these same subjects by delivering 6 msec tone bursts at zero rise-time at a range of frequencies from 50 to 1200 Hz. The main effect of rise-time was significant with shorter rise-times leading to larger n10 responses and the Rise-Time × Frequency interaction was significant so that at low frequencies (100 Hz) shorter rise-times had a modest effect on n10 whereas at high frequencies (750 Hz) shorter rise-times increased n10 amplitude substantially. The main effect of frequency was also significant: The n10 response tended to be larger at lower frequency, being largest between 250 and 500 Hz. CONCLUSIONS: In summary, in this sample of healthy subjects, the most effective stimulus for eliciting oVEMP n10 to BCV at Fz was found to be a tone burst with a rise-time of 0 msec at low stimulus frequency (250 or 500 Hz).

Autonomous identification of freezing of gait in Parkinson's disease from lower-body segmental accelerometry.

BACKGROUND: We have previously published a technique for objective assessment of freezing of gait (FOG) in Parkinson's disease (PD) from a single shank-mounted accelerometer. Here we extend this approach to evaluate the optimal configuration of sensor placement and signal processing parameters using seven sensors attached to the lumbar back, thighs, shanks and feet. METHODS: Multi-segmental acceleration data was obtained from 25 PD patients performing 134 timed up and go tasks, and clinical assessment of FOG was performed by two experienced raters from video. Four metrics were used to compare objective and clinical measures; the intraclass correlation coefficient (ICC) for number of FOG episodes and the percent time frozen per trial; and the sensitivity and specificity of FOG detection. RESULTS: The seven-sensor configuration was the most robust, scoring highly on all measures of performance (ICC number of FOG 0.75; ICC percent time frozen 0.80; sensitivity 84.3%; specificity 78.4%). A simpler single-shank sensor approach provided similar ICC values and exhibited a high sensitivity to FOG events, but specificity was lower at 66.7%. Recordings from the lumbar sensor offered only moderate agreement with the clinical raters in terms of absolute number and duration of FOG events (likely due to musculoskeletal attenuation of lower-limb 'trembling' during FOG), but demonstrated a high sensitivity (86.2%) and specificity (82.4%) when considered as a binary test for the presence/absence of FOG within a single trial. CONCLUSIONS: The seven-sensor approach was the most accurate method for quantifying FOG, and is best suited to demanding research applications. A single shank sensor provided measures comparable to the seven-sensor approach but is relatively straightforward in execution, facilitating clinical use. A single lumbar sensor may provide a simple means of objective FOG detection given the ubiquitous nature of accelerometers in mobile telephones and other belt-worn devices.

A review of the geometrical basis and the principles underlying the use and interpretation of the video head impulse test (vHIT) in clinical vestibular testing.

This paper is concerned mainly with the assumptions underpinning the actual testing procedure, measurement, and interpretation of the video head impulse test-vHIT. Other papers have reported in detail the artifacts which can interfere with obtaining accurate eye movement results, but here we focus not on artifacts, but on the basic questions about the assumptions and geometrical considerations by which vHIT works. These matters are crucial in understanding and appropriately interpreting the results obtained, especially as vHIT is now being applied to central disorders. The interpretation of the eye velocity responses relies on thorough knowledge of the factors which can affect the response-for example the orientation of the goggles on the head, the head pitch, and the contribution of vertical canals to the horizontal canal response. We highlight some of these issues and point to future developments and improvements. The paper assumes knowledge of how vHIT testing is conducted.

Effects of Galvanic vestibular stimulation on cognitive function.

