Thalamic pain syndrome of Dejerine-Roussy. Differentiation of four subtypes assisted by somatosensory evoked potentials data
F. Mauguiere and J. E. Desmedt
Department of EEG and Epileptology, Faculty of Medicine Lyon-Nord, France.
In 30 patients with a thalamic vascular lesion and clinical somatosensory
disturbances in the opposite hemibody without hemiplegia, four nosological
groups were identified: group 1 had no central pain but complete
hemianesthesia and loss of cortical somatosensory evoked potentials (SEPs)
on the affected side (analgic thalamic syndrome). Group 2 had central pain,
severe hypoesthesia, and loss of cortical SEPs. Group 3 had central pain
and hypoesthesia, with cortical SEPs present, although reduced or delayed
on the affected side. Group 4 had central pain with preserved touch and
joint sensations and normal SEPs (pure algetic thalamic syndrome). Clinical
signs and SEP titration of the actual involvement of lemniscal pathways in
these four groups of patients with thalamic syndrome are discussed in
relation to current pathophysiology of central pain.
