Neurological problems affecting hand dexterity

Bibliometric Analysis of Research on the Use of the Nine Hole Peg Test

Manual dexterity is essential for performing daily life tasks, becoming a primary means of interaction with the physical, social, and cultural environment. In this respect, the Nine Hole Peg Test (NHPT) is considered a gold standard for assessing manual dexterity. Bibliometrics is a discipline that focuses on analyzing publications to describe, evaluate, and predict the status and development trends in certain fields of scientific research. We performed a bibliometric analysis to track research results and identify global trends regarding the use of the NHPT. The bibliographic data were retrieved from the Web of Science database and then analyzed using the Bibliometrix R package, resulting in the retrieval of a total of 615 publications from 1988 to 2021. Among the 263 journals investigated, the most prolific were the Multiple Sclerosis Journal, Clinical Rehabilitation, and Multiple Sclerosis and Related Disorders. North America and Europe were the areas with the highest production of publications, with the United States (n = 104) ranking first in terms of the number of publications, followed by the United Kingdom (n = 62) and Italy (n = 62). The analysis of keywords revealed that there were two main lines of research, with one related to the study of recovery and disability of the upper limbs caused by certain diseases and another related to the study of reliability and validity. Structured information can be useful to understand the research trajectory and the uses of this tool.

Validation of a graphic test to quantitatively assess the dominant hand dexterity

Dexterity dysfunction is a key feature of disability in many neurological and non-neurological diseases. The Nine-Hole Peg Test (NHPT) is the most used test to assess hand dexterity in clinical practice but presents limitations. A new graphic test to enhance objective evaluation of the of the dominant hand dexterity is proposed. The task consists in drawing a continuous line in paths composed by a part with multiple orthogonal changes of direction ('meander'), and a second part derived from the Archimedean spiral ('spiral'). The test was validated in 200 healthy controls and 93 neurological patients. 48 patients performed also the NHPT. Several parameters were analyzed, among which total time, total length, number of touches and number of crossings. Healthy subjects display statistically significant differences with respect to pathological subjects in the case of total time, number of touches, and number of crossings (p<0.001), but not in the case of total length (p = 0.27) needed to complete the second sheet. Moreover, healthy controls display a learning effect, the time needed to complete the second sheet was significantly lower than for the first sheet (p<0.001), and an inverse correlation with age was observed (r = 0.56, p<0.001). The comparison between the NHPT and the new test showed a strong positive correlation (r = 0.71, p<0.001) whereas touches and crossing a weak positive one (r = 0.35, p = 0.01). The new test distinguishes between a slow but precise performance and a fast but imprecise performance, thus providing additional information with respect to NHPT.

Assessing manual dexterity: Comparing the WorkAbility Rate of Manipulation Test with the Minnesota Manual Dexterity Test

STUDY DESIGN

Cross-sectional study.

INTRODUCTION

The WorkAbility Rate of Manipulation Test (WRMT), an adaptation of the Minnesota Manual Dexterity Test (MMDT), contains a revised board and protocols to improve its utility for therapy or fitness assessment.

PURPOSE OF THE STUDY

To describe the development and preliminary psychometric properties of WRMT.

METHODS

Sixty-six healthy participants completed MMDT and WRMT in a random order followed by a user experience survey. We compared tests using repeated-measures analysis of variance, test-retest reliability, and examined agreement between tests.

RESULTS

Despite the similarities of these 2 instruments, the different administration protocols resulted in statistically different score distributions (P < .001). Results supported good test-retest reliability of WRMT (placing test ICC = 0.88-0.90 and turning test ICC = 0.68-0.82). The WRMT correlated moderately with MMDT (r = 0.81 in placing test and r = 0.44-0.57 in turning test). Bland-Altman plot showed that the differences in completion time were 3.8 seconds between placing tests and 19.6 (both hands), 0.3 (right hand), and 3.9 (left hand) seconds between turning tests. Overall, participants felt that the instruction of WRMT was easier to follow (44%) and preferred its setup, color, and depth of the test board (49%). Time required to complete 1 panel of 20 disks correlated highly with the time needed to finish a complete trial of 60 disks in both MMDT (r = 0.91-0.97) and WRMT (r = 0.88-0.95).

