Eye movements reveal a similar positivity effect in Chinese and UK older adults.

The "positivity effect" (PE) reflects an age-related increase in the preference for positive over negative information in attention and memory. The present experiment investigated whether Chinese and UK participants produce a similar PE. In one experiment, we presented pleasant, unpleasant, and neutral pictures simultaneously and participants decided which picture they liked or disliked on a third of trials, respectively. We recorded participants' eye movements during this task and compared time looking at, and memory for, pictures. The results suggest that older but not younger adults from both China and UK participant groups showed a preference to focus on and remember pleasant pictures, providing evidence of a PE in both cultures. Bayes Factor analysis supported these observations. These findings are consistent with the view that older people preferentially focus on positive emotional information, and that this effect is observed cross-culturally.

Factors affecting rehabilitation and use of upper limb after stroke: views from healthcare professionals and stroke survivors.

BACKGROUND: Training of the upper limb (UL) is limited in stroke rehabilitation, and about 50% of stroke survivors do not regain useful function in their upper limb. OBJECTIVES: This study explored what factors affect rehabilitation and use of upper limb after stroke from a stroke survivor and healthcare professional perspective to better understand low engagement in UL rehabilitation in the chronic stages of stroke. METHOD: Eight chronic stroke survivors and 21 healthcare professionals took part in semi-structured interviews or in one of three focus groups, respectively. RESULTS: Thematic analysis revealed three main themes: Availability of resources, Healthcare professional-patient relationship, and Psychosocial factors. Availability of resources and Healthcare professional-patient relationship indicated that due to resource pressures and a lack of communication and education, positive upper limb rehabilitation behaviors (e.g. engaging and integrating the upper limb in daily activity) were not always established in the early stages post-stroke. Psychosocial factors illustrated the cognitive and psychological barriers to sustained engagement with upper limb rehabilitation. CONCLUSION: The findings indicate that stroke survivors and healthcare professionals have very similar understandings of barriers to UL activity, and positive upper limb rehabilitation behaviors are not always established early in recovery post-stroke. Increased resources and healthcare professional-patient relationships seem key factors to establishing positive perceptions of UL rehabilitation. Addressing psychosocial issues and resource limitations may help sustain engagement with UL rehabilitation.

Upper limb and eye movement coordination during reaching tasks in people with stroke.

PURPOSE: To enhance understanding of the relationship between upper limb and eye movements during reaching tasks in people with stroke. METHODS: Eye movements were recorded from 10 control participants and 8 chronic stroke participants during a visual orienting task (Experiment 1) and a series of reaching tasks (Experiment 2). Stroke participants completed the reaching tasks using (i) their less impaired upper limb, (ii) their more impaired upper limb without support, and (iii) their more impaired upper limb, with support (SaeboMAS gravitational support and/or electrical stimulation). Participants were tested individually and completed both experiments in the same session. RESULTS: Oculomotor control and the coordination between the upper limb and the oculomotor system were found to be intact in stroke participants when no limb movements were required, or when the less impaired upper limb was used. However, when the more impaired upper limb was used, success and accuracy in reaching decreased and patterns of eye movements changed, with an observed increase in eye movements to the limb itself. With upper limb support, patterns of hand-eye coordination were found to more closely resemble those of the control group. CONCLUSION: Deficits in upper limb motor systems result in changes in patterns of eye movement behavior during reaching tasks. These changes in eye movement behavior can be modulated by providing upper limb support. Implications for Rehabilitation Deficits in upper limb motor systems can result in changes in patterns of eye movement behavior during reaching tasks. Upper limb support can reduce deficits in hand-eye coordination. Stroke rehabilitation outcomes should consider motor and oculomotor performance.

Attention and eye-movement control in reading: The selective reading paradigm.

We introduced a novel paradigm for investigating covert attention and eye-movement control in reading. In 2 experiments, participants read sentence words (shown in blue color) while ignoring interleaved distractor strings (shown in orange color). Each single-line text display contained a target word and a critical distractor. Critical distractors were located just prior to the target in the text and were either words or symbol strings (e.g., @#%&). Target word availability for parafoveal processing (i.e., preview validity) was also manipulated. The results indicated much shallower processing of distractors than targets, and this pattern was more pronounced for symbol than word distractors. The influences of word frequency and fixation location on first-pass fixation durations on distractors were dramatically different than the well-documented pattern obtained in normal reading. Robust preview benefits were demonstrated both when the critical distractors were fixated and when the critical distractors were skipped. Finally, with the exception of larger preview benefits that were obtained in the condition in which the target and critical distractor were identical, the magnitude of the preview effect was largely unaffected by the nature of the critical distractor. Implications of the present paradigm and findings to the study of eye-movement control in reading are discussed. (PsycINFO Database Record

The application of precisely controlled functional electrical stimulation to the shoulder, elbow and wrist for upper limb stroke rehabilitation: a feasibility study.

BACKGROUND: Functional electrical stimulation (FES) during repetitive practice of everyday tasks can facilitate recovery of upper limb function following stroke. Reduction in impairment is strongly associated with how closely FES assists performance, with advanced iterative learning control (ILC) technology providing precise upper-limb assistance. The aim of this study is to investigate the feasibility of extending ILC technology to control FES of three muscle groups in the upper limb to facilitate functional motor recovery post-stroke. METHODS: Five stroke participants with established hemiplegia undertook eighteen intervention sessions, each of one hour duration. During each session FES was applied to the anterior deltoid, triceps, and wrist/finger extensors to assist performance of functional tasks with real-objects, including closing a drawer and pressing a light switch. Advanced model-based ILC controllers used kinematic data from previous attempts at each task to update the FES applied to each muscle on the subsequent trial. This produced stimulation profiles that facilitated accurate completion of each task while encouraging voluntary effort by the participant. Kinematic data were collected using a Microsoft Kinect, and mechanical arm support was provided by a SaeboMAS. Participants completed Fugl-Meyer and Action Research Arm Test clinical assessments pre- and post-intervention, as well as FES-unassisted tasks during each intervention session. RESULTS: Fugl-Meyer and Action Research Arm Test scores both significantly improved from pre- to post-intervention by 4.4 points. Improvements were also found in FES-unassisted performance, and the amount of arm support required to successfully perform the tasks was reduced. CONCLUSIONS: This feasibility study indicates that technology comprising low-cost hardware fused with advanced FES controllers accurately assists upper limb movement and may reduce upper limb impairments following stroke.

