Quantitative assessment of hand function in healthy subjects and post-stroke patients with the action research arm test

Citation: Padilla-Magaña, J.F.; Peña-Pitarch, E.; Sánchez-Suarez, I.; Ticó-Falguera, N. Quantitative Assessment of Hand Function in Healthy Subjects and Post-Stroke Patients with the Action Research Arm Test. Sensors 2022,22, 3604. https://doi.org/10.3390/s22103604 Academic Editors: Cristina P. Santos and Joana Figueiredo Received: 30 March 2022 Accepted: 2 May 2022 Published: 10 May 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). sensors Article Quantitative Assessment of Hand Function in Healthy Subjects and Post-Stroke Patients with the Action Research Arm Test Jesus Fernando Padilla-Magaña 1,2,* , Esteban Peña-Pitarch 1, Isahi Sánchez-Suarez 2and Neus Ticó-Falguera 3 1Escola Politècnica Superior d’Enginyeria de Manresa (EPSEM), Polytechnic University of Catalonia (UPC), 08242 Manresa, Spain; [email protected] 2Department of Manufacturing Technologies, Polytechnic University of Uruapan Michoacán, Uruapan 60210, Michoacán, Mexico; [email protected] 3Physical Medicine and Rehabilitation Service, Althaia Xarxa Assistencial de Manresa, 08243 Manresa, Spain; [email protected] *Correspondence: [email protected]; Tel.: +34-671251375 Abstract: The Action Research Arm Test (ARAT) can provide subjective results due to the difficulty assessing abnormal patterns in stroke patients. The aim of this study was to identify joint impairments and compensatory grasping strategies in stroke patients with left (LH) and right (RH) hemiparesis. An experimental study was carried out with 12 patients six months after a stroke (three women and nine men, mean age: 65.2 ± 9.3 years), and 25 healthy subjects (14 women and 11 men, mean age: 40.2 ±18.1 years . The subjects were evaluated during the performance of the ARAT using a data glove. Stroke patients with LH and RH showed significantly lower flexion angles in the MCP joints of the Index and Middle fingers than the Control group. However, RH patients showed larger flexion angles in the proximal interphalangeal (PIP) joints of the Index, Middle, Ring, and Little fingers. In contrast, LH patients showed larger flexion angles in the PIP joints of the Middle and Little fingers. Therefore, the results showed that RH and LH patients used compensatory strategies involving increased flexion at the PIP joints for decreased flexion in the MCP joints. The integration of a data glove during the performance of the ARAT allows the detection of finger joint impairments in stroke patients that are not visible from ARAT scores. Therefore, the results presented are of clinical relevance. Keywords: hand; stroke; rehabilitation; finger joints; data glove 1. Introduction Stroke remains the second-leading cause of death and the third-leading cause of death and disability combined globally. Projections show that the burden of stroke will not decrease in the next decade or beyond [ 1 ]. An important contributing factor is that the number of older persons in Europe is rising, with a projected increase of 35% between 2017 and 2050 [ 2 ]. Stroke is caused by the death of brain cells as a result of blockage of a blood vessel supplying the brain (ischemic stroke) or bleeding into or around the brain (hemorrhagic stroke) [ 3 ]; the disability and the rehabilitation that is needed poststroke depends on the size of the brain injury and the particular brain circuits that are damaged [ 4 ]. The most common sequelae caused by stroke is motor impairment, which impairs function in muscle movement or mobility [ 5 ]. One of the most affected parts are the upper extremities (UEs) of the human body; movement problems in these parts limit the quality of life by limiting the ability to perform activities of daily living (ADLs). The hand is one of the essential tools of the human body, allowing us to perform a wide variety of actions to interact with the environment, such as touching, reaching, holding, grasping, and manipulating different types of objects. People who suffer the loss of mobility in the hand endure a tremendous negative impact on their living standards, causing problems in their family, work, and social environment. Therefore, the rehabilitation process after a stroke is Sensors 2022,22, 3604. https://doi.org/10.3390/s22103604 https://www.mdpi.com/journal/sensors Sensors 2022,22, 3604 2 of 14 fundamental to prevent deterioration of function, reduce motor disability and reintegrate patients into their ADLs [ 6 ]. Stroke rehabilitation is divided into three phases: acute phase (first week), subacute phase (one–six months), and chronic phase (after six months) [ 7 ]. In order to evaluate the patient’s progress during the rehabilitation program, it