Although imaging studies suggest activation of cortical areas by vestibular input, there is little evidence of an adverse effect of non-veridical vestibular input on cognitive function. To test the hypothesis that degraded vestibular afferent input adversely affects cognition, we compared performance on a cognitive test battery in a group undergoing suprathreshold bilateral bipolar Galvanic vestibular stimulation (GVS) with a control group receiving no GVS or subthreshold stimulation. The battery consisted of six cognitive tests as follows: reaction time, dual tasking, Stroop, mental rotation, perspective-taking and matching-to-sample, as well as a simple visuomotor (manual tracking) task. Subjects performed the test battery before, during and after suprathreshold GVS exposure or subthreshold stimulation. Suprathreshold GVS significantly increased error rate for the match-to-sample and perspective-taking tasks relative to the subthreshold group, demonstrating a negative effect of non-veridical vestibular input in these specific cognitive tasks. Reaction time, dual tasking, mental rotation and manual tracking were unaffected by GVS exposure. The adverse effect of suprathreshold GVS on perspective taking but not mental rotation is consistent with imaging studies, which have demonstrated that egocentric mental transformations (perspective taking) occur primarily in cortical areas that receive vestibular input (the parietal-temporal junction and superior parietal lobule), whereas object-based transformations (mental rotation) occur in the frontoparietal region. The increased error rate during the match-to-sample task is likely due to interference with hippocampal processing related to spatial memory, as suggested by imaging studies on vestibular patients.

Gentamicin ototoxicity: a 23-year selected case series of 103 patients.

OBJECTIVE: To review patients with severe bilateral vestibular loss associated with gentamicin treatment in hospital. DESIGN AND SETTING: A retrospective case series of presentations to a balance disorders clinic between 1988 and 2010. MAIN OUTCOME MEASURES: Relationship between vestibulotoxicity and gentamicin dose or dosing profile; indications for prescribing gentamicin. RESULTS: 103 patients (age, 18-84 years; mean, 64 years) presented with imbalance, oscillopsia or both, but none had vertigo. Only three noted some hearing impairment after having gentamicin, but audiometric thresholds for all patients were consistent with their age. In all patients, the following tests gave positive results: a bilateral clinical head-impulse test, a vertical head-shaking test for vertical oscillopsia, and a foam Romberg test. In 21 patients, imbalance occurred during gentamicin treatment (ignored or dismissed by prescribers in 20) and in 66 after treatment; the remaining 16 could not recall when symptoms were first noticed, except that it was after gentamicin treatment in hospital. Total gentamicin dose range was 2-318 mg/kg (mean, 52 mg/kg), daily dose range was 1.5-5.6 mg/kg (mean, 3.5mg/kg), and duration was 1-80 days (mean, 17 days). Six patients had only a single dose; 26 had five or fewer doses. Serum gentamicin levels, measured in 82 patients, were in the recommended range in 59. Time to diagnosis ranged from 4 days to 15 years. Nephrotoxicity developed in 43 patients. Gentamicin dosage complied with contemporary or current Australian antibiotic guidelines in under half the patients. CONCLUSIONS: Gentamicin ototoxicity is vestibular, not cochlear, producing permanent loss of balance, but not of hearing. Gentamicin can be vestibulotoxic in any dose, in any regimen, at any serum level.

Vestibular semicircular canal function as detected by video Head Impulse Test (vHIT) is essentially unchanged in people with Parkinson's disease compared to healthy controls.

BACKGROUND: Parkinson's disease (PD) is a common multi-system neurodegenerative disorder with possible vestibular system dysfunction, but prior vestibular function test findings are equivocal. OBJECTIVE: To report and compare vestibulo-ocular reflex (VOR) gain as measured by the video head impulse test (vHIT) in participants with PD, including tremor dominant and postural instability/gait dysfunction phenotypes, with healthy controls (HC). METHODS: Forty participants with PD and 40 age- and gender-matched HC had their vestibular function assessed. Lateral and vertical semicircular canal VOR gains were measured with vHIT. VOR canal gains between PD participants and HC were compared with independent samples t-tests. Two distinct PD phenotypes were compared to HC using Tukey's ANOVA. The relationship of VOR gain with PD duration, phenotype, severity and age were investigated using logistic regression. RESULTS: There were no significant differences between groups in vHIT VOR gain for lateral or vertical canals. There was no evidence of an effect of PD severity, phenotype or age on VOR gains in the PD group. CONCLUSION: The impulsive angular VOR pathways are not significantly affected by the pathophysiological changes associated with mild to moderate PD.

Validation of 24-hour ambulatory gait assessment in Parkinson's disease with simultaneous video observation.

