Neuronal activation by electrical neuromuscular stimulation in hemiplegic patients demonstrated with 99m-Tc-ECD brain SPECT

Electrical neuromuscular stimulation (ENS) has been shown to improve volitional movement of upper limbs and decrease muscle hypertonia in hemiplegic patients. Aim: The purpose of this study was to demonstrate regional cerebral perfusion changes secondary to neuronal activation after ENS using 99mTc-ECD SPECT and to correlate these findings with clinical improvement. Materials and Methods: Nine hemiplegic and 3 paraparetic patients, with 14 to 59 years of age, 10 males and 2 females, were studied. ENS was performed for 14 weeks in 45-minute sessions on the muscles involved in hand opening and closing. Each patient was submitted to neurological examination before and after treatment and underwent three 99mTc-ECD SPECT studies: a pre-treatment study; a study performed during the first ENS session; and the third study during the last ENS session (after 14 weeks of treatment). Visual analysis of brain SPECT images was performed by two experienced nuclear physicians. Region-to-pons ratio (R/PO) was obtained for 15 brain regions. An asymmetry index (AI) was also calculated for all regions using the equation: AI=2X(R-L)/(R+L), where R is right and L is left. The visual and semi-quantitative results were compared in the three studies. Results: Visual analysis revealed perfusion improvement mainly in areas adjacent to the brain lesion (penumbra) but also in the contra-lateral cerebral hemisphere. Perfusion improvement was found in the frontal lobe (5 patients), fronto-parietal (1), fronto-temporal (1), temporal (2), basal ganglia (5) and in the thalami (1). In the pre-treatment study, 8 patients showed cerebellar diaschisis, which decreased during treatment in 2 patients and increased in 2. The asymmetry index showed significant variability among the three studies in 8 regions. The R/PO ratio did not correlate with the visual analysis. Neurological examination showed significant improvement in 10 patients, 9 of which showed perilesional brain perfusion improvement. Conclusion: Brain perfusion changes secondary to neuronal activation after ENS did occur in some cortical areas of both cerebral hemispheres and in the cerebellum and could be visually demonstrated with 99mTc-ECD SPECT. Brain SPECT imaging seems a promising tool for the investigation of these patients and for a better understanding of the neuronal activation phenomenon that occurs in their treatment