is highly recommended to use standardized outcome measures (OMs) with good psychometric properties. There is a wide range of upper extremity rehabilitation OMs (e.g., motor function, muscle strength, dexterity, global stroke severity, and others) [ 8 ]. Many physical therapists have assessed the upper limb function in post-stroke patients with the Action Research Arm Test (ARAT). The ARAT is a measurement tool used to assess UE functional limitations. The test described by Lyle [ 9 ] evaluates 19 tests of arm motor function that assess a patient’s ability to handle objects differing in size, weight, and shape. Each test is given an ordinal score of 0, 1, 2, or 3, with higher values indicating better arm motor status [10]. The test has shown good reliability and validity [10–12]. The ARAT, like other OMs, is evaluated by an examiner who determines the score of each test. The scoring process can lead to subjective results due to the difficulty of assessing abnormal patterns in patients after stroke. Therefore, as a result of technological advances, wearable sensors have been incorporated during the performance of various OMs in several clinical investigations. The use of sensors allows having more quantitative and sensitive assessment methods during clinical rehabilitation of the UEs. Most research studies have used inertial measurement units (IMUs) while performing the ARAT. Carpinella et al. proposed a method to discriminate between healthy subjects and multiple sclerosis patients wearing a single inertial sensor on the wrist [ 13 ]. Nam et al. obtained a database of the workspace and range of motion (ROM) of the major joints of the UEs in healthy subjects using a wearable motion capture system based on an (IMU) [ 14 ]. Repnik et al. proposed a system of IMUs for kinematic quantification and electromyography (EMG) sensors for muscle activity analysis in stroke patients [ 15 ]. Held et al. measured arm kinematics in stroke patients during different stages of the rehabilitation process using an Xsens full-body motion capture suit (Xsens Technologies, Enschede, Netherlands) [ 16 ]. In contrast, Dutta et al. evaluated grasp abilities by deploying intelligent algorithms with healthy subjects and post-stroke patients using an instrumented glove composed of six flex sensors, three force sensors, and a motion processing unit [ 17 ]. During the Wolf Motor Function Test execution, Del Din et al. used six accelerometers placed on the arm and the trunk to estimate Fugl–Meyer Assessment Test scores [ 18 ]. Finally, Routhier et al. studied the correlation between finger-to-nose task (FNT) and upper limb motor function in subacute stroke patients, using an IMU [ 19 ]. Although many of these studies evaluated the UEs with sensory information during OMs, none of them focused on the assessment of hand function by studying the range of motion (ROM) of the finger joints. Nevertheless, several studies have been conducted on the functional range of motion (FROM) of the finger joints during the performance of ADLs in healthy subjects [ 20 – 22 ]. Despite this, only Bain et al., who used the Sollerman hand grip function test [ 23 ], and Hayashi et al., who used 19 activities of the Disabilities of the Arm, Shoulder, and Hand (DASH) [ 24 ], used rehabilitation OMs. To the best of our knowledge, no study has determined the FROM and the ROM of the finger joints in stroke patients during the performance of the ARAT using a data glove. This study aimed to determine whether differences in the FROM and the ROM of finger joints between healthy subjects and poststroke patients allow the identification of joint motion impairments and compensatory strategies in stroke patients that are not detected with the ARAT. The data obtained are of clinical importance for physiotherapists, as they allow a more quantitative and objective evaluation method. 2. Materials and Methods 2.1. Subjects Twelve patients (3 women and 9 men, mean age: 65.2 ± 9.3 years; right-handed) were evaluated six months after a stroke at Sant Joan de Deu Hospital. Ten patients suffered an Sensors 2022,22, 3604 3 of 14 ischemic stroke, and two patients a hemorrhagic stroke. Inclusion criteria for this study included the following: patients who had a stroke for the first time with motor deficits in the UEs; patients older than 18 years; patients who, before the stroke, were independent in their ADLs; patients with a global ARAT score ≥ 10. Exclusion criteria: patients with UE deficits and sequelae of any etiology before the stroke. Data from the control group used in this study were taken from a publicly available dataset [ 25 ] obtained in previous research. The dataset includes information from 25 healthy subjects (14 women and 11 men, mean