BACKGROUND: Parkinson's disease (PD) is a neurodegenerative disorder resulting in motor disturbances that can impact normal gait. Although PD initially responds well to pharmacological treatment, as the disease progresses efficacy often fluctuates over the course of the day, and clinical management would benefit from long-term objective measures of gait. We have previously described a small device worn on the shank that uses acceleration and angular velocity sensors to calculate stride length and identify freezing of gait in PD patients. In this study we extend validation of the gait monitor to 24-h using simultaneous video observation of PD patients. METHODS: A sleep laboratory was adapted to perform 24-hr video monitoring of patients while wearing the device. Continuous video monitoring of a sleep lab, hallway, kitchen and conference room was performed using a 4-camera security system and recorded to hard disk. Subjects (3) wore the gait monitor on the left shank (just above the ankle) for a 24-h period beginning around 5 pm in the evening. Accuracy of stride length measures were assessed at the beginning and end of the 24-h epoch. Two independent observers rated the video logs to identify when subjects were walking or lying down. RESULTS: The mean error in stride length at the start of recording was 0.05 m (SD 0) and at the conclusion of the 24 h epoch was 0.06 m (SD 0.026). There was full agreement between observer coding of the video logs and the output from the gait monitor software; that is, for every video observation of the subject walking there was a corresponding pulse in the monitor data that indicated gait. CONCLUSIONS: The accuracy of ambulatory stride length measurement was maintained over the 24-h period, and there was 100% agreement between the autonomous detection of locomotion by the gait monitor and video observation.

Galvanic vestibular stimulation as an analogue of spatial disorientation after spaceflight.

BACKGROUND: Exposure to microgravity adversely affects performance of astronaut pilots; a review of the first 100 Shuttle missions found that touchdown speed was above specified limits in 20% of landings, in contrast to near ideal performance in preflight high-fidelity Shuttle simulations. Ground-based simulators emphasize spacecraft handling abilities, but do not recreate the effects of extended weightlessness on sensorimotor function. The aim of this study was to validate an analogue of the sensorimotor effects of microgravity using pseudorandom bilateral bipolar galvanic vestibular stimulation (GVS) during Shuttle landing simulations. METHODS: Pilot performance was assessed during simulated Shuttle landings in the Vertical Motion Simulator at NASA Ames Research Center, Moffett Field, CA (used for astronaut pilot training). Subjects (N = 11) flew eight pairs of identical landing profiles (final approach and touchdown), with and without GVS, presented in a pseudorandom order. RESULTS: Touchdown speed was on target (204 kn) without GVS [203.8 kn], but increased significantly during GVS exposure 1208.5 kn] and was at the upper limit (209 kn) of the target range. The adverse effects of GVS on pilot performance were obvious. Unsuccessful (crash) landings increased from 2.3% (2/88) without GVS to 9% (7/88) with GVS. Hard landings, with touchdown speed in the 'red' (unacceptable) range (> 214 kn), almost doubled from 14 (15.9%) without GVS to 27 (30.7%) with GVS. CONCLUSION: GVS was an effective analogue of decrements in postflight Shuttle pilot performance.

Tolerance to extended galvanic vestibular stimulation: optimal exposure for astronaut training.

BACKGROUND: We have developed an analogue of postflight sensorimotor dysfunction in astronauts using pseudorandom galvanic vestibular stimulation (GVS). To date there has been no study of the effects of extended GVS on human subjects and our aim was to determine optimal exposure for astronaut training based on tolerance to intermittent and continuous galvanic stimulation. METHODS: There were 60 subjects who were exposed to a total of 10.5 min of intermittent GVS at a peak current of 3.5 mA or 5 mA. A subset of 24 subjects who tolerated the intermittent stimulus were subsequently exposed to 20-min continuous stimulation at 3.5 mA or 5 mA. RESULTS: During intermittent GVS the large majority of subjects (78.3%) reported no or at most mild motion sickness symptoms, 13.3% reported moderate symptoms, and 8.3% experienced severe nausea and requested termination of the stimulus. During 20-min continuous exposure, 83.3% of subjects reported no or at most mild motion sickness symptoms and 16.7% (all in the 5-mA group) experienced severe nausea. CONCLUSION: Based on these results, we propose two basic modes of GVS application to minimize the incidence of motion sickness: intermittent high (5 mA) amplitude, suited to simulation of intensive operator tasks requiring a high-fidelity analogue of postflight sensorimotor dysfunction such as landing or docking maneuvers; and continuous low (3.5 mA) amplitude stimulation, for longer simulation scenarios such as extra vehicular activity. Our results suggest that neither mode of stimulation would induce motion sickness in the large majority of subjects for up to 20 min exposure.

