Interdependences between finger movement direction and haptic perception of oriented textures

Humans flexibly use visual priors to optimize their haptic exploratory behavior

Humans can use prior information to optimize their haptic exploratory behavior. Here, we investigated the usage of visual priors, which mechanisms enable their usage, and how the usage is affected by information quality. Participants explored different grating textures and discriminated their spatial frequency. Visual priors on texture orientation were given each trial, with qualities randomly varying from high to no informational value. Adjustments of initial exploratory movement direction orthogonal to the textures' orientation served as an indicator of prior usage. Participants indeed used visual priors; the more so the higher the priors' quality (Experiment 1). Higher task demands did not increase the direct usage of visual priors (Experiment 2), but possibly fostered the establishment of adjustment behavior. In Experiment 3, we decreased the proportion of high-quality priors presented during the session, hereby reducing the contingency between high-quality priors and haptic information. In consequence, even priors of high quality ceased to evoke movement adjustments. We conclude that the establishment of adjustment behavior results from a rather implicit contingency learning. Overall, it became evident that humans can autonomously learn to use rather abstract visual priors to optimize haptic exploration, with the learning process and direct usage substantially depending on the priors' quality.

Masking interferes with haptic texture perception from sequential exploratory movements

Haptic texture perception is based on sensory information sequentially gathered during several lateral movements ("strokes"). In this process, sensory information of earlier strokes must be preserved in a memory system. We investigated whether this system may be a haptic sensory memory. In the first experiment, participants performed three strokes across each of two textures in a frequency discrimination task. Between the strokes over the first texture, participants explored an intermediate area, which presented either a mask (high-energy tactile pattern) or minimal stimulation (low-energy smooth surface). Perceptual precision was significantly lower with the mask compared with a three-strokes control condition without an intermediate area, approaching performance in a one-stroke-control condition. In contrast, precision in the minimal stimulation condition was significantly better than in the one-stroke control condition and similar to the three-strokes control condition. In a second experiment, we varied the number of strokes across the first stimulus (one, three, five, or seven strokes) and either presented no masking or repeated masking after each stroke. Again, masking between the strokes decreased perceptual precision relative to the control conditions without masking. Precision effects of masking over different numbers of strokes were fit by a proven model on haptic serial integration (Lezkan & Drewing, Attention, Perception, & Psychophysics 80(1): 177-192, 2018b) that modeled masking by repeated disturbances in the ongoing integration. Taken together, results suggest that masking impedes the processes of haptic information preservation and integration. We conclude that a haptic sensory memory, which is comparable to iconic memory in vision, is used for integrating sequentially gathered sensory information.

Nursing effects of finger exercise on cognitive function and others for cerebral ischemic stroke patients

OBJECTIVE

To investigate the nursing effects of finger exercise training on cognitive function and others for patients with cerebral ischemic stroke (CIS).

METHODS

A total of 200 patients with CIS were selected in this prospective study. According to the random number table method, they were divided into control group (n=100, routine nursing) and research group (n=100, routine nursing combined with finger exercise training). Various scales were used to evaluate the cognitive function, hand function, upper limb motor function, wrist flexor muscle tone, degree of neurological impairment and ability of daily living (ADL) in the two groups before and after intervention. And the incidence of mild vascular cognitive impairment (VCI) after intervention was compared.

RESULTS

After intervention, Montreal Cognitive Assessment (MoCA), Mini Mental State Examination (MMSE), hand function, Fugl-meyer Assessment (FMA) and ADL scores in both groups were significantly increased, and those in the research group were significantly higher than those in the control group (all P<0.05). There were opposite trends in the Neurologic Functional Defect (NIHSS) and Modified Ashworth Scale (MAS) for wrist flexor scores (all P<0.05). The incidence of mild VCI in the research group was significantly lower than that in the control group (P<0.05).

CONCLUSION

On the basis of early rehabilitation nursing, combined finger exercise training can improve cognitive function, hand function, upper limb function and ADL for patients with CIS.