ObjectivesSeveral recent studies report the presence of a specific EEG pattern named Thalamocortical Dysrhythmia (TCD) in patients with severe chronic neurogenic pain. This is of major interest since so far no neuroscientific indicator of chronic pain could be identified. We investigated whether a TCD-like pattern could be found in patients with moderate chronic back pain, and we compared patients with neuropathic and non-neuropathic pain components. We furthermore assessed the presence of psychopathology and the degree of psychological functioning and examined whether the strength of the TCD-related EEG markers is correlated with psychological symptoms and pain ratings.DesignControlled clinical trial with age and sex matched healthy controls.MethodsSpontaneous EEG was recorded in 37 back pain patients and 37 healthy controls.ResultsWe were not able to observe a statistically significant TCD effect in the EEG data of the whole patient group, but a subsample of patients with evidence for root damage showed a trend in this direction. Pain patients showed markedly increased psychopathology. In addition, patients' ratings of pain intensity within the last 1 to 12 months showed strong correlations with EEG power, while psychopathology was correlated to the peak frequency.ConclusionOut of several possible interpretations the most likely conclusion is that only patients with severe pain as well as root lesions with consecutive thalamic deafferentation develop the typical TCD pattern. Our primary method of defining ‘neuropathic pain’ could not reliably determine if such a deafferentation was present. Nevertheless the analysis of a specific subsample as well as correlations between pain ratings, psychopathology and EEG power and peak frequency give some support to the TCD concept.Trial RegistrationClinicalTrials.gov NCT00744575

Background: A pilot study of an 8-week mindfulness-based stress reduction (MBSR) program on a sample of low back pain patients was conducted in order to assess the feasibility and effectiveness of the intervention as well as changes in an EEG pattern called thalamocortical dysrhythmia which is associated with chronic pain. Patients and Methods: 22 patients with chronic low back pain participated in an MBSR program. Effect sizes were measured for psychological functioning, pain severity, and quality of life. Furthermore, 4 parameters of the EEG power spectral density were assessed. Results: Medium size effect sizes were found for health-related quality of life (EQ-5D, VAS, d = 0.43, p = 0.02; SF-12, psychological functioning, d = 0.50, p = 0.05), health-related life satisfaction (questions on life satisfaction d = 0.69, p = 0.01), depression (HADS, d = 0.48, p = 0.04, Brief Symptom Inventory d = 0.41, p = 0.04), and affective pain perception (pain perception scale d = 0.50, p = 0.04). The most relevant pain severity measurements improved in the range of d = 0.45-0.75 (p = 0.01-0.24). EEG analyses revealed no differences between the pre- and post-intervention. Conclusion: MBSR is a feasible intervention for patients with low back pain. They benefit from medium size effects which are comparable to similar behavioral interventions. Randomized controlled trials are needed in order to determine the specificity of these benefits.

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