Table 1.
Participant Description.
Fig 1.
A within-limb and an interlimb reflex evoked in a participant with SCI.
EMG was evoked in (A) the ipsilateral tibialis anterior and (B) contralateral wrist flexors with superficial peroneal nerve stimulation (within-limb and interlimb reflex respectively). The top trace in each panel depicts the rectified averaged EMG from the 30 trials of EMG rastered below. Latency, duration, peak and integrated EMG (shaded) were measured for each reflex as shown in A. Onset of stimulus train is indicated by the stimulus artefact and an arrow.
Fig 2.
Interlimb and within-limb reflexes with SPN stimulation.
EMG evoked by SPN stimulation in 8 ipsilateral muscles of a participant with SCI (A) and each of the 16 muscles (ipsilateral and contralateral) of one control participant (B,C). There were no responses present in contralateral muscles of the participant with SCI. Therefore, they are not shown. The top trace in each panel depicts the rectified averaged EMG from all of the trials of stimulation (n = 23) rastered below. In A, trials that included artefacts from cable movement were removed from the soleus records. Stimuli occurred at the onset of the stimulus artefact visible in each average.
Fig 3.
Interlimb and within-limb reflexes with RN stimulation.
EMG evoked by radial nerve stimulation in 16 muscles (8 muscles recorded ipsilaterally, 8 contralaterally) of a participant with SCI (A,B) and one control participant (C,D). The top trace in each panel depicts the rectified averaged EMG from all of the trials of stimulation (n = 30) rastered below. Stimuli occurred at the onset of the stimulus artefact visible in each average.
Fig 4.
Incidence of within-limb, interlimb, and muscle reflexes.
Incidence of limbs (left) and muscles (right) in which reflexes were evoked in participants with spinal cord injury (SCI) (filled bars; n = 17) and able-bodied (AB) control participants (open bars; n = 5) by SPN stimulation (A) and RN stimulation (B). Within-limb reflex data are shaded. Muscles from the arm are indicated by BB–biceps brachii, TB–triceps brachii, FCR–flexor carpi radialis, and ECR–extensor carpi radialis, and muscles from the leg are indicated by BF–biceps femoris, QUAD–quadriceps, TA–tibialis anterior, and SOL–soleus. ** indicates significant differences in incidence between within-limb and interlimb reflexes § indicates significant differences in incidence between SCI and AB control groups. * indicates a significant relationship between having a SCI and the outcome (assessed by logistic regression).
Table 2.
Incidence of within-limb and interlimb reflexes.
Fig 5.
Reflex latency, duration and mean EMG amplitude for all muscles.
Data (median ±IQ range) for reflex latency (A and D), duration (B and E) and mean amplitude (C and F) are shown for SCI (filled symbols) and control groups (open symbols). Data for each muscle in both the arm and leg on the ipsilateral (I) and contralateral (C) sides are shown in each panel for SPN (A-C) and RN (D-F) stimulation. The grey shaded box indicates the muscles with within-limb reflexes for SPN (left panels) and RN (right panels) stimulation. Arm muscles are indicated by BB–biceps brachii, TB–triceps brachii, FCR–flexor carpi radialis, and ECR–extensor carpi radialis, and leg muscles are indicated by BF–biceps femoris, QUAD–quadriceps, TA–tibialis anterior, and SOL–soleus. Interlimb reflexes termed ascending, descending and contralateral (contra) are also indicated.