Diagnostic Uncertainties in Post-stroke Pain

Aim of Investigation Pain is a common complication after stroke. The etiology of post-stroke pain is largely unknown and classification of post-stroke pain subtypes is primarily based on neurological examination and pain assessment. Classification could probably be improved by a better understanding of the neurophysiological mechanisms underlying the pain complaints. We reviewed several neurological and neurophysiological correlates of post-stroke pain as reported in the literature from 1987 to 2007. Methods A total of twenty-one articles was reviewed on: 1) diagnostic criteria of central post-stroke (CPSP) and hemiplegic shoulder pain (HSP), 2) somatosensory and nociceptive dysfunction in pain-free (PF) patients and patients with CPSP or HSP, as determined with routine clinical examination, quantitative sensory testing and evoked potentials, and 3) the relationship between pain description and intensity as reported by the patients and somatosensory or nociceptive dysfunction. Results Several methods were reported for post-stroke pain classification, however, no gold standard could be found. No discriminating somatosensory or nociceptive profiles of post-stroke pain subtypes could be detected. Furthermore, the relation between the severity of dysfunction, pain severity and pain description remained unclear. Conclusions Currently, distinct neurological and neurophysiological features of post-stroke pain subtypes are lacking. Possibly, a more standardized description of neurological dysfunction and the use of more sophisticated techniques such as (laser) evoked potentials and functional magnetic resonance imaging, might contribute to an improved classification of post-stroke pain. Acknowledgments: We acknowledge the financial support of the St. Jorisstichting.