Answers are grounded in this paper and cite their sources.
Two percent of normal controls noted that drinking coffee made their hands shaky. Eight percent of essential tremor and 6% of Parkinson's disease patients thought that coffee worsened their tremor. In formal tests, a single oral dose of caffeine (325 mg) did not increase physiologic, essential tremor, or parkinsonian tremor at 1, 2, or 3 hours after ingestion. Caffeine only infrequently induces tremor in normal people, and it does not exacerbate pathologic tremor.
No takes yet. Share an insight, caveat, or question.
Koller et al. (1987) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: