Pain, 61 (1995) 177-186 177 © 1995 Elsevier Science B.V. All rights reserved 0304-3959/95/$09.50 PAIN 2664 Research Papers Sensory abnormalities in consecutive, unselected patients with central post-stroke pain Karsten Vestergaard a,*, Jesper Nielsen b, Grethe Andersen a, Margrethe Ingeman-Nielsen c, Lars Arendt-Nielsen b and Troels S. Jensen d Departments of a Neurology and c Radiology, Aalborg Hospital, DK-9100 Aalborg (Denmark) and b Department of Medical lnformatics, Aalborg University Center and d Department of Neurology, Aarhus University Hospital, Aarhus (Denmark) (Received 22 March 1994, accepted 29 June 1994) Summary This study examined the sensory abnormalities in an unselected, consecutive group of patients with central post-stroke pain (CPSP) surviving more than 1 year after stroke. The sensory examination included clinical examination and quantitative measures with detection and pain thresholds to heat and cold stimuli, argon laser, von Frey hair and determination of stimulus-response function in the 10-45°C range. Sensory examination was in 11 identified CPSP patients (5 female, 6 male; aged 43-80 years) carried out in the painful area using the contralateral homologue area as reference. Pain rating was performed using the McGill Pain Questionnaire and a VAS scale. All patients had ischemic (MRI verified) infarction. Of the 11 patients with supratentorial lesions, 5 had thalamic lesions; in addition, 7 patients had lesions in the brain stem/cerebellum. Median present spontaneous pain intensity on the VAS scale was 3.3 (range: 0-7.7). All patients had pain in the body part with sensory abnormalities, which in 8 patients extended the area with pain. Warm detection threshold was higher in the pain area in all patients, and all except 1 patient had increased cold detection threshold. Cold and heat pain thresholds were raised as well, but to a lesser degree. Sensibility to touch (von Frey hairs) and pain (argon laser) were changed in only 4 and 3 patients, respectively. A stimulus-re- sponse curve in the 10-45°C range showed different pattems compared to the non-affected side. A cold allodynia in the 10-45°C range was present in the painful area in 6 (56%) of the patients. The results support the theory that damage to the spino-thalamo-cortical pathway is a necessary condition in CPSP. It is proposed that the spontaneous pain in CPSP is linked to hyperexitability or spontaneous discharges in thalamic or cortical neurons that have lost part of their normal input. Key words: Central post-stroke pain; Quantitative measure; Spinothalamic function; Allodynia; Central hyperex- citability Introduction Central post-stroke pain (CPSP) is a neuropathic pain syndrome, where the vascular lesion is assumed to be responsible for the pain (Dejerine and Roussy 1906; Schott et al. 1986; Mauguire and Desmedt 1988; Boivie et al. 1989; Leijon et al. 1989; Lewis-Jones 1990; Boivie * Corresponding author: Dr. Karsten Vestergaard, Department of Neurology, Aalborg Hospital, P.O. Box 365, DK-9100 Aalborg, Denmark. Tel.: (45) 99-32-23-75; FAX: (45) 99-32-24-21. 1992). CPSP is characterized by pain in the body part corresponding to the entire or part of the cerebral lesion caused by the vascular accident. Although previ- ously considered to be a rare consequence of stroke, a new study (Andersen et al. 1994) has indicated an CPSP incidence of 8% among unselected stroke pa- tients. Since the original description by Dejerine and Roussy (1906) it has become known that the presence of sensory abnormalities is a characteristic feature of thalamic pain (a subgroup of CPSP). While the condi- tion originally described as thalamic pain by Dejerine and Roussy (1906) has previously been associated with SSDI 0304-3959(94)00140-5