Long term (TEN YEARS) follow-up in a trembling patient with parkinsonian signs without dopaminergic denervation

Some patients presenting with Parkinson's disease (PD)-like features do not exhibit dopaminergic denervation, complicating clinical categorization. This case report describes a patient with a long-standing upper limb action tremor accompanied by parkinsonian signs, but without evidence of dopaminergic denervation, followed over an extended period of ten years. The case highlights the diagnostic challenges and underscores the importance of longitudinal observation in such atypical presentations. A 76-year-old man with tremor and parkinsonian features was followed for ten years with clinical observation, video recordings, kinematic movement analysis, and structural and functional neuroimaging, including DaT-SPECT. Clinical and kinematic evaluations revealed asymmetric upper limb action tremor, inconstant rest tremor, bradykinesia with sequence effect, re-emergent tremor, and progressive motor symptoms. Over time, tremor extended to cranial regions, and mild dystonic postures emerged. Structural neuroimaging ruled out secondary causes, and DaT-SPECT remained negative despite symptom progression. Dopaminergic therapy was ineffective, while propranolol and clonazepam provided partial relief. This case highlights that parkinsonian motor features - such as re-emergent tremor and bradykinesia with sequence effect - can manifest and progress over time in patients with tremor, even in the absence of dopaminergic denervation. These findings underscore the need for further research into the role of the dopaminergic system in trembling patients. Moreover, they emphasize the importance of long-term follow-up and the integration of biomarkers to enhance the characterization and diagnostic accuracy of tremor syndromes.