Joan Vidal

Effectiveness of transcranial direct current stimulation and visual illusion on neuropathic pain in spinal cord injury

The aim of this study was to evaluate the analgesic effect of transcranial direct current stimulation of the motor cortex and techniques of visual illusion, applied isolated or combined, in patients with neuropathic pain following spinal cord injury. In a sham controlled, double-blind, parallel group design, 39 patients were randomized into four groups receiving transcranial direct current stimulation with walking visual illusion or with control illusion and sham stimulation with visual illusion or with control illusion. For transcranial direct current stimulation, the anode was placed over the primary motor cortex. Each patient received ten treatment sessions during two consecutive weeks. Clinical assessment was performed before, after the last day of treatment, after 2 and 4 weeks follow-up and after 12 weeks. Clinical assessment included overall pain intensity perception, Neuropathic Pain Symptom Inventory and Brief Pain Inventory. The combination of transcranial direct current stimulation and visual illusion reduced the intensity of neuropathic pain significantly more than any of the single interventions. Patients receiving transcranial direct current stimulation and visual illusion experienced a significant improvement in all pain subtypes, while patients in the transcranial direct current stimulation group showed improvement in continuous and paroxysmal pain, and those in the visual illusion group improved only in continuous pain and dysaesthesias. At 12 weeks after treatment, the combined treatment group still presented significant improvement on the overall pain intensity perception, whereas no improvements were reported in the other three groups. Our results demonstrate that transcranial direct current stimulation and visual illusion can be effective in the management of neuropathic pain following spinal cord injury, with minimal side effects and with good tolerability.

Bowel Dysfunction in Patients with Motor Complete Spinal Cord Injury: Clinical, Neurological, and Pathophysiological Associations

BACKGROUND:Abnormal bowel function is a key problem in patients with spinal cord injury (SCI). Previous works provided only partial information on colonic transit time (CTT) or anal dysfunction but did not identified a comprehensive neurogenic bowel pattern.AIM:To evaluate clinical, neurological, and pathophysiological counterparts of neurogenic bowel in patients with motor complete SCI.METHODS:Fifty-four patients (56% men, mean age 35 yr) with chronic motor complete SCI (mean evolution time 6 yr) were evaluated: 41% with injuries above T7 (>T7) and 59% with injuries below T7 (<T7); patients were also classified according to the presence or not of sacral spinal reflexes. Clinical assessment, total and segmental CTT quantification, anorectal function evaluation by manometry, intrarectal balloon distension, and surface electromyography were performed.RESULTS:Three different neuropathophysiological patterns were observed: Pattern A, present in >T7 injuries, characterized by very frequent constipation (86%) with significant defecatory difficulty and not very severe incontinence (Mean Wexner score 4.5); it was related to moderate delay in CTT (mainly in the left colon and recto-sigma), incapacity to increase the intra-abdominal pressure, and the absence of anal relaxation during the defecatory maneuvre; Pattern B, present in <T7 injuries with preserved sacral reflexes, characterized by not so frequent constipation (50%) but very significant defecatory difficulty and not very severe incontinence (Wexner 4.8); the pathophysiological counterpart was a moderate delay in CTT, capacity to increase intra-abdominal pressure, increased anal resistance during the defecatory maneuver, and presence of external anal sphincter (EAS) contraction when intra-abdominal pressure increased and during rectal distension; Pattern C, present in <T7 injuries without sacral reflexes, characterized by not very frequent constipation (56%) with less defecatory difficulty and greater severity of incontinence (Wexner 7.2); this was associated with severe delay in CTT (mainly in the left colon), capacity to increase intra-abdominal pressure, absence of anal resistance during the defecatory maneuver, and absence of EAS contraction when intra-abdominal pressure increased and during rectal distension.CONCLUSION:In patients with motor complete SCI, we were able to define three different neuropathophysiological patterns that are associated with bowel function abnormalities and clinical complaints; this might be of help when designing therapeutic strategies.

The effects of transcranial direct current stimulation with visual illusion in neuropathic pain due to spinal cord injury: An evoked potentials and quantitative thermal testing study

Neuropathic pain (NP) is common in spinal cord injury (SCI) patients. One of its manifestations is a lowering of pain perception threshold in quantitative thermal testing (QTT) in dermatomes rostral to the injury level. Transcranial direct current stimulation (tDCS) combined with visual illusion (VI) improves pain in SCI patients. We studied whether pain relief with tDCS + VI intervention is accompanied by a change in contact heat‐ evoked potentials (CHEPs) or in QTT.

Motor and gait improvement in patients with incomplete spinal cord injury induced by high-frequency repetitive transcranial magnetic stimulation.

