title: Operculo-insular pain (parasylvian pain): a distinct central pain syndrome.
abstract: Central pain with dissociated thermoalgesic sensory loss is common in spinal and brainstem syndromes but not in cortical lesions. Out of a series of 270 patients investigated because of somatosensory abnormalities, we identified five subjects presenting with central pain and pure thermoalgesic sensory loss contralateral to cortical stroke. All of the patients had involvement of the posterior insula and inner parietal operculum. Lemniscal sensory modalities (position sense, graphaestesia, stereognosis) and somatosensory evoked potentials to non-noxious inputs were always preserved, while thermal and pain sensations were profoundly altered, and laser-evoked potentials to thermo-nocoiceptive stimuli were always abnormal. Central pain resulting from posterior parasylvian lesions appears to be a distinct entity that can be identified unambiguously on the basis of clinical, radiological and electrophysiological data. It presents with predominant or isolated deficits for pain and temperature sensations, and is paradoxically closer to pain syndromes from brainstem lesions affecting selectively the spinothalamic pathways than to those caused by focal lesions of the posterior thalamus. The term 'pseudo-thalamic' is therefore inappropriate to describe it, and we propose parasylvian or operculo-insular pain as appropriate labels. Parasylvian pain may be extremely difficult to treat; the magnitude of pain-temperature sensory disturbances may be prognostic for its development, hence the importance of early sensory assessment with quantitative methods.
authors: Central Integration of Pain Unit, U879 INSERM & University Claude Bernard, Lyon 1, Neurological Hospital, Lyon, France. larrea@univ-lyon1.fr
authors: Luis
authors: L
authors: Garcia-Larrea
authors: Caroline
authors: C
authors: Perchet
authors: Christelle
authors: C
authors: Creac'h
authors: Philippe
authors: P
authors: Convers
authors: Roland
authors: R
authors: Peyron
authors: Bernard
authors: B
authors: Laurent
authors: François
authors: F
authors: Mauguière
authors: Michel
authors: M
authors: Magnin
mesh_terms: D000328:Adult; D000344:Afferent Pathways / Q000473:pathology / Q000503:physiopathology; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000473:pathology* / Q000503:physiopathology*; D004569:Electroencephalography / Q000379:methods; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000473:pathology* / Q000503:physiopathology; D010147:Pain Measurement / Q000379:methods; D010812:Physical Stimulation / Q000379:methods; D012684:Sensory Thresholds / Q000502:physiology; D013697:Thermosensing / Q000502:physiology; D014110:Touch / Q000502:physiology*