age: 40.2 ± 18.1 years). Inclusion criteria were being right-handed, over 18 years old, and not having suffered any hand disorders or injury. Healthy subjects performed sixteen activities of the ARAT corresponding to the subtests (Grasp, Grip, and Pinch) using an instrumented glove (Cyberglove Systems LLC; San Jose, CA, USA). All subjects signed informed consent to the protocol, which was conformed following the Declaration of Helsinki and was approved by the Ethics and Clinical Research Committee of the Fundacio UnióCatalana d’Hospitals ID 13/71. The stroke patients were divided into two groups to evaluate and detect impairments of the finger joints. Therefore, we formed one group of patients with hemiparesis on the right side and the other with hemiparesis on the left side. The information of the two stroke groups and the control group is shown in Table 1. Table 1. Characteristics of the groups. Variable Groups RH LH C Age (Mean ±SD) 62 ±10.3 69.6 ±5.3 40.2 ±18.1 Hemisphere Affected L R - Subjects (N) 7 5 25 S. Grasp (tests) 31 24 150 S. Grip tests (tests) 19 16 100 S. Pinch tests (tests) 30 24 150 Total (tests) 80 64 400 TSS 6 6 - ARAT score (Mean ±SD) 39.2 ±14.3 45.4 ±13.7 - RH = right hemiparesis; LH = left hemiparesis; C = control group; SD = standard deviation; L = left; R = right; N = Number of participants; tests = complete test (ARAT score ≥ 2); S = subtest; TS = time since stroke (months). 2.2. Experimental Protocol In the present study, post-stroke patients performed sixteen tests (see Table 2) of the ARAT. These tests correspond to the Grasp, Grip, and Pinch subtests. The ARAT is an evaluative measure used to assess the arm motor status after a stroke, consisting of 19 tests categorized into four subtests: Grasp, Grip, Pinch, and Gross movements. Within each subtest, the first test is the most difficult and the second the easiest to facilitate the application of the test [ 9 ]. The Gross movement subtest was excluded because it involves the assessment of large muscle movements and, in this study, we focused on measuring the finger joints. Stroke patients sat upright in a standard chair with a firm back and no armrests. The assessments were performed in the hospital by a trained therapist. Subjects were seated in front of a table; the table was set at a distance of 15 cm and at the abdomen level. The physical therapist ensured that the subject’s back remained in contact with the back of the chair and that the legs were positioned in front of the chair with the feet in contact with the floor throughout the test. The subject was asked to grasp, lift vertically, place, and then release each object (block, cricket ball, or marble) onto the top of the shelf. The objects used in each activity were placed one at a time on the table. The ARAT performance score is rated on a 4-point scale, ranging from 0 (no movement) to 3 (movement performed normally). A full description of all ARAT tasks was presented in [ 10 ]. In this study, only the ARAT activities that the patient was able to complete, which obtained a score of 2 (complete task that takes a little longer) and 3 (complete task), were analyzed and compared with the control group. Sensors 2022,22, 3604 4 of 14 Table 2. Description of the sixteen tests performed. Subtest Test Description Grasp 1Grasp a block (10 cm3), lift vertically, place, and then release onto the top of the shelf. 2Grasp a block (2.5 cm3), lift vertically, place, and then release onto the top of the shelf. 3Grasp a block (5 cm3), lift vertically, place, and then release onto the top of the shelf. 4Grasp a block (7.5 cm3), lift vertically, place, and then release onto the top of the shelf. 5 Grasp a cricket ball (diameter, 7 cm), lift vertically, place, and then release onto the top of the shelf. 6 Grasp a sharpening stone (10.0 × 2.5 × 1 cm), lift vertically, place, and then release onto the top of the shelf. Grip 7 Pour water from one glass to another. 8 Displace alloy tube (diameter, 2.25 cm) from one side of table to the other. 9 Displace alloy tube (diameter, 1 cm) from one side of table to the other. 10 Put a washer over bolt (outer diameter, 3.5 cm; inner diameter,1.5 cm). Pinch 11 Ball bearing (diameter, 6 mm), held between ring finger and thumb. 12 Marble (diameter, 1.6 cm), held between index finger and thumb. 13 Ball bearing (diameter, 6 mm), held between middle finger and thumb. 14 Ball bearing (diameter, 6 mm), held between index finger and thumb. 15 Marble (diameter, 1.6 cm), held between ring finger and thumb. 16 Marble (diameter, 1.6 cm), held between middle finger and thumb. 