OBJECTIVE To assess the effect of high-frequency repetitive transcranial magnetic stimulation (rTMS) on lower extremities motor score (LEMS) and gait in patients with motor incomplete spinal cord injury (SCI). METHOD The prospective longitudinal randomized, double-blind study assessed 17 SCI patients ASIA D. We assessed LEMS, modified Ashworth Scale (MAS), 10-m walking test (10MWT), Walking Index for SCI (WISCI II) scale, step length, cadence, and Timed Up and Go (TUG) test at baseline, after the last of 15 daily sessions of rTMS and 2 weeks later. Patients were randomized to active rTMS or sham stimulation. Three patients from the initial group of 10 randomized to sham stimulation entered the active rTMS group after a 3-week washout period. Therefore a total of 10 patients completed each study condition. Both groups were homogeneous for age, gender, time since injury, etiology, and ASIA scale. Active rTMS consisted of 15 days of daily sessions of 20 trains of 40 pulses at 20 Hz and an intensity of 90% of resting motor threshold. rTMS was applied with a double cone coil to the leg motor area. RESULTS There was a significant improvement in LEMS in the active group (28.4 at baseline and 33.2 after stimulation; P = .004) but not in the sham group (29.6 at baseline, and 30.9 after stimulation; P = .6). The active group also showed significant improvements in the MAS, 10MWT, cadence, step length, and TUG, and these improvements were maintained 2 weeks later. Following sham stimulation, significant improvement was found only for step length and TUG. No significant changes were observed in the WISCI II scale in either group. CONCLUSION High-frequency rTMS over the leg motor area can improve LEMS, spasticity, and gait in patients with motor incomplete SCI.

Incidence of skeletal fractures after traumatic spinal cord injury: a 10-year follow-up study:

Objective: To analyse the incidence and factors related to the development and clinical evolution of fractures in patients with traumatic spinal cord injury. Design: A retrospective 10-year follow-up study. Setting: Neurorehabilitation centre. Subjects: Sixty-three patients (50M/13F) with a mean age of 36 ± 20 years with recent traumatic spinal cord injury attended over a one-year period (January to December 2000). Main measures: Medical reports were reviewed, evaluating risk factors for osteoporosis, fracture incidence during the 10 years following spinal cord injury, severity (ASIA score) and level of spinal cord injury (paraplegia/tetraplegia), type of lesion (spastic/flaccid), weight-bearing standing activity, and the cause, location and evolution of the fracture. Results: Of the 129 patients attending during the study period, 75 had traumatic spinal cord injury (7 died and 5 had no follow-up). Finally, 63 patients were included. Fifty-four per cent had complete motor injury (ASIA A). Twenty-five per cent of these patients developed fractures, with 2.9 fractures per 100 patient-years. The femur was the most frequent location of the fractures. Fractures were observed 6.4 ± 2.4 years after spinal cord injury (range 2–10 years), all in males. Most fractures (70%) were related to low-impact injuries. Fifty per cent presented with associated clinical complications and only 20% of the patients had received anti-osteoporotic treatment. Spinal cord injury severity was the only risk factor for the development of fractures (complete spinal cord injury (ASIA A)) (RR 4.043; 95% confidence interval (CI) 1.081–23.846, P = 0.037). Conclusion: The incidence of fractures after spinal cord injury is high, with severity and time since spinal cord injury being the main determinants for their development. Fractures were frequently associated with clinical complications. However, the use of anti-osteoporotic treatment was uncommon.

RETRACTED: Effects of High-Frequency Repetitive Transcranial Magnetic Stimulation on Motor and Gait Improvement in Incomplete Spinal Cord Injury Patients:

Kumru H, Benito J, Murillo N, et al. Effects of high-frequency repetitive transcranial magnetic stimulation on motor and gait improvement in incomplete spinal cord injury patients. Neurorehabil & Neural Repair. 2013;27:421-429. Original DOI: 10.1177/1545968312471901. The above article has been retracted because of substantial overlap with a previously published article in another journal.

Urethral Sphincter EMG as Event Detector for Neurogenic Detrusor Overactivity

The aim of this study was to investigate the feasibility of using external urethral sphincter electromyogram (EMG) (EUSEMG) to detect the onset of detrusor contractions in patients with both neurogenic detrusor overactivity (NDO) and detrusor sphincter dyssynergia (DSD). Detrusor pressure (Pdet) and EUSEMG was recorded in 23 neurogenic patients during slow artificial bladder filling. The time delay between the onset of EUSEMG detrusor contraction and the onset of activity was calculated together with the detrusor pressure increase related to this delay. Of 23 patients enrolled, 12 patients showed both NDO and DSD. Of these 12 patients, 10 had a strong correlation between detrusor pressure and EUSEMG . One patient in this group was excluded due to a storage pressure above 30 cmH2O . Two detection methods were applied on the remaining 9 patients. Method 1 was a root mean square (RMS)-integrator with simple thresholding. This approach had a good sensitivity but also a poor specificity (many false-positive detections). Detection method 2 included a kurtosis-based scaling function, which was multiplied to a similar RMS-integrator as used in method 1. Onset detection occurred before Pdet exceeded 18 cmH2O with both methods. However, method 1 resulted in 14.1plusmn12.8 false-positive detections during one bladder filling.Pdet at onset detection was on average 1.0plusmn1.1 cmH2O higher with detection method 2 but the number of false-positives was reduced by 95.8%. This paper demonstrates the feasibility of using EUSEMG to estimate the onset of a detrusor contraction in selected patients.