Functional electrical stimulation mediated by iterative learning control and 3D robotics reduces motor impairment in chronic stroke.

BACKGROUND: Novel stroke rehabilitation techniques that employ electrical stimulation (ES) and robotic technologies are effective in reducing upper limb impairments. ES is most effective when it is applied to support the patients' voluntary effort; however, current systems fail to fully exploit this connection. This study builds on previous work using advanced ES controllers, and aims to investigate the feasibility of Stimulation Assistance through Iterative Learning (SAIL), a novel upper limb stroke rehabilitation system which utilises robotic support, ES, and voluntary effort. METHODS: Five hemiparetic, chronic stroke participants with impaired upper limb function attended 18, 1 hour intervention sessions. Participants completed virtual reality tracking tasks whereby they moved their impaired arm to follow a slowly moving sphere along a specified trajectory. To do this, the participants' arm was supported by a robot. ES, mediated by advanced iterative learning control (ILC) algorithms, was applied to the triceps and anterior deltoid muscles. Each movement was repeated 6 times and ILC adjusted the amount of stimulation applied on each trial to improve accuracy and maximise voluntary effort. Participants completed clinical assessments (Fugl-Meyer, Action Research Arm Test) at baseline and post-intervention, as well as unassisted tracking tasks at the beginning and end of each intervention session. Data were analysed using t-tests and linear regression. RESULTS: From baseline to post-intervention, Fugl-Meyer scores improved, assisted and unassisted tracking performance improved, and the amount of ES required to assist tracking reduced. CONCLUSIONS: The concept of minimising support from ES using ILC algorithms was demonstrated. The positive results are promising with respect to reducing upper limb impairments following stroke, however, a larger study is required to confirm this.

Using eye movement measures to investigate effects of age on memory for objects in a scene.

We examined whether there were age-related differences in eye movements during intentional encoding of a photographed scene that might account for age-related differences in memory of objects in the scene. Younger and older adults exhibited similar scan path patterns, and visited each region of interest in the scene with similar frequency and duration. Despite the similarity in viewing, there were fundamental differences in the viewing-memory relationship. Although overall recognition was poorer in the older than younger adults, there was no age effect on recognition probability for objects visited only once. More importantly, re-visits to objects brought gain in recognition probability for the younger adults, but not for the older adults. These results suggest that the age-related differences in object recognition performance are in part due to inefficient integration of information from working memory to longer-term memory.

Aging, eye movements, and object-location memory.

This study investigated whether "intentional" instructions could improve older adults' object memory and object-location memory about a scene by promoting object-oriented viewing. Eye movements of younger and older adults were recorded while they viewed a photograph depicting 12 household objects in a cubicle with or without the knowledge that memory about these objects and their locations would be tested (intentional vs. incidental encoding). After viewing, participants completed recognition and relocation tasks. Both instructions and age affected viewing behaviors and memory. Relative to incidental instructions, intentional instructions resulted in more accurate memory about object identity and object-location binding, but did not affect memory accuracy about overall positional configuration. More importantly, older adults exhibited more object-oriented viewing in the intentional than incidental condition, supporting the environmental support hypothesis.

Upper limb stroke rehabilitation: the effectiveness of Stimulation Assistance through Iterative Learning (SAIL).

A novel system has been developed which combines robotic therapy with electrical stimulation (ES) for upper limb stroke rehabilitation. This technology, termed SAIL: Stimulation Assistance through Iterative Learning, employs advanced model-based iterative learning control (ILC) algorithms to precisely assist participant's completion of 3D tracking tasks with their impaired arm. Data is reported from a preliminary study with unimpaired participants, and also from a single hemiparetic stroke participant with reduced upper limb function who has used the system in a clinical trial. All participants completed tasks which involved moving their (impaired) arm to follow an image of a slowing moving sphere along a trajectory. The participants' arm was supported by a robot and ES was applied to the triceps brachii and anterior deltoid muscles. During each task, the same tracking trajectory was repeated 6 times and ILC was used to compute the stimulation signals to be applied on the next iteration. Unimpaired participants took part in a single, one hour training session and the stroke participant undertook 18, 1 hour treatment sessions composed of tracking tasks varying in length, orientation and speed. The results reported describe changes in tracking ability and demonstrate feasibility of the SAIL system for upper limb rehabilitation.

Lateralisation of spatial processing and age.

Studies assessing spatial ability suggest right hemisphere specialisation for coordinate spatial processing and left hemisphere specialisation for categorical spatial processing. With regard to healthy ageing, spatial abilities may be affected selectively, with right hemisphere based coordinate processes being more vulnerable to age-related decline, but previous research has been inconsistent. In the present study, age and hemispheric specialisation of categorical and coordinate spatial abilities were explored. Testing 56 right-handed younger and older participants clearly showed a left hemisphere advantage for the categorical task and a right hemisphere advantage for the coordinate spatial task, for both age groups combined. Older adults were slower to process information and make a spatial judgement; nevertheless, the neural specialisation underlying spatial abilities seems to have remained consistent with age.