Similar association between objective and subjective symptoms in functional and organic tremor. (July 2019)

• Record Type: Journal Article
• Authors: Kramer, Gerrit; Dominguez-Vega, Zeus T.; Laarhoven, Heleen SA.; Brandsma, Rick; Smit, Marenka; van der Stouwe, AM Madelein; Elting, Jan Willem J; Maurits, Natasha M.; Rosmalen, Judith GM.; Tijssen, Marina AJ.
• Is Part Of: Parkinsonism & related disorders. Volume 64(2019)
• Page Start: 2
• Page End: 7
• Publication Date: 2019-07
• Subjects: Functional movement disorder -- Tremor -- Actigraphy -- Self-report -- Ambulatory assessment; Parkinson's disease -- Periodicals; Movement disorders -- Periodicals; Movement Disorders -- Periodicals; Nerve Degeneration -- Periodicals; Nervous System Diseases -- Periodