## 2 Materials and Methods  
### Data Gathering Outlines  
To evaluate the fundamental ADLs essential in the subacute stroke care period [4, 5, 6, 15], seven gestures were selected: rest, hand fist movement (i.e., clenched fist), wrist flexion, wrist extension, fingers opening or spread hand, and two fine movements--index pinch and thumbs up (i.e., upright thumb). The selection of these sets of gestures is justified for several important reasons. First, the resting state was included as a baseline gesture class, as it can provide a comparison for distinguishing the state before and after an intended movement [15,27]. This is particularly important when considering stroke-induced impairments at rest, such as tremors and abnormal muscle synergies, which may result in unintentional movements and complicate the decoding of intended distal hand motions [5,14]. A clenched fist is essential for gripping objects and is one of the fundamental ADLs (e.g., holding a toothbrush). It reflects the functioning of the hand, including both intrinsic muscles and extrinsic muscles, as well as the wrist and forearm, serving as a comprehensive metric of upper limb interconnection [28]. Additionally, a persistent clenched fist is a common early sign of developing upper extremity spasticity and should be addressed for both diagnostic and rehabilitation purposes [29]. Wrist flexion was selected as a key motor movement to assess motor control involving superficial forearm flexors, providing insight into the degree and pattern of post-stroke neuromuscular changes [15]. At the same time, wrist extension, a key component for proper hand positioning during grasping movements, was selected as a discriminative gesture class compared to wrist flexion. This selection is due to the involvement of large superficial forearm muscles, which are accessible via surface EMG electrodes, enhancing the diversity of the suggested hand gestures in stroke patients [13]. The fingers opening (spread hand) gesture was selected to evaluate the function of intrinsic hand muscles, providing insight into a distinct set of hand muscle capabilities compared to gestures that rely heavily on long flexors or involve pinching and gripping [28]. Assessing intrinsic muscle performance is crucial for monitoring and rehabilitating hand paresis, given its importance for fine motor control and tasks required for ADLs, as forearm performance regains more than fine hand movements after a stroke [30]. The index pinch, as a precise, task-oriented gesture, was chosen because it requires a high-precision grip and fine finger movements, and is critical for hand ADLs (e.g., buttoning clothes or using a phone) [29]. Failure to perform this gesture indicates significant limitations in independence and function. Moreover, the index pinch movement is associated with specific metrics which assess hand function and monitor recovery progress post-stroke [5; 31]. The upright thumb gesture was chosen because of the thumb's unique opposable structure, which is crucial for nearly half of the hand ADLs [28; 29; 31]. Performing this gesture involves specific hand muscles (extensor pollicis longus, extensor pollicis brevis, and abductor pollicis longus) and forearm muscles (e.g., extensor carpi radialis longus). This essential fine motor movement indicates motor impairment after a stroke and serves as a rehabilitation target, reflecting the thumb's critical role in gripping and pinching and its inclusion in the Fugl-Meyer Assessment for Upper Extremity (FMA-UE) [5]. Despite the need for extensive research into numerous useful gestures beyond this selection, no additional gestures were studied, as post-stroke patients with a moderate-to-severe status in hospital settings are often medically fragile and face significant physical and cognitive challenges [3; 5]. Including unnecessary measurements could be distressing and tiring and could interfere with essential medical care and recovery.