Video-head impulse test in superior canal dehiscence.

BACKGROUND: Superior Canal Dehiscence is classically diagnosed with typical abnormalities on Vestibular Evoked Myogenic Potentials (VEMPs) and Computed Tomography (CT) scans. AIM: This paper discusses the utility of the video Head Impulse Test (vHIT) in SCD. METHODS: Data from 11 ears (8 patients) with SCD were retrospectively reviewed. Results from vHIT, VEMPs and CT and when possible, MRI scans were correlated. An audit of 300 vHIT from patients undergoing routine testing for any neurotological complaint was also conducted to look at the incidence of isolated abnormal superior canal function. RESULTS: 82% of patients (9 ears) with SCD showed abnormal vHIT (reduced gain and catch-up saccades) isolated to the affected superior semicircular canal. CONCLUSION: Correlation of the CT and VEMPs are important in forming a diagnosis of SCD. However, if isolated superior canal vHIT abnormalities are demonstrated, it is suggestive of SCD and such patients should be referred for further investigations.

A Video Self-Modeling Intervention Using Virtual Reality Plus Physical Practice for Freezing of Gait in Parkinson Disease: Feasibility and Acceptability Study.

BACKGROUND: Despite optimal medical and surgical intervention, freezing of gait commonly occurs in people with Parkinson disease. Action observation via video self-modeling, combined with physical practice, has potential as a noninvasive intervention to reduce freezing of gait. OBJECTIVE: The aim of this study is to determine the feasibility and acceptability of a home-based, personalized video self-modeling intervention delivered via a virtual reality head-mounted display (HMD) to reduce freezing of gait in people with Parkinson disease. The secondary aim is to investigate the potential effect of this intervention on freezing of gait, mobility, and anxiety. METHODS: The study was a single-group pre-post mixed methods pilot trial for which 10 participants with Parkinson disease and freezing of gait were recruited. A physiotherapist assessed the participants in their homes to identify person-specific triggers of freezing and developed individualized movement strategies to overcome freezing of gait. 180° videos of the participants successfully performing their movement strategies were created. Participants watched their videos using a virtual reality HMD, followed by physical practice of their strategies in their own homes over a 6-week intervention period. The primary outcome measures included the feasibility and acceptability of the intervention. Secondary outcome measures included freezing of gait physical tests and questionnaires, including the Timed Up and Go Test, 10-meter walk test, Goal Attainment Scale, and Parkinson Anxiety Scale. RESULTS: The recruitment rate was 24% (10/42), and the retention rate was 90% (9/10). Adherence to the intervention was high, with participants completing a mean of 84% (SD 49%) for the prescribed video viewing and a mean of 100% (SD 56%) for the prescribed physical practice. One participant used the virtual reality HMD for 1 week and completed the rest of the intervention using a flat-screen device because of a gradual worsening of his motion sickness. No other adverse events occurred during the intervention or assessment. Most of the participants found using the HMD to view their videos interesting and enjoyable and would choose to use this intervention to manage their freezing of gait in the future. Five themes were constructed from the interview data: reflections when seeing myself, my experience of using the virtual reality system, the role of the virtual reality system in supporting my learning, developing a deeper understanding of how to manage my freezing of gait, and the impact of the intervention on my daily activities. Overall, there were minimal changes to the freezing of gait, mobility, or anxiety measures from baseline to postintervention, although there was substantial variability between participants. The intervention showed potential in reducing anxiety in participants with high levels of anxiety. CONCLUSIONS: Video self-modeling using an immersive virtual reality HMD plus physical practice of personalized movement strategies is a feasible and acceptable method of addressing freezing of gait in people with Parkinson disease.

Effects of head-down bed rest and artificial gravity on spatial orientation.