CONCLUSIONS

Caution is warranted in comparing scores from these 2 test variants.

LEVEL OF EVIDENCE

3b.

Referent control of anticipatory grip force during reaching in stroke: an experimental and modeling study

To evaluate normal and impaired control of anticipatory grip force (GF) modulation, we compared GF production during horizontal arm movements in healthy and post-stroke subjects, and, based on a physiologically feasible dynamic model, determined referent control variables underlying the GF-arm motion coordination in each group. 63% of 13 healthy and 48% of 13 stroke subjects produced low sustained initial force (< 10 N) and increased GF prior to arm movement. Movement-related GF increases were higher during fast compared to self-paced arm extension movements only in the healthy group. Differences in the patterns of anticipatory GF increases before the arm movement onset between groups occurred during fast extension arm movement only. In the stroke group, longer delays between the onset of GF change and elbow motion were related to clinical upper limb deficits. Simulations showed that GFs could emerge from the difference between the actual and the referent hand aperture (R_a) specified by the CNS. Similarly, arm movement could result from changes in the referent elbow position (R_e) and could be affected by the co-activation (C) command. A subgroup of stroke subjects, who increased GF before arm movement, could specify different patterns of the referent variables while reproducing the healthy typical pattern of GF-arm coordination. Stroke subjects, who increased GF after arm movement onset, also used different referent strategies than controls. Thus, altered anticipatory GF behavior in stroke subjects may be explained by deficits in referent control.

Automatic Outcome in Manual Dexterity Assessment Using Colour Segmentation and Nearest Neighbour Classifier

Objective assessment of motor function is an important component to evaluating the effectiveness of a rehabilitation process. Such assessments are carried out by clinicians using traditional tests and scales. The Box and Blocks Test (BBT) is one such scale, focusing on manual dexterity evaluation. The score is the maximum number of cubes that a person is able to displace during a time window. In a previous paper, an automated version of the Box and Blocks Test using a Microsoft Kinect sensor was presented, and referred to as the Automated Box and Blocks Test (ABBT). In this paper, the feasibility of ABBT as an automated tool for manual dexterity assessment is discussed. An algorithm, based on image segmentation in CIELab colour space and the Nearest Neighbour (NN) rule, was developed to improve the reliability of automatic cube counting. A pilot study was conducted to assess the hand motor function in people with Parkinson’s disease (PD). Three functional assessments were carried out. The success rate in automatic cube counting was studied by comparing the manual (BBT) and the automatic (ABBT) methods. The additional information provided by the ABBT was analysed to discuss its clinical significance. The results show a high correlation between manual (BBT) and automatic (ABBT) scoring. The lowest average success rate in cube counting for ABBT was 92%. Additionally, the ABBT acquires extra information from the cubes’ displacement, such as the average velocity and the time instants in which the cube was detected. The analysis of this information can be related to indicators of health status (coordination and dexterity). The results showed that the ABBT is a useful tool for automating the assessment of unilateral gross manual dexterity, and provides additional information about the user’s performance.

