Clinical Trial Summary
The primary objective of this study is to apply a biomechanical system (the NeuroFlexor)
associated with the EMG recording to study the physiological mechanisms that contribute to
the regulation of muscle tone in healthy subjects and in patients with increased muscle tone.
A second fundamental objective of this study is to monitor over time the changes in muscle
tone that can be found physiologically in healthy subjects and pathologically in patients
with spasticy and/or rigidity. A further objective of this study is the quantitative
evaluation of the symptomatic effects of specific therapies in improving the impaired muscle
tone.
Clinical evaluation In this research project the investigators will recruit 20 patients with
upper limb spasticity (regardless of the underlying disease responsible for the spasticity),
20 patients with Parkinson's disease characterized by stiffness of the upper limbs and 20
healthy control subjects. Patients will be recruited from the IRCCS Neuromed Institute,
Pozzilli (IS). Participants will give their written informed consent to the study, which will
be approved by the institutional ethics committee of the IRCCS Neuromed Institute, in
accordance with the Declaration of Helsinki. All participants will be right-handed according
to the Edinburgh handedness inventory (EDI) (Oldfield, 1971). Parkinson's disease will be
diagnosed in accordance with the updated diagnostic criteria of the MDS (Postuma, RB et al.
Validation of the MDS clinical diagnostic criteria for Parkinson's disease. Mov. Disord. Off.
J. Mov. Disord. Soc. 33, 1601 -1608 (2018)., Nd). Clinical signs and symptoms of parkinsonian
patients will be evaluated using the Hoehn & Yahr scale (H&Y), UPDRS part III (Patrick et
al., 2001). The diagnosis of spasticity will be made through the neurological clinical
evaluation of the patients and on the basis of the specific clinical history of the various
pathologies underlying the spasticity itself (e.g. multiple sclerosis, stroke, spinal
injuries). Spasticity will be assessed with the Modified Ashworth Scale "(MAS) (Harb and
Kishner, 2021), the Modified Tardieu scale (MTS) (Patrick and Ada, 2006). Cognitive functions
and mood, in both pathological conditions, will be evaluated using the clinical Mini-Mental
State Evaluation (MMSE) scale (Folstein et al., 1975) and the Hamilton Depression Rating
Scale (HAM_D) ( Hamilton, 1967). No participant must report pain problems and / or functional
limitations affecting the upper limbs.
Exclusion criteria: - insufficient degree of passive wrist movement (<30 ° in flexion and <40
° in extension) - tension at rest during NeuroFlexor recordings - hand pathologies
(neurological or rheumatological) - upper limb fractures in the previous six months -
presence of peacemakers or other stimulators - pregnancy.
All patients, and the group of healthy control subjects will have comparable anthropometric
and demographic characteristics.
Experimental paradigm Participants will be seated comfortably, with the shoulder at 45 ° of
abduction, the elbow at 90 ° in flexion, the forearm in pronation and the dominant hand
placed on the platform of the Neuroflexor device. Participants will be instructed to relax
during the test session, which will consist of the passive extension of the wrist at 7
speeds, one slow (5 ° / s) and 6 rapid (50 ° / s, 100 ° / s, 150 ° / s, 200 ° / s, 236 ° / s,
280 ° / s). The total range of wrist movement will be 50 °, starting from an initial angle of
20 ° in palmar flexion up to 30 ° in extension. Before the start of the experiment,
participants will do practical tests in order to become familiar with the device. Two slow
and five rapid movements will be made for each speed. The different angular velocities of
wrist mobilization will be randomized. Slow movements will be performed before fast movements
with an interval of 10 seconds between each test. For each participant, a NC, EC and VC value
in Newton will be calculated by a dedicated software. The resistance profiles will also be
obtained when the device was running idle (without hand) to allow the biomechanical model to
isolate the forces originating from the hand from the intrinsic forces of the device. For
each movement, the corresponding surface EMG trace will have been recorded, by placing the
electrodes on the skin overlying the belly of the FRC and ERC muscles. An accelerometer,
fixed on the back of the hand of the limb to be examined, will be used to synchronize the
electromyograph with the NeuroFlexor. The EMG activity recorded by means of surface
electrodes with belly-tendon type mounting, will be amplified using the Digitimer, will then
be digitized at 5 kHz using the CED, and finally it will be stored on a computer dedicated to
offline analysis. EMG recordings will be made at 6 speeds, 50°/ s, 100°/ s, 150°/ s, 200 °/s,
236 °/s, 280 °/s. For each trace the following parameters will be analyzed: latency,
peak-to-peak amplitude and area of the EMG response.