We studied spatial orientation before and after 21 days of 6 degrees head-down bed rest in 15 subjects. During bed rest, 8 subjects were treated daily with 1 h Gz centrifugation (artificial gravity) (2.5 g at the feet; 1.0 g at the heart), with 7 subjects serving as controls. Ocular counter-rolling and subjective visual vertical were assessed during 90 degrees whole body roll tilt to the left and right. Ocular counter-rolling was unaffected by bed rest and bed rest + artificial gravity. Performance on the subjective visual vertical task was unchanged in the control group, but exhibited a significant increase in error for 48 h after bed rest in the treatment (artificial gravity) group. Intermittent application of linear acceleration along the long body axis may have increased the weighting of the idiotropic vector, resulting in an increased bias of the subjective visual vertical toward the long body axis during 90 degrees roll tilt.

Law and (rec)order: Updating memory for criminal events with body-worn cameras.

Body-worn video is increasingly relied upon in the criminal justice system, however it is unclear how viewing chest-mounted video may affect a police officer's statement about an event. In the present study, we asked whether reviewing footage from an experienced event could shape an individual's statement, and if so, whether reporting before reviewing may preserve an officer's original experience. Student participants (n = 97) were equipped with chest-mounted cameras as they viewed a simulated theft in virtual reality. One week later, half of the participants recalled the event in an initial statement while the other half did not. Participants then viewed either their body-worn video or a control video. Finally, participants provided their statement (no initial statement condition) or were given the opportunity to amend their original account (initial statement condition). Results revealed that viewing body-worn video enhanced the completeness and accuracy of individuals' free recall statements. However, whilst reviewing footage enabled individuals to exclude errors they had written in their initial statements, they also excluded true details that were uncorroborated by the camera footage (i.e., details which individuals experienced, but that their camera did not record). Such camera conformity is discussed in light of the debate on when an officer should access their body-worn video during an investigation and the influence of post-event information on memory.

The Potential Benefits of Personalized 360 Video Experiences on Affect: A Proof-of-Concept Study.

Despite the importance of healthy affect to improving hospital outcomes, effective means of promoting healthy affect have yet to be elucidated. One unexplored solution lies with virtual reality (VR) technologies. The present study sought to investigate whether personalized VR interventions could improve affect levels in a university sample (n = 33) and one hospitalized patient depending upon one's baseline affective profile. Positive and Negative Affect Schedule scores were compared before and after witnessing important life events/environments in VR and interview responses were analyzed. Within the university student sample, those with high affective profiles produced significantly greater post/pre negative affect (NA) score decreases than self-fulfilling and low affective profiles. The patient experienced a 10-point increase in positive affect and a 7-point decrease in NA. Overall, the current study tended to demonstrate the acceptability and efficacy of personalized VR experiences in promoting healthy affect.

Virtual Reality for Teletherapy: Avatars May Combine the Benefits of Face-to-Face Communication with the Anonymity of Online Text-Based Communication.

Self-disclosure is an essential component of social communication that has been associated with trust, liking, and ultimately strong relationships. As technology continues to develop, so do the number of methods to create and maintain relationships. While speaking face-to-face (FtF) remains the primary way to communicate, computer-mediated communication has become more common, meaning that research into self-disclosure has expanded to new domains, including virtual reality (VR). This study compared self-disclosure between three conversation contexts: FtF, online text-based (OTB) communication, or VR. Zero-contact dyads comprised female university students who completed 20-minute conversations guided by one of two discussion prompts: the closeness-generating or small talk procedure. These prompts were designed to either increase or not increase self-disclosure. These conversations were recorded and coded for the frequency of total, factual, cognitive, and emotional self-disclosures as objective measures. Participants' perceptions of personal and partner's self-disclosures were also assessed by questionnaires as perceived measures. FtF and VR conditions exceeded OTB communication in perceived and objective measures of self-disclosure. Although no significant differences emerged between FtF and VR conditions for factual or perceived self-disclosure, participants in the FtF condition had more total, cognitive, and emotional self-disclosures than VR conditions. Implications for communication and teletherapy are discussed. The present study offers preliminary evidence that VR could potentially rival FtF as a communication medium and be as effective in facilitating self-disclosure. Findings offer a starting point for research on social applications of VR.