2.3. Experimental Equipment Subjects performed the sixteen activities of the ARAT wearing the CyberGlove II ® data glove on the affected hand of subjects with hemiparesis and on the right hand (dominant) of healthy subjects (Figure 1). The data glove is composed of 18 flexion sensors: two bend sensors on each finger, four abduction sensors, and sensors measuring thumb crossover, palm arch, wrist flexion, and wrist abduction. The data glove has a resolution <1 degree and weighs only 70 g [ 26 ]. The procedure for converting the readings of the 18 sensors into finger joint angles was based on linear interpolation, according to a previously validated calibration protocol [ 27 , 28 ]. The eleven finger joints angles recorded in this study were: Thumb carpometacarpal (CMC) joint, Thumb, Index, Middle, Ring, and Little metacarpophalangeal (MCP) joints, Thumb interphalangeal (IP) joint, and Index, Middle, Ring, and Little proximal interphalangeal (PIP) joints. Data from the CyberGlove II ® were transmitted to a PC via Bluetooth connection. To read and record the data, a user interface (UI) was developed in Unity ® software (Unity Technologies Inc., San Francisco, CA, USA) version 2021.1.20. A script was created in order to convert the raw data of the CyberGlove II ® into angles according to the equations obtained in the calibration process. The UI allows visualizing the angle of the finger joints in real time, and evaluation of each activity. The angles of the eleven finger joints obtained in each test were recorded in a Comma-Separated Values (CSV) file for statistical analysis. 2.4. Data Analysis The data obtained were filtered with a 2nd-order two-way low pass Butterworth filter with a cut-off frequency of 5 Hz in MATLAB ® software MathWorks, Inc., Natick, MA, USA. The following protocol was applied separately to the control group and the stroke groups. At the start of each test, the subject placed the hand tested pronated, immediately lateral to the testing object. Therefore, the initial instants of each record, in which the hand were static, were trimmed. The minimum and maximum values for each activity were calculated for each finger joint of each subject. The respective values were averaged across all subjects during each activity; these values became known as the extension and flexion angles (E/F). Then, the functional range of motion (FROM) was calculated as the 5th and 95th percentiles of the (E/F) angles of each finger joint in the sixteen activities, thus representing the maximum and minimum angles covering 90% of the activities at each specific finger joint. The FROM was used based on 90% of activities because considering 100% of activities may result in excessive values [ 21 , 23 ]. Alternatively, the range of motion (ROM) was defined as the average of the E/F angles of the finger joints during the sixteen activities of the ARAT. Sensors 2022,22, 3604 5 of 14 Similarly, the total arc of motion (aROM) was defined as the range of flexion and extension angles that compose the ROM. Finally, the range of motion for each finger joint in each subtest (sROM) was calculated. The sROM was defined as the average of the extension and flexion angles corresponding to the activities of the subtest considered. Sensors 2022, 22, x FOR PEER REVIEW 5 of 15 Figure 1. A participant wearing the CyberGlove II®. 2.4. Data Analysis The data obtained were filtered with a 2nd-order two-way low pass Butterworth filter with a cut-off frequency of 5 Hz in MATLAB® software MathWorks, Inc., Natick, MA, USA. The following protocol was applied separately to the control group and the stroke groups. At the start of each test, the subject placed the hand tested pronated, immediately lateral to the testing object. Therefore, the initial instants of each record, in which the hand were static, were trimmed. The minimum and maximum values for each activity were calculated for each finger joint of each subject. The respective values were averaged across all subjects during each activity; these values became known as the extension and flexion angles (E/F). Then, the functional range of motion (FROM) was calculated as the 5th and 95th percentiles of the (E/F) angles of each finger joint in the sixteen activities, thus representing the maximum and minimum angles covering 90% of the activities at each specific finger joint. The FROM was used based on 90% of activities because considering 100% of activities may result in excessive values [21,23]. Alternatively, the range of motion (ROM) was defined as the average of the E/F angles of the finger joints during the sixteen activities of the ARAT. Similarly, the total arc of motion (aROM) was defined as the range of flexion and extension angles that compose the ROM. Finally, the range of motion for each finger joint in each subtest (sROM) was calculated. The sROM was defined as the average of the extension and flexion angles