Functional classification of grasp strategies used by hemiplegic patients

This study aimed to identify and qualify grasp-types used by patients with stroke and determine the clinical parameters that could explain the use of each grasp. Thirty-eight patients with chronic stroke-related hemiparesis and a range of motor and functional capacities (17 females and 21 males, aged 25–78), and 10 healthy subjects were included. Four objects were used (tissue packet, teaspoon, bottle and tennis ball). Participants were instructed to “grasp the object as if you are going to use it”. Three trials were video-recorded for each object. A total of 456 grasps were analysed and rated using a custom-designed Functional Grasp Scale. Eight grasp-types were identified from the analysis: healthy subjects used Multi-pulpar, Pluri-digital, Lateral-pinch and Palmar grasps (Standard Grasps). Patients used the same grasps with in addition Digito-palmar, Raking, Ulnar and Interdigital grasps (Alternative Grasps). Only patients with a moderate or relatively good functional ability used Standard grasps. The correlation and regression analyses showed this was conditioned by sufficient finger and elbow extensor strength (Pluri-digital grasp); thumb extensor and wrist flexor strength (Lateral pinch) or in forearm supinator strength (Palmar grasp). By contrast, the patients who had severe impairment used Alternative grasps that did not involve the thumb. These strategies likely compensate specific impairments. Regression and correlation analyses suggested that weakness had a greater influence over grasp strategy than spasticity. This would imply that treatment should focus on improving hand strength and control although reducing spasticity may be useful in some cases.

Neurocognitive robot-assisted therapy of hand function

Neurocognitive therapy, according to the Perfetti method, proposes exercises that challenge motor, sensory as well as cognitive functions of neurologically impaired patients. At the level of the hand, neurocognitive exercises typically involve haptic exploration and interaction with objects of various shapes and mechanical properties. Haptic devices are thus an ideal support to provide neurocognitive exercises under well-controlled and reproducible conditions, and to objectively assess patient performance. Here we present three neurocognitive robot-assisted exercises which were implemented on the ReHapticKnob, a high-fidelity two-degrees-of-freedom hand rehabilitation robot. The exercises were evaluated for feasibility and acceptance in a pilot study on five patients suffering from different neurological disorders. Results showed that all patients were able to take part in the neurocognitive robot-assisted therapy, and that the proposed therapy was well accepted by patients, as assessed through subjective questionnaires. Force/torque and position measurements provided insights on the motor strategy employed by the patients during the exploration of virtual object properties, and served as objective assessment of task performance. The fusion of the neurocognitive therapy concept with robot-assisted rehabilitation enriches therapeutic approaches through the focus on haptics, and could provide novel insights on sensorimotor impairment and recovery.

Measures of fine motor skills in people with tremor disorders: appraisal and interpretation

People with Parkinson's disease, essential tremor, or other movement disorders involving tremor have changes in fine motor skills that are among the hallmarks of these diseases. Numerous measurement tools have been created and other methods devised to measure such changes in fine motor skills. Measurement tools may focus on specific features - e.g., motor skills or dexterity, slowness in movement execution associated with parkinsonian bradykinesia, or magnitude of tremor. Less obviously, some tools may be better suited than others for specific goals such as detecting subtle dysfunction early in disease, revealing aspects of brain function affected by disease, or tracking changes expected from treatment or disease progression. The purpose of this review is to describe and appraise selected measurement tools of fine motor skills appropriate for people with tremor disorders. In this context, we consider the tools' content - i.e., what movement features they focus on. In addition, we consider how measurement tools of fine motor skills relate to measures of a person's disease state or a person's function. These considerations affect how one should select and interpret the results of these tools in laboratory and clinical contexts.

Assessing dexterity function: a comparison of two alternatives for the NIH Toolbox

STUDY DESIGN

Clinical measurement.

INTRODUCTION

Manual dexterity is an important aspect of motor function across the age span.

PURPOSE OF THE STUDY

To identify a single measure of manual dexterity for inclusion in the National Institutes of Health (NIH) Toolbox Assessment of Neurological and Behavioral Function.

METHODS

A total of 340 subjects participated in our study. Two alternatives, Rolyan® 9-Hole Peg Test (9-HPT) and Grooved Pegboard test, were compared by assessing their score range across age groups (3-85 yr) and their test-retest reliability, concurrent, and known groups validity.

