Psychogenic parkinsonism: a combination of clinical, electrophysiological, and [(123)I]-FP-CIT SPECT scan explorations improves diagnostic accuracy.

We evaluated the concordance between independent clinical, electrophysiological, and [(123)I]-FP-CIT SPECT scan explorations as a staged procedure for an accurate diagnosis in 9 patients referred with a diagnosis of suspected psychogenic parkinsonism. Three patients were reclassified as pure psychogenic parkinsonism (PP), 6 with a form of combined psychogenic parkinsonism and Parkinson's disease (PP + PD), and none with pure Parkinson's disease (PD). Electrophysiological recordings showed the characteristics of psychogenic tremor in 5 of 7 patients with tremor. In two of these 5, PD tremor was also recorded. SPECT scan results were abnormal in five of 9 patients. In one case of clinically suspected PP + PD, SPECT scan results were normal. Long-term follow-up supported the final diagnosis of PP (initial clinical misdiagnosis). Electrophysiology contributes to the clinical diagnosis of psychogenic tremor and may help confirm associated organic PD tremor. [(123)I]-FP-CIT SPECT is a robust test to ascertain dopaminergic denervation and increase the confidence of the clinical and electrophysiological diagnosis of associated PD. A combination of clinical, electrophysiological, and [(123)I]-FP-CIT SPECT scan explorations improves diagnostic accuracy in order to distinguish PP from PP + PD.