corresponding to the activities of the subtest considered. Statistical analysis was conducted using IBM SPSS Statistics, Version 28.0. Armonk, NY, USA: IBM Corp. The respective extension and flexion angles (ROM) of each finger joint were compared between control and each stroke group using a non-parametric test, the Mann–Whitney U test. In each subtest (Grasp, Grip, and Pinch), the Mann–Whitney U test was used to compare whether there was a statistical difference in the sROM of the finger joints between the control group and each stroke group. Additionally, the flexion angles of the FROM in each finger joint were compared between the right hemiparesis, left hemiparesis, and control groups. For this purpose, a Welch’s ANOVA and a Games– Howell post hoc test was used to detect significant differences. Lastly, the ROM and aROM of each finger joint were compared between the right hemiparesis and the left hemiparesis groups using the Mann–Whitney U test. A p-value of less than 0.05 was considered statistically significant for all statistical analyses. Figure 1. A participant wearing the CyberGlove II®. Statistical analysis was conducted using IBM SPSS Statistics, Version 28.0. Armonk, NY, USA: IBM Corp. The respective extension and flexion angles (ROM) of each finger joint were compared between control and each stroke group using a non-parametric test, the Mann–Whitney U test. In each subtest (Grasp, Grip, and Pinch), the Mann–Whitney U test was used to compare whether there was a statistical difference in the sROM of the finger joints between the control group and each stroke group. Additionally, the flexion angles of the FROM in each finger joint were compared between the right hemiparesis, left hemiparesis, and control groups. For this purpose, a Welch’s ANOVA and a Games–Howell post hoc test was used to detect significant differences. Lastly, the ROM and aROM of each finger joint were compared between the right hemiparesis and the left hemiparesis groups using the Mann–Whitney U test. A p-value of less than 0.05 was considered statistically significant for all statistical analyses. 3. Results 3.1. Functional Range of Motion of the Finger Joints The functional range of motion (FROM) of the finger joints required to perform 90% of the activities for each group is shown in Figure 2. In this study we decided to analyze the mean flexion angles of the 14 tasks that integrate the FROM. Mean and standard deviation values of the mean flexion angles (FROM) of each finger joint in the control, right hemiparesis (RH), and left hemiparesis (LH) groups are shown in Table 3. A Welch’s ANOVA revealed that there was a statistically significant difference in the flexion angle of the Thumb IP, Index MCP, Index PIP, Middle MCP, Middle PIP, Ring PIP, and Little PIP finger joints between the control, right hemiparesis (RH), and left hemiparesis (LH) groups. The results of the post hoc test (see Table 3) showed that the mean flexion angles of the Index MCP and Middle MCP in the control group were significantly larger than those in the RH group. In contrast, the mean flexion angles of the Thumb IP, Middle PIP, Ring PIP, Little MCP, and Little PIP in the RH group were significantly larger than those in the control group. The mean flexion angles of the Thumb IP, Middle PIP, and Little PIP in the LH group were significantly higher than those in the control group. However, the mean flexion angles in the Middle MCP joint in the control group were significantly larger than those in Sensors 2022,22, 3604 6 of 14 the RH group. Moreover, the mean flexion angles of the Thumb IP and Middle MCP in the LH group were significantly higher than those in the RH group. Lastly, the mean flexion angles of the PIP joints (Index, Middle, and Ring) in the RH group were significantly larger than those in the LH group. Sensors 2022, 22, x FOR PEER REVIEW 6 of 15 3. Results 3.1. Functional Range of Motion of the Finger Joints The functional range of motion (FROM) of the finger joints required to perform 90% of the activities for each group is shown in Figure 2. In this study we decided to analyze the mean flexion angles of the 14 tasks that integrate the FROM. Mean and standard deviation values of the mean flexion angles (FROM) of each finger joint in the control, right hemiparesis (RH), and left hemiparesis (LH) groups are shown in Table 3. A Welch’s ANOVA revealed that there was a statistically significant difference in the flexion angle of the Thumb IP, Index MCP, Index PIP, Middle MCP, Middle PIP, Ring PIP, and Little PIP finger joints between the control, right hemiparesis (RH), and left hemiparesis (LH) groups. The results of the post hoc test (see Table 3) showed that the mean flexion angles of the Index MCP and