RESULTS

The 9-HPT was a simple, efficient, and low-cost measure of manual dexterity appropriate for administration across the age range. Test-retest reliability coefficients were 0.95 and 0.92 for right and left hands, respectively. The 9-HPT correlated with Bruininks-Oseretsky Test (BOT) of Motor Proficiency, dexterity subscale, at -0.87 to -0.89 and with Purdue Pegboard at -0.74 to -0.75. The Grooved Pegboard had good test-retest reliability (0.91 and 0.85 for right and left hands, respectively). The Grooved Pegboard correlated with BOT at -0.50 to -0.63 and with Purdue Pegboard at -0.73 to -0.78. However, the Grooved Pegboard required longer administration time and was challenging for the youngest children and oldest adults.

CONCLUSIONS

Based on its feasibility and measurement properties, the 9-HPT was recommended for inclusion in the motor battery of the NIH Toolbox.

LEVEL OF EVIDENCE

NA.

Coordination of grasping and walking in Parkinson's disease

Studies on grasp control underlying manual dexterity in people with Parkinson disease (PD) suggest that anticipatory grasp control is mainly unaffected during discrete tasks using simple two-digit grasp. Nevertheless, impaired hand function during daily activities is one of the most disabling symptoms of PD. As many daily grasping activities occur during functional movements involving the whole body, impairments in anticipatory grasp control might emerge during a continuous dynamic task such as object transport during walking. In this case, grasp control must be coordinated along with multiple body segments. The present study investigated the effect of PD on anticipatory grasp control and intersegmental coordination during walking with a hand-held object. Nine individuals with idiopathic PD (tested OFF and ON medication) and nine healthy age-matched controls carried a grip instrument between their right thumb and index finger during self-paced and fast walking. Although the amplitude of grip forces was higher in standing and walking for subjects with PD, both subjects with PD and control subjects coupled grip and inertial force changes in an anticipatory fashion while walking. However, gait-induced motions of the object relative to that of the trunk (i.e., dampening) was reduced in subjects with PD. Medication increased the dampening in all subjects with PD. We suggest that these differences are associated with impairments in intersegmental coordination.

Assessment of motor function of the hand in aged rhesus monkeys

In the elderly, intact motor functions of the upper extremity are critical for the completion of activities of daily living. Many studies have provided insight into age-related changes in motor function. However, the precise nature and extent of motor impairments of the upper extremity remains unclear. In the current study we have modified two tasks to assess hand/digit function in both young and aged rhesus monkeys. We tested monkeys from 9 to 26 years of age on these tasks to determine the level of fine motor performance across the adult age range. Compared to young monkeys (9-12 years of age), aged monkeys (15-26 years of age) were mildly impaired on fine motor control of the digits. These findings are consistent with previous studies that have found age-related impairment in fine motor function. However, the magnitude and extent of impairment in the current study does differ from previous findings and is likely due to methodological differences in the degree of task complexity.

Coding and use of tactile signals from the fingertips in object manipulation tasks

During object manipulation tasks, the brain selects and implements action-phase controllers that use sensory predictions and afferent signals to tailor motor output to the physical properties of the objects involved. Analysis of signals in tactile afferent neurons and central processes in humans reveals how contact events are encoded and used to monitor and update task performance.

Basal ganglia mechanisms underlying precision grip force control

The classic grasping network has been well studied but thus far the focus has been on cortical regions in the control of grasping. Sub-cortically, specific nuclei of the basal ganglia have been shown to be important in different aspects of precision grip force control but these findings have not been well integrated. In this review, we outline the evidence to support the hypothesis that key basal ganglia nuclei are involved in parameterizing specific properties of precision grip force. We review literature from different areas of human and animal work that converges to build a case for basal ganglia involvement in the control of precision gripping. Following on from literature showing anatomical connectivity between the basal ganglia nuclei and key nodes in the cortical grasping network, we suggest a conceptual framework for how the basal ganglia could function within the grasping network, particularly as it relates to the control of precision grip force.

