Journal of Rehabilitation Medicine 51-4inkOmslag | Page 74

308 A. Chalard et al. METHODS Participants This pilot case-controlled prospective observational study included 10 adults with brain injury (HEMI) and 10 control participants (CONTROL) (see Table I for participants’ demo- graphics). The inclusion criteria were: brain injury for at least 6 months caused by an acquired cerebral lesion (single stroke or traumatic brain injury); strength of paretic triceps brachii (rated at least at 3/5 on the Held-Deseilligny Scale, corresponding to extension of the forearm against slight resistance); and no anti-spastic treatment during the 3 previous months. Exclusion criteria were: severe cognitive disorders with limited compre- hension of basic instructions; neurodegenerative conditions other than the acquired brain injury; elbow contracture (loss of passive elbow extension or flexion); and upper limb pain during movement. Ethics approval was obtained from the local institutional review board at Paul Sabatier University Hospital (No. 07-0716, Toulouse, France) and written informed consent was obtained from all participants. The study was conducted in accordance with the amended Declaration of Helsinki and conforms to all STROBE guidelines, reporting the required information accordingly. Materials Net torque around the elbow joint was recorded at 1 kHz using a Con-Trex MJ calibrated dynamometer (CMV AG, Dubendorf, Switzerland). The surface electromyographic signal (EMG) was recorded at 1 kHz using Ag–AgCl bipolar electrodes in bipolar confi- guration with an inter-electrode distance of 20 mm,, using an MP150 system (Biopac Systems Inc., Goleta, CA, USA). The reference electrode was placed on the left ulnar head. Biceps brachii and brachioradialis were selected as the elbow flexors acting as antagonist muscles during elbow extension. Recordings were made on the non-dominant side in the CON- TROL group and on the paretic side in HEMI group. Torque and EMG data were synchronized automatically using a rectangular triggering pulse signal and analysed offline. Procedure The experimental procedure comprised 2 steps. First step. To perform the following clinical assessment (7): spasticity of elbow flexors, limitation to active elbow extension, Fig. 1. Illustration of the arm and forearm positions used to perform torque and electromyographic recordings during isometric elbow extension on the calibrated dynamometer. motor selectivity and motor function were assessed respec- tively, using the Tardieu scale, a goniometer during repetitive and dynamic voluntary elbow extensions at a preferred rate, the upper limb motor section of the Fugl-Meyer Assessment scale, and the Action Research Arm Test (Table I). Maximal net elbow extension torque value was taken as a functional marker of triceps brachii paresis, the Fugl-Meyer score as a motor selectivity assessment, and the Action Research Arm Test as a motor function assessment. Second step. Participants were seated on the dynamometer chair with their upper body strapped firmly, the upper arm positioned along the trunk, and the elbow flexed at 90° (Fig. 1). The parti- cipants exerted 3 isometric maximal voluntary contractions of the elbow in flexion and in extension for a duration of 5 s, with 1 min rest between each contraction and 3 min rest between flexion and extension contractions. After collection of maximal voluntary contraction data, participants performed 2 sets of 5-s elbow isometric extension sub-maximal contractions while receiving visual feedback on their actual torque in relation to a target torque. Each set included 6 contractions at 25% Maxi- mal Voluntary Contraction (MVC), corresponding to a level of force required for daily activities (8). The time between each contraction was 30 s; each set was separated by a 3-min rest period to minimize fatigue. Table I. Participants’ demographics Fugl-Meyer Disease Assessment score Action Research course, month (upper limb/66) Arm Test (/57) – Participants Sex Control Group 6 Males 30 (15)* 4 Females – – Female Male Male Male Male Male Male Male Male Male Ischaemic stroke Haemorrhagic stroke Ischaemic stroke Ischaemic stroke Ischaemic stroke Ischaemic stroke Ischaemic stroke Traumatic brain injury Traumatic brain injury Haemorrhagic stroke Left, cortical & subcortical 48 Left, thalamic 14 Left, latero-bulbar 27 Left, subcortical 43 Left, cortical & subcortical 39 Right, cortical & subcortical 60 Right, cortical & subcortical 146 Left, cortical & subcortical 132 Right, cortical & subcortical 360 Left, subcortical 60 (n  = 10) Brain Injured Group 1 2 3 4 5 6 7 8 9 10 Age, year Pathology Side and location of cerebral injury 47 66 59 52 64 71 33 41 57 63 – – 55 51 59 48 60 44 54 46 18 32 39 36 55 18 57 23 51 29 0 0 *Mean (standard deviation (SD)), indicates a significant difference in age between HEMI and CONTROL groups (p  < 0.05). www.medicaljournals.se/jrm