Virtual Reality's Impact on Upper Limb Function in Post-stroke Patients

The Fugl-Meyer Assessment of the Upper Extremity (FMA-UE) covers all aspects of upper limb function, such as movement, coordination, and reflex actions of the shoulder, elbow, forearm, wrist, and hand, with a total of 33 assessment items. Patients were assessed according to a specific scale with a total score of 66, with higher scores indicating better recovery of upper limb function.

The sense of ownership (SOO) questionnair investigates a number of aspects including sense of body ownership, sense of position in the real or virtual hand, haptic experience, body similarity, and body transformation. Scores are allocated on a 7-point Likert scale, from "Strongly disagree (-3 points)" to "Strongly agree (3 points)", depending on how much the patient agrees with each statement. The mean score of all questions is calculated as the final SOO questionnaire score, and the higher the score, the stronger the SOO.

We asked patients to report where they thought their affected hand was by pointing with their other hand or describing it verbally and compared this with the position of the affected hand they initially felt to calculate the offset distance, thereby measuring the degree of proprioceptive error.

The Action Research Arm Test (ARAT) consists of 19 evaluated tasks bifurcated into four subscales: grasping, gripping, pinching, and gross motor skills. The total score ranges from 0 and 57, with higher scores representing better function.

The scale covers the level of consciousness, extraocular movements, visual fields, facial muscle function, limb strength, sensory function, coordination (ataxia), speech (aphasia), language (dysarthria), and lateralized inattention (neglect). The scoring spectrum extends from 0 to 42 points, with the higher the score, the more severe neurologic damage.

The Mini-Mental State Examination scale(MMSE) is mainly used to quickly assess cognitive areas such as memory, orientation, attention, calculation, language ability, and visual-spatial ability. The scale contains 30 questions with a total score range of 0-30 points. The higher the total score, the better the cognitive function. The normal threshold is divided according to the educational level (for example, those with junior high school education or above need to score ≥24 points).

Electrodes were placed on the key muscle groups of the hemiplegic upper limb according to the Surface EMG for the Non-Invasive Assessment of Muscles guidelines. In addition to the biceps and triceps brachii muscles of the upper arm, eight electrodes were placed evenly at the maximal circumference of the forearm cross-section, in which the electrodes were distributed on the centerlines of the anterior, ulnar, posterior, and radial sides of the forearm. Before placing the electrodes, the skin surface was cleaned with alcohol and the sampling rate was set to 1000 Hz. subjects were asked to perform 11 simple normative upper limb functional tasks, which were designed by Li et al. based on the FMA-UE scale . The sEMG signals were recorded during the performance of the tasks, which were repeated three times with at least 30 seconds of rest between each trial.

The subjects were seated comfortably and asked to close their eyes, wake up, relax, and be quiet for 5 minutes. The recording electrodes were placed on the scalp according to the international 10/20 system, with the Cz electrode of the head as the reference. The impedance of each channel was ensured to be below 5k Ω and the sampling frequency was 1k Hz. EEG will be used to assess changes in brain activity by analyzing the power distribution across different frequency bands (delta, theta, alpha, beta), event-related potentials (ERPs) in response to motor tasks or stimuli, and the coherence between brain regions to evaluate motor network synchronization.

The subjects were asked to remain still and provided with earplugs to alleviate discomfort from scanning noise. Functional images were acquired using an echo-planar imaging (EPI_BOLD) sequence with scanning parameters as follows: repetition time = 3000 ms, echo time = 30 ms, flip angle = 90 degrees, field of view = 220 × 220 mm, matrix size = 64 × 64, layer thickness = 3 mm layer position = 43, and a total of 240 time points being captured over a scanning period of 12 minutes.