Is an Isolated Weight-Holding Tremor a New Subtype of Isometric Tremor?

A weight-holding tremor is a rare type of hand tremor that occurs only when someone holds some weight. Here we report three cases of isolated weight-holding tremors, of which one patient was diagnosed with Parkinson's disease (PD) and the others as a variant of essential tremor (ET). A 68-year-old woman presented with a left-hand tremor that appeared only when she held objects with some weight. Her tremor was reminiscent of the re-emergent tremor of PD, and dopamine transporter imaging revealed reduced uptake at the right posterior putamen. A 21-year-old man and a 71-year-old woman also presented with similar weight-holding tremors. However, these tremors were not re-emergent, and no signs of parkinsonism were observed during follow-up. Although the underlying etiologies of these tremors differed, all three tremors worsened as the held weight increased. These tremors could be isolated isometric tremors, but further research is needed to clarify the nature of this rare tremor.