Middle MCP in the control group were significantly larger than those in the RH group. In contrast, the mean flexion angles of the Thumb IP, Middle PIP, Ring PIP, Little MCP, and Little PIP in the RH group were significantly larger than those in the control group. The mean flexion angles of the Thumb IP, Middle PIP, and Little PIP in the LH group were significantly higher than those in the control group. However, the mean flexion angles in the Middle MCP joint in the control group were significantly larger than those in the RH group. Moreover, the mean flexion angles of the Thumb IP and Middle MCP in the LH group were significantly higher than those in the RH group. Lastly, the mean flexion angles of the PIP joints (Index, Middle, and Ring) in the RH group were significantly larger than those in the LH group. Figure 2. Functional range of motion in each finger joint; CMC = carpometacarpal; MCP = metacarpophalangeal; IP = interphalangeal; PIP = proximal interphalangeal; negative values represent hyperextension; maximum = flexion; minimum = extension. Table 3. Flexion angles of the functional range of motion (FROM) during 14 tests. Finger Joints C RH L M(C-RH) M(C-LH) M(RH-LH) F SD F SD F SD M P M p M p Thumb CMC 28.2 5.0 26.5 4.8 26.6 0.7 1.65 0.629 1.55 0.474 −0.10 0.996 Figure 2. Functional range of motion in each finger joint; CMC = carpometacarpal; MCP = metacarpophalangeal; IP = interphalangeal; PIP = proximal interphalangeal; negative values represent hyperextension; maximum = flexion; minimum = extension. Table 3. Flexion angles of the functional range of motion (FROM) during 14 tests. Finger Joints C RH L M(C-RH) M(C-LH) M(RH-LH) F SD F SD F SD M pMpMp Thumb CMC 28.2 5.0 26.5 4.8 26.6 0.7 1.65 0.629 1.55 0.474 −0.10 0.996 Thumb MCP 26.4 3.3 29.1 4.2 29.9 5.0 −2.70 0.143 −3.48 0.084 −0.78 0.887 Thumb IP 12.6 4.1 26.8 5.1 21.7 4.1 −14.21 0.000 *** −9.16 0.000 *** 5.04 0.016 ** Index MCP 45.0 8.3 35.8 3.4 40.4 6.2 9.18 0.002 ** 4.53 0.224 −4.64 0.047 * Index PIP 37.8 8.7 43.7 11.3 30.6 11.4 −5.84 0.269 7.24 0.143 13.09 0.010 * Middle MCP 46.4 7.0 34.9 4.6 34.8 7.0 11.46 0.000 *** 11.54 0.000 *** 0.083 0.999 Middle PIP 41.6 6.8 59.6 9.9 51.3 8.1 −17.99 0.000 *** −9.77 0.003 ** 8.22 0.048 * Ring MCP 42.8 9.3 49.6 7.3 48.8 10.7 −6.78 0.085 −5.99 0.246 0.79 0.970 Ring PIP 38.2 6.5 54.2 7.3 39.2 6.9 −16.00 0.000 *** −1.02 0.909 14.97 0.000 *** Little MCP 30.1 6.6 38.9 9.9 33.4 5.1 −8.80 0.023 * −3.34 0.284 5.45 0.166 Little PIP 21.3 4.2 47.2 11.5 48.1 8.8 −25.87 0.000 *** −26.73 0.000 *** −0.86 0.971 Games–Howell post-hoc comparison; C = control group; RH = right hemiparesis; LH = left hemiparesis; F = flexion ; SD = standard deviation; CMC = carpometacarpal; MCP = metacarpophalangeal; IP = interphalangeal; PIP = proximal interphalangeal; negative values represent hyperextension; * p< 0.05; ** p< 0.01; *** p< 0.001 ; M = mean differences between groups; p= significance level. 3.2. Range of Motion of the Finger Joints in the Stroke Group with Right Hemiparesis Mean and standard deviation values of the range of motion (ROM) and the total arc of motion (aROM) of each finger joint in the control and the stroke group with right hemiparesis (RH) are shown in Table 4. As reported in Table 5, the extension angles of the Thumb CMC, Index MCP, Middle MCP joints in the control group were significantly lower Sensors 2022,22, 3604 7 of 14 than those in the RH group. In contrast, the RH group showed significantly lower extension angles in the Thumb IP, Middle PIP, Ring MCP, Ring PIP, Little MCP, and Little PIP joints. The flexion angles of the Index MCP and Middle MCP joints in the control group were significantly higher than those in the RH group, while flexion angles of the Thumb MCP, Thumb IP, Index PIP, Middle PIP, Ring MCP, Ring PIP, Little MCP, and Little PIP joints in the RH group were significantly higher (see Table 5). The aROM in the control group was significantly larger than that in the RH group in the Middle MCP joint. By comparison, the aROM of the Thumb MCP, Index PIP, Middle PIP, Ring PIP, and Little PIP joints in the RH group was significantly larger (see Table 5). Table 4. Range of motion (ROM) during the sixteen activities (control and right hemiparesis). Extension (Degree) Flexion (Degree) aROM (Degree) C RH C RH C RH Finger Joints Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD Thumb CMC 9.7 7.5 5.6 7.5 28.6 7.4 26.8 10.0 18.9 6.4 21.2 9.6 Thumb MCP 12.6 9.3 11.3 10.5 26.8 8.9 29.7 11.4 14.3 7.3 18.4 10.6 Thumb IP −7.5 16.2 6.4 16.4 13.2 14.9 28.3 16.9 20.7 13.7 21.9 15.6 Index MCP 22.2 13.1 11.2 15.3 46.2 13.5 36.5 12.4 24.0 12.1 25.4 13.3 Index PIP 16.4 9.2 15.8 10.3 38.9 14.0 44.2 16.5 22.4 11.1 28.4 16.8 Middle MCP 17.8 11.9 14.0 12.8 47.5 11.5 36.0 12.6 29.7 