Event‐related evoked potential responses (P₃₀₀) following epidural methylprednisolone therapy in chronic low back pain patients

Abstract

SummaryP 300 event-related potentials were recorded in 12 patients with chronic low back pain following epidural methylprednisolone administration. The values of absolute peak latencies and amplitudes of P 300 were recorded before (baseline) and on the 5th and 10th days following epidural injection. Intensity of pain was also recorded using a 10-cm visual analogue scale score. The absolute peak latency of P 300 significantly decreased on the 5th and 10th days following epidural methylprednisolone (p < 0.001) when compared with baseline value. Visual analogue scores also decreased significantly (p < 0.001) after the 5th and 10th days of epidural methylprednisolone. These observations suggest that following epidural methylprednisolone administration in chronic low back pain patients, significant improvement in cognitive functions and pain relief go hand in hand.

Altered neurocognitive processing of tactile stimuli in patients with Complex Regional Pain Syndrome (CRPS)

“…A rationale for investigating the P300 is its potential as a robust biomarker of cognitive dysfunction. For example, EEG research in other clinical contexts has found that P300 marks cognitive dysfunction in chronic headache 11 , chronic lower back pain 12 , phantom limb pain 13 , schizophrenia 14 , disorders of consciousness 15 and dementia 16 . The P300 is thought to reflect cognitive updating processes that are sensitive to task demands (providing a marker of attentional resource allocation).…”

“…Of these patients, five had left arm, three had right arm and five had left leg affected respectively. The mean disease duration was 5.3 years (range [1][2][3][4][5][6][7][8][9][10][11][12][13][14].…”

Evoked potential monitoring in anaesthesia and analgesia

“…This is probably because such event-related potentials (ERP) require the attention of the subject. In a recent study, Tandon et al [28] observed an increase in the APL of the P300 component in chronic low-back pain patients which might be due to a delay in the sensory perceptive process in addition to the cognitive process in the cortex. Tandon et al also reported the presence of maladaptive cognition and cognitive-behavioural deterioration in chronic pain patients as their attention is focused exclusively on pain [27].…”

“…6). Since the clinical relief of low-back pain and improvements in cognitive function go hand in hand, it has been suggested that P300 ERP may be used as an objective parameter to assess pain relief in chronic low-back pain patients [28].…”

“…These are elicited only when the subject can distinguish one stimulus (target) from a group of other stimuli (non-targets). Because of the relationship between P300-ERPs or P3 ERPs and cognitive processes, P300-ERPs have been widely used to evaluate cognitive functions in ageing [26], in chronic pain syndromes [27], including low back pain [28] and in awakening from anaesthesia [29].…”