A 52-year-old man with Parkinson disease for 17 years came to our service with a 1-month history of sudden-onset resting tremor in the left upper limb only when lifting the contralateral limb (Video, segment 1). Four years prior, because of his motor fluctuations, he had deep brain stimulation (DBS) of the subthalamic nucleus implanted (St Jude Medical Libra XP), with good symptomatic control. During rest, despite signs of parkinsonism (bradykinesia and rigidity), no tremor was evident. When he moved the implantable pulse generator, the tremor reemerged (Video, segment 2). At the time, his medication regimen included only levodopa, 200 mg, 5 times a day every 2.5 hours. The impedance of the DBS system revealed high values in all contacts of the right electrode. However, examination and a series of plain radiographs did not reveal macroscopic defects (Figure). Dynamic disconnection in the pulse generator was suspected, and the DBS system was revised. During the review, a misconnection was found between the connection cable and the implantable pulse generator. After surgery (implantable pulse generator exchange), the patient showed immediate improvement.
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França C, Duarte KP, Cury RG. Dynamic Tremor in a Patient With Parkinson Disease. JAMA Neurol. 2021;78(8):1015. doi:10.1001/jamaneurol.2021.1431
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