The Dutch Oxford Cognitive Screen (OCS-NL): psychometric properties in Flemish stroke survivors.

BACKGROUND AND PURPOSE: The Oxford Cognitive Screen is a stroke-specific screen to evaluate attention, executive functions, memory, praxis, language, and numeric cognition. It was originally validated in England for acute stroke patients. In this study, we examined the psychometric properties of the Dutch OCS (OCS-NL). METHODS: A total of 193 (99 acute stroke unit, 94 rehabilitation unit) patients were included in our study. A subset of patients (n = 128) completed a retest with the parallel version of the OCS-NL. RESULTS: First, we did not find evidence for a difference in prevalence of impairment between patients in the acute stroke versus rehabilitation unit on all but one of the subtests. For praxis, we observed a 14% lower prevalence of impairment in the rehabilitation than the acute stroke unit. Second, the parallel-form reliability ranged from weak to excellent across subtests. Third, in stroke patients below age 60, the OCS-NL had a 92% sensitivity relative to the MoCA, while the MoCA had a 55% sensitivity relative to the OCS-NL. Last, although left-hemispheric stroke patients performed worse on almost all MoCA subdomains, they performed similarly to right-hemispheric stroke patients on non-language domains on the OCS-NL. CONCLUSIONS: Our results suggest that the OCS-NL is a reliable cognitive screen that can be used in acute stroke and rehabilitation units. The OCS-NL may be more sensitive to detect cognitive impairment in young stroke patients and less likely to underestimate cognitive abilities in left-hemispheric stroke patients than the MoCA.

An immersive virtual reality game to train spatial attention orientation after stroke: A feasibility study.

Immersive virtual reality (IVR) may boost neglect recovery, as it can provide an engaging experience in a 3D environment. We designed an IVR rehabilitation game for neglect patients using the Oculus Rift. Multisensory cues were presented in the neglected visual field in a patient-tailored way. We acquired pilot data in 15 neurologically healthy controls and 7 stroke patients. First, we compared cybersickness before and after VR exposure. Second, we assessed the user experience through a questionnaire. Third, we tested whether neglect symptoms corresponded between the VR game and a computerized cancelation task. Fourth, we evaluated the effect of the multisensory cueing on target discrimination. Last, we tested two algorithms to tailor the game to the characteristics of the neglected visual field. Cybersickness significantly reduced after VR exposure in six stroke patients and was low in healthy controls. Patients rated the user experience neutral to positive. In addition, neglect symptoms were consistent between a computerized cancelation and VR rehabilitation task. The multisensory cue positively affected target discrimination in the game and we successfully presented sensory stimulation to the neglected visual field in a patient-tailored way. Our results show that it is promising to use gamified patient-tailored immersive VR for neglect rehabilitation.

The Dutch version of the Oxford Cognitive Screen (OCS-NL): normative data and their association with age and socio-economic status.

The Oxford Cognitive Screen (OCS) is a screening tool designed for stroke patients, assessing attention, executive functions, language, praxis, numeric cognition and memory. Here we present norms for the two parallel versions of the Dutch OCS (OCS-NL, acquired in 246 participants for version A and a subset of 179 participants for version B. We evaluated the association of age and socio-economic status (i.e. education, income, occupation) with OCS-NL performance There were no systematic performance differences between income groups, nor between manual and non-manual workers. There were small differences between education groups. The association of education and performance did not vary across subtests. The association of age and performance varied across subtests, with the strongest associations for the naming, praxis, verbal memory and executive task. Thus, OCS-NL norms do not need to be stratified on income and occupation and age-specific norms are recommended for some subtests.

Acceptance of immersive head-mounted virtual reality in older adults.

Immersive virtual reality has become increasingly popular to improve the assessment and treatment of health problems. This rising popularity is likely to be facilitated by the availability of affordable headsets that deliver high quality immersive experiences. As many health problems are more prevalent in older adults, who are less technology experienced, it is important to know whether they are willing to use immersive virtual reality. In this study, we assessed the initial attitude towards head-mounted immersive virtual reality in 76 older adults who had never used virtual reality before. Furthermore, we assessed changes in attitude as well as self-reported cybersickness after a first exposure to immersive virtual reality relative to exposure to time-lapse videos. Attitudes towards immersive virtual reality changed from neutral to positive after a first exposure to immersive virtual reality, but not after exposure to time-lapse videos. Moreover, self-reported cybersickness was minimal and had no association with exposure to immersive virtual reality. These results imply that the contribution of VR applications to health in older adults will neither be hindered by negative attitudes nor by cybersickness.

EEG frequency tagging reveals higher order intermodulation components as neural markers of learned holistic shape representations.

Shape perception is intrinsically holistic: combinations of features give rise to configurations with emergent properties that are different from the sum of the parts. The current study investigated neural markers of holistic shape representations learned by means of categorization training. We used the EEG frequency tagging technique, where two parts of a shape stimulus were 'tagged' by modifying their contrast at different temporal frequencies. Signals from both parts are integrated and, as a result, emergent frequency components (so-called, intermodulation responses, IMs), caused by nonlinear interaction of two frequency signals, are observed in the EEG spectrum. First, participants were trained in 4 sessions to discriminate highly similar, unfamiliar shapes into two categories, defined based on the combination of features. After training, EEG was recorded while frequency-tagged shapes from either the trained or the untrained shape family were presented. For all IMs combined, no learning effects were detected, but post hoc analyses of higher-order IMs revealed stronger occipital and occipito-temporal IMs for both trained and untrained exemplars of the trained shape family as compared to the untrained shape family. In line with recent findings, we suggest that the higher-order IMs may reflect high-level visual computations, like holistic shape categorization, resulting from a cascade of non-linear operations. Higher order frequency responses are relatively low in power, hence results should be interpreted cautiously and future research is needed to confirm these effects. In general, these findings are, to our knowledge, the first to show IMs as a neural correlate of perceptual learning.