Painful legs and moving toes syndrome evaluated through brain single photon emission computed tomography: a case series

Painful legs and moving toes (PLMT) syndrome is a clinical entity characterized by persistent pain in the feet or legs and involuntary movements of one or more toes. The precise patho-mechanisms of PLMT still remain unknown. Herein, we examined ten patients clinically identified with PLMT syndrome. All patients first presented persistent pain prior to the onset of motor symptoms. Each patient was examined by neurological investigation, neuro-imaging methods including brain magnetic resonance imaging (MRI) and electrophysiological methods. The brain single photon emission computed tomography (SPECT) images of eight patients indicated hypoperfusion of frontal lobes and cerebellum. The conjunction analysis of brain SPECT imaging data of all eight patients, using the 3D-SSP program, compared to 34 controls indicated significant hypoperfusion in the prefrontal cortical, occipital cortical, and cerebellar surfaces, and thalamus, and hyperperfusion in the surface of the anterior cingulate gyrus and parietal cortices including primary and secondary somatosensory cortices, bilaterally. These areas reflected on a part of the pain matrix. Other electrophysiological examinations did not indicate specific abnormalities to explain the patients’ symptoms. On treatment with clonazepam, four out of nine patients could resolve their foot-related motor symptoms, but not the sensory symptoms. Overall, their pain was an intractable and persistent symptom throughout their clinical course. Our study infers that PLMT syndrome is fundamentally a chronic pain disorder, possibly relating to the central sensitization, involving the region of a part of pain matrix. Further studies need to confirm our results by adding more patients.