10.9 22.0 10.2 Middle PIP 16.3 8.5 27.3 14.5 42.6 11.4 60.0 15.4 26.3 9.3 32.7 15.5 Ring MCP 15.6 11.8 20.6 14.7 44.1 13.6 49.8 13.0 28.5 11.4 29.3 15.7 Ring PIP 12.3 8.1 23.9 13.6 39.2 11.8 54.3 14.1 26.9 9.8 30.5 12.2 Little MCP 9.1 8.8 13.2 8.0 31.5 12.1 39.3 15.1 22.4 8.9 26.2 14.9 Little PIP 11.3 9.5 15.4 11.0 22.1 13.4 47.5 21.6 10.8 8.3 32.1 19.6 C = control group; RH = right hemiparesis group; CMC = carpometacarpal; MCP = metacarpophalangeal; IP = interphalangeal ; PIP = proximal interphalangeal; SD = standard deviation; deg = degrees; aROM = arc of motion; negative values represent hyperextension. Table 5. Results of Mann–Whitney test of the ROM with respect to the control and right hemiparesis groups. Extension Flexion aROM Finger Joint Group N Mean Rank U Z pMean Rank U Z pMean Rank U Z p Thumb CMC C 400 252.9 11,023.0 −4.39 0.000 *** 245.6 13,959.5 −1.80 0.072 236.2 14,262.0 −1.53 0.125 RH 80 178.3 215.0 262.2 Thumb MCP C 400 243.1 14,949.0 −0.93 0.353 234.2 13,489.0 −2.22 0.027 * 231.8 12,518.0 −3.07 0.002 ** RH 80 227.4 271.9 284.0 Thumb IP C 400 222.4 8764.5 −6.39 0.000 *** 219.1 7435.0 −7.56 0.000 *** 239.5 15,610.0 −0.34 0.731 RH 80 330.9 347.6 245.4 Index MCP C 400 257.7 9136.0 −6.06 0.000 *** 256.6 9555.5 −5.69 0.000 *** 238.4 15,146.0 −0.75 0.451 RH 80 154.7 159.9 251.2 Index PIP C 400 242.9 15,058.0 −0.83 0.406 232.7 12,877.5 −2.76 0.006 ** 233.1 13,055.0 −2.60 0.009 ** RH 80 228.7 279.5 277.3 Middle MCP C 400 248.6 12,758.0 −2.86 0.004 ** 259.7 8302.5 −6.80 0.000 *** 258.2 8940.0 −6.23 0.000 *** RH 80 200.0 144.3 152.3 Middle PIP C 400 223.0 9002.0 −6.18 0.000 *** 215.7 6092.5 −8.75 0.000 *** 230.6 12,029.0 −3.51 0.000 *** RH 80 328.0 364.3 290.1 Ring MCP C 400 231.6 12,459.0 −3.13 0.002 ** 229.8 11,706.0 −3.79 0.000 *** 240.8 15,874.0 −0.11 0.911 RH 80 284.8 294.2 238.9 Ring PIP C 400 220.7 8085.0 −6.99 0.000 *** 217.0 6593.5 −8.31 0.000 *** 233.9 13,363.0 −2.33 0.020 ** RH 80 339.4 358.1 273.5 Little MCP C 400 230.4 11,941.0 −3.58 0.000 *** 228.0 11,012.0 −4.40 0.000 *** 236.8 14,521.0 −1.31 0.192 RH 80 291.2 302.9 259.0 Little PIP C 400 231.4 12,372.0 −3.20 0.001 ** 213.5 5192.0 −9.54 0.000 *** 211.6 4450.0 −10.20 0.000 *** RH 80 285.9 375.6 384.9 C = control group; RH = right hemiparesis group; * p< 0.05; ** p< 0.01; *** p< 0.001; control vs. stroke Mann–Whitney U test.; N = number of tests per group. Sensors 2022,22, 3604 8 of 14 3.3. Range of Motion of the Finger Joints in the Stroke Group with Left Hemiparesis The range of motion (ROM) and the total arc of motion (aROM) of each finger joint in the control and the stroke group with left hemiparesis (LH) are shown in Table 6. As shown in Table 7, the extension angles of the Thumb CMC, Index MCP and PIP, Middle MCP joints in the control group were significantly lower than those in the LH group. In contrast, the LH group showed significantly lower extension angles in the Thumb IP, Middle PIP, Little MCP, and Little PIP joints. The flexion angles of the Index (MCP, PIP) and Middle MCP joints in the control group were significantly larger than those in the LH group, while flexion angles in the LH group were significantly larger in the Thumb MCP, Thumb IP, Middle PIP, Ring MCP, Little MCP, and Little PIP joints (see Table 7). The aROM of the Thumb IP and Little MCP joints in the control group was significantly larger than that in the LH group. In addition, aROM in the LH group was significantly larger in the Thumb MCP and Little PIP joints (see Table 7). Table 6. Range of motion (ROM) during the sixteen activities (control and left hemiparesis). Finger Joints Extension (Deg) Flexion (Deg) aROM (Deg) C LH C LH C LH Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD Thumb CMC 9.7 7.5 8.1 1.8 28.6 7.4 26.7 1.5 18.9 6.4 18.6 1.6 Thumb MCP 12.6 9.3 11.1 6.5 26.8 8.9 30.4 10.0 14.3 7.3 19.2 10.9 Thumb IP −7.5 16.2 7.2 8.7 13.2 14.9 22.7 8.5 20.7 13.7 15.5 9.4 Index MCP 22.2 13.1 14.0 18.9 46.2 13.5 41.8 13.0 24.0 12.1 27.9 21.9 Index PIP 16.4 9.2 8.4 11.9 38.9 14.0 32.5 19.3 22.4 11.1 24.1 15.2 Middle MCP 17.8 11.9 7.1 13.1 47.5 11.5 36.4 15.5 29.7 10.9 29.3 18.6 Middle PIP 16.3 8.5 25.8 11.4 42.6 11.4 52.2 13.1 26.3 9.3 26.3 11.8 Ring MCP 15.6 11.8 17.4 13.4 44.1 13.6 50.9 17.3 28.5 11.4 33.5 16.7 Ring PIP 12.3 8.1 15.8 10.0 39.2 11.8 40.1 13.2 26.9 9.8 24.4 11.8 Little MCP 9.1 8.8 21.1 4.6 31.5 12.1 34.5 7.3 22.4 8.9 13.4 7.3 Little PIP 11.3 9.5 21.7 10.4 22.1 13.4 49.6 16.9 10.8 8.3 27.8 15.9 C = control group; LH = left hemiparesis group; CMC = carpometacarpal; MCP = metacarpophalangeal; IP = interphalangeal ; PIP = proximal interphalangeal; SD = standard deviation; deg = degrees; aROM = arc of motion; negative values represent hyperextension. Table 7. Results of Mann–Whitney test of the ROM with