Evoked potentials and quantitative thermal testing in spinal cord injury patients with chronic neuropathic pain

OBJECTIVE Neuropathic pain (NP) is a common symptom following spinal cord injury (SCI). NP may be associated with altered processing of somatosensory pathways in dermatomes rostral to the injury level. To explore this possibility, the characteristics of contact heat evoked potentials (CHEPs) and quantitative thermal testing (QTT) were studied at and above the lesion level in SCI patients with NP. The goal was to determine processing abnormalities correlated with data from clinical evaluations. METHODS Thirty-two subjects with chronic NP, 22 subjects without NP and 16 healthy control subjects were studied. Warm and heat pain thresholds were determined both at and above SCI level. CHEPs were recorded above SCI level and subjects rated their perception of evoked heat pain using a numerical rating scale. RESULTS CHEPs were not different between the three groups. Evoked pain perception in SCI subjects with NP was significantly higher than in SCI subjects without NP and healthy controls. Heat pain threshold was significantly lower in subjects with NP in comparison to both groups. CONCLUSIONS Our findings indicate that processing of somatosensory inputs from dermatomes rostral to the injury level is abnormal in SCI subjects with NP. SIGNIFICANCE SCI somatosensory processing alteration may contribute to the understanding of the mechanisms underlying NP and secondary changes to NP in SCI.

Alterations in Excitatory and Inhibitory Brainstem Interneuronal Circuits after Severe Spinal Cord Injury

Reorganization of the central nervous system following spinal cord injury (SCI) involves changes not only at the cortical level, but also at the level of the brainstem. To further understand changes in excitatory and inhibitory brainstem interneuronal circuits following SCI, we studied recovery curves of the blink reflex (BR) to paired suprathreshold stimuli at various intervals (160, 300, 500, and 1000 msec), and prepulse inhibition of the BR following right index finger stimulation 100 msec prior to supraorbital nerve stimulation. Both parameters were studied in patients with SCI without baclofen treatment (n = 19), in patients with continuous intrathecal baclofen (CITB) (n = 9), and in healthy controls (n = 13). R2 recovery, expressed as the ratio of R2 area following the second stimulus divided by the R2 area following the first stimulus, was significantly greater in SCI patients without baclofen compared to controls and patients with CITB at all intervals, while there was no difference between patients with CITB and controls. Prepulse inhibition of R2 was significantly less in patients without baclofen compared to patients with CITB and healthy controls. Our findings indicate enhanced excitability and reduced inhibition of brainstem interneuronal circuits in patients with SCI, that are restored in the presence of baclofen to levels comparable to controls. In conclusion, SCI patients show more extended alterations in brainstem circuitry than previously thought. Decreased GABAergic mechanisms seem to be related to both excitatory and inhibitory brainstem circuit alterations. Baclofen appears to effectively restore this decreased GABAeregic activity.

Brainstem reflexes are enhanced following severe spinal cord injury and reduced by continuous intrathecal baclofen.

Objective. Plastic changes in the human central nervous system can occur at multiple levels, including circuits rostral to the lesion level in spinal cord injury (SCI). GABA is the most important inhibitory neurotransmitter in the brain. The authors hypothesized that one of the consequences of plasticity in SCI patients could be enhancement of brainstem reflexes, and they investigated the effect of continuous intrathecal baclofen (CITB) on such enhancement. Methods. The authors studied the early ipsilateral component R1 and the late component R2 of the blink reflex (BR), jaw jerk, masseter silent period (MSP), and auditory startle response (ASR) in 9 SCI patients without baclofen and in 8 with CITB. Nine healthy volunteers served as controls. Results. The amplitude of R1 of BR was significantly smaller in patients with CITB than in the other groups. The area of R2 of BR and of the ASR recorded in the orbicularis oculi, sternocleidomastoid, and biceps brachii muscles were significantly larger in SCI patients without baclofen than in controls, whereas there was no difference between patients with CITB and controls. The MSP magnitude was significantly larger in patients with CITB as compared with those without baclofen. Conclusion. The enhancement of brainstem reflexes in SCI patients may be due to plastic changes at the brainstem level after SCI. The significant reduction in response size in patients with CITB in comparison with patients without baclofen suggests that the enhancement of brainstem reflexes may be due to decreased GABAergic activity and that CITB is effective in reducing abnormal brainstem hyperexcitability.