Prolonged intracortical delay of long-latency reflexes: electrophysiological evidence for a cortical dysfunction in multiple sclerosis

Convincing evidence suggests that long-latency reflexes (LLRs) are capable of testing the transcortical sensorimotor reflex arch. By subtracting the sum of the latencies of N20 (afferent branch) and transcranially elicited motor evoked potentials (MEP; efferent branch) from the LLR II latency, the cortical relay time (CRT) can also be obtained, which is alleged to represent the time required for the cortical sensorimotor integration. The aim of the present study was to investigate if a cortical dysfunction occurs in multiple sclerosis (MS). Median nerve somatosensory evoked potentials (SEPs), MEPs and LLRs were recorded from the upper limbs of 23, not severely disabled MS patients in acute phases of the disease. Eighteen age and sex matched healthy volunteers served as controls. N20, MEP, LLR II latencies were measured, and the CRT was calculated for each limb. The statistical comparison between patients and controls was only weakly significant by taking into account conduction times along either the afferent (N20) or the efferent (MEP) pathways. On the contrary, it turned out to be considerably significant if both branches of the transcortical sensorimotor reflex arch, together with the intracortical pathway, were simultaneously tested by means of the LLRs. Moreover, the patients showed a significantly higher CRT compared with that found in the control subjects. These findings are consistent with a prolonged intracortical delay of LLRs in the MS group and suggest the occurrence of conduction velocity slowing and/or synaptic transmission impairment along the sensorimotor intracortical pathway in MS.

Support-specific modulation of grip force in individuals with hemiparesis

OBJECTIVE

To investigate whether use of auxiliary sensory input will result in modulated grip force.

DESIGN

Case-control study.

SETTING

Free-standing acute inpatient rehabilitation hospital.

PARTICIPANTS

Six people with unilateral hemiparesis due to unilateral stroke and 6 control subjects without neurologic disorders.

INTERVENTIONS

Seated subjects lifted and transported the same object under 3 different conditions: with no support, with the target arm positioned on a freely moving skateboard, and with a finger from the subject's contralateral hand lightly touching the wrist of the target arm.

MAIN OUTCOME MEASURES

Peak grip force and temporal coupling between the grip force and lift-off of the object.

RESULTS

All subjects were able to better regulate grip force when provided with additional sensory input. Light finger touch resulted in decreased grip force, as did skateboard use ( P <.05). Subjects with hemiparesis showed 2 times longer latency between grip-force application and lift-off of the object ( P <.05).

CONCLUSIONS

Statistically significant grip-force reduction was noted with both support aids. These findings could have implications in clinical and rehabilitative areas.

The cutaneous contribution to adaptive precision grip

Only after injury, or perhaps prolonged exposure to cold that is sufficient to numb the fingers, do we suddenly appreciate the complex neural mechanisms that underlie our effortless dexterity in manipulating objects. The nervous system is capable of adapting grip forces to a wide range of object shapes, weights and frictional properties, to provide optimal and secure handling in a variety of potentially perturbing environments. The dynamic interplay between sensory information and motor commands provides the basis for this flexibility, and recent studies supply somewhat unexpected evidence of the essential role played by cutaneous feedback in maintaining and acquiring predictive grip force control. These examples also offer new insights into the adaptive control of other voluntary movements.

The aging hand

Hand function decreases with age in both men and women, especially after the age of 65 years. A review is presented of anatomical and physiological changes in the aging hand. The age-related changes in prehension patterns (grip and pinch strength) and hand dexterity in the elderly population are considered. Deterioration in hand function in the elderly population is, to a large degree, secondary to age-related degenerative changes in the musculoskeletal, vascular, and nervous systems. Deterioration of hand function in elderly adults is a combination of local structural changes (joints, muscle, tendon, bone, nerve and receptors, blood supply, skin, and fingernails) and more distant changes in neural control. These age-related changes are often accompanied by underlying pathological conditions (osteoporosis, osteoarthritis, rheumatic arthritis, and Parkinson's disease) that are common in the elderly population. Assessment of hand function and prehension patterns is needed in order to determine specific treatment approaches.