Biomechanical indicators of the hand and wrist based on activities
of daily living for functional assessment and clinical
rehabilitation
Abstract:
The hand and wrist
form a complex musculoskeletal system, with more than 25 degrees of
freedom (DoF) controlled by more than 38 muscles in the hand and
forearm that allow the manipulative capacity necessary to interact
with his physical environment and perform activities of daily living
(ADL), allowing the necessary autonomy for a full functional life.
There are different pathologies and injuries that can affect the
function of the hand, from occupational accidents and pathologies,
pathologies inherent to the degenerative process associated with the
time, to neurological diseases, generating a decrease in the ability
to carry out ADLs in greater or lesser extent. The list of hand and
wrist conditions is extensive: deformities, degenerative diseases,
neuronal disorders, infections, as well as neuronal diseases that
affect the motor system, such as multiple sclerosis, muscular
dystonia or stroke.
The WHO establishes that functional assessment should be objective
and performed according to the ability to perform ADLs. However,
current clinical and rehabilitation methods are very different. At a
clinical level, the pathology is evaluated with medical criteria,
reconstructive therapies are applied when possible, and
rehabilitative techniques are applied to recover mobility and
strength as much as possible, with the final goal of recovering the
function of the hand. But all this is done without an evaluation of
how the ability to perform ADLs is affected, nor are the
improvements achieved in these terms quantified. Quantitative
assessments are rarely applied, and are limited in most cases to
measurement of ranges of motion or maximal forces for cylindrical
grasp and lateral pinch. More rarely, dexterity tests (Nine-hole peg
test, Box and Block, etc.) developed for certain neurological
pathologies are used. However, the relationship between the results
of these tests and the actual ability to perform ADL is unknown, as
is the case with ranges of motion or grasp capabilities.
Electromyography (EMG) is used to record muscle activity, which
allows the electrical signal of the muscles to be collected. In
clinical assessment, EMG is used in the initial assessment and
during the recovery process, studying the degree of muscle
activation, comparing values with the healthy limb and by observing
muscle coordination. However, this evaluation is limited to the
study of static actions that require muscular effort of a postural
nature. For an assessment like the one suggested by the WHO, it
would be necessary to study different biomechanical parameters
(kinematics, muscle activity and strength) during the performance of
representative ADLs, in order to identify objective indicators that
quantify the real impact on the ability to perform ADLs. However,
this biomechanical characterization is complex, due to the
difficulty in obtaining and interpreting biomechanical measurements
of the hand during real tasks given the complexity of the structure
of the hand and its interaction with objects.
Thus, the proposed project aims to contribute to the search for
biomechanical indicators of functional normality based on the
ability to perform ADLs, both to assess the impact of the function
and to favor its rehabilitation. In the first place, the search for
objective biomechanical indicators that could be comparable between
patients, either directly or through the application of dimensional
reduction techniques, is proposed. The experimental part will focus
on validating muscle activation indicators by measuring EMG in
patients during representative ADL tasks. Secondly, indicators based
on the ability to exert force during the performance of different
movements or grasps will be sought, measuring it in both
populations: healthy subjects (to establish normal values) and
patients (to probe the goodness of its use to improve the functional
assessment). Third, the search for ADL-based kinematic indicators
for the wrist will be investigated. For this, the recordings will be
considered in patients with wrist pathology. Fourth, due to the
malformations of the hand suffered in certain pathologies, the
validation in patients of the current instrumented glove protocol
for the measurement of hand kinematics is also proposed.