respect to the control and left hemiparesis groups. Extension Flexion aROM Finger Joint Group N Mean Rank U Z pMean Rank U Z pMean Rank U Z p Thumb CMC C 400 239.04 10,184 −2.63 0.009 ** 241.31 9276.5 −3.54 0.000 *** 231.11 12,245 −0.56 0.577 LH 64 191.63 177.45 241.17 Thumb MCP C 400 236.86 11,055 −1.75 0.080 225.95 10,181 −2.63 0.009 ** 223.10 9038 −3.78 0.000 *** LH 64 205.23 273.42 291.28 Thumb IP C 400 214.15 5459 −7.37 0.000 *** 216.74 6494.5 −6.33 0.000 *** 239.12 10,152 −2.66 0.008 ** LH 64 347.20 331.02 191.13 Index MCP C 400 239.85 9862 −2.95 0.003 ** 237.69 10,724 −2.08 0.037 * 232.16 12,665 −0.14 0.892 LH 64 186.59 200.06 234.61 Index PIP C 400 246.80 7081 −5.74 0.000 *** 240.10 9761 −3.05 0.002 ** 232.36 12,744 −0.06 0.955 LH 64 143.14 185.02 233.38 Middle MCP C 400 248.15 6540 −6.29 0.000 *** 244.94 7825 −5.00 0.000 *** 236.83 11,070 −1.74 0.082 LH 64 134.69 154.77 205.47 Middle PIP C 400 216.99 6595 −6.23 0.000 *** 219.62 7649 −5.17 0.000 *** 234.35 12,061 −0.74 0.458 LH 64 329.45 312.98 220.95 Ring MCP C 400 229.43 11,573 −1.23 0.218 224.78 9712.5 −3.10 0.002 ** 227.78 10,910 −1.90 0.058 LH 64 251.67 280.74 262.03 Ring PIP C 400 227.95 10,981 −1.83 0.068 230.32 11,926 −0.88 0.380 237.09 10,963 −1.84 0.065 LH 64 260.92 246.16 203.80 Sensors 2022,22, 3604 9 of 14 Table 7. Cont. Extension Flexion aROM Finger Joint Group N Mean Rank U Z pMean Rank U Z pMean Rank U Z p Little MCP C 400 207.59 2836 −10.00 0.000 *** 224.78 9712 −3.10 0.002 ** 251.12 5353 −7.48 0.000 *** LH 64 388.19 280.75 116.14 Little PIP C 400 216.00 6198 −6.63 0.000 *** 207.51 2805 −10.04 0.000 *** 211.14 4257 −8.58 0.000 *** LH 64 335.66 388.67 365.98 C = control group; LH = left hemiparesis group; * p< 0.05; ** p< 0.01; *** p< 0.001; control vs. LH Mann–Whitney U test.; N = number of tests per group. 3.4. Comparison of the Range of Motion between the Stroke Groups The results of the comparison between the stroke groups are shown in Table 8. The results showed than the extension angles of the Thumb CMC and Little (MCP, PIP) joints in the left hemiparesis (LH) group were significantly lower than those in the right hemiparesis (RH) group. In contrast, the extension angles of the Index PIP and Middle MCP joints in the RH group were significantly lower. The flexion angles of the PIP joints of the Index, Middle and Ring fingers in the RH group were significantly larger than those in the LH group, while, in the LH group, the flexion angle of the Index MCP joint was significantly larger. Lastly, the arc of motion of the Thumb IP, Middle PIP, Ring PIP and Little MCP in the LH group was significantly larger. Table 8. Results of Mann–Whitney test of the ROM with respect to the stroke groups (left hemiparesis vs. right hemiparesis). Extension Flexion aROM Finger Joint Group N Mean Rank U Z pMean Rank U Z pMean Rank U Z p Thumb CMC LH 64 82.45 1923.5 −2.56 0.010 ** 72.65 2550.5 −0.04 0.970 69.84 2390 −0.68 0.494 RH 80 64.54 72.38 74.63 Thumb MCP LH 64 70.77 2449.5 −0.44 0.657 73.89 2471 −0.36 0.720 75.74 2352.5 −0.83 0.404 RH 80 73.88 71.39 69.91 Thumb IP LH 64 74.30 2445 −0.46 0.644 66.08 2149 −1.65 0.098 61.88 1880 −2.73 0.006 ** RH 80 71.06 77.64 81.00 Index MCP LH 64 76.67 2293 −1.08 0.282 82.09 1946 −2.47 0.013 ** 71.86 2519 −0.17 0.869 RH 80 69.16 64.83 73.01 Index PIP LH 64 55.27 1457 −4.44 0.000 *** 57.24 1583.5 −3.93 0.000 *** 66.38 2168 −1.58 0.115 RH 80 86.29 84.71 77.40 Middle MCP LH 64 60.95 1820.5 −2.97 0.003 ** 73.53 2494 −0.27 0.791 78.67 2165 −1.59 0.112 RH 80 81.74 71.68 67.56 Middle PIP LH 64 70.84 2454 −0.43 0.670 59.94 1756 −3.23 0.001 ** 61.84 1878 −2.74 0.006 ** RH 80 73.83 82.55 81.03 Ring MCP LH 64 66.91 2202.5 −1.44 0.151 73.13 2519.5 −0.16 0.871 78.56 2172 −1.56 0.119 RH 80 76.97 71.99 67.65 Ring PIP LH 64 57.68 1611.5 −3.81 0.000 51.55 1219.5 −5.39 0.000 *** 61.54 1858.5 −2.82 0.005 ** RH 80 84.36 89.26 81.27 Little MCP LH 64 96.03 1054 −6.06 0.000 *** 66.45 2173 −1.56 0.120 50.23 1135 −5.73 0.000 *** RH 80 53.68 77.34 90.31 Little PIP LH 64 85.30 1741 −3.29 0.001 ** 76.23 2321 −0.96 0.337 68.06 2276 −1.14 0.253 RH 80 62.26 69.51 76.05 RH = right hemiparesis group; LH = left hemiparesis group; C = control group; S = stroke group; * p< 0.05; ** p< 0.01; *** p< 0.001; control vs. stroke Mann–Whitney U test.; N = number of tests per group. 4. Discussion To the best of our knowledge, there are no previous studies that measured and evaluated the finger joint motions during a standardized outcome measure such as the ARAT test. In this study, we determined the functional range of motion (FROM) and the range of motion (ROM) of the finger joints of the right hand, with the exception of distal interphalangeal (DIP) joints, using a data glove (CyberGlove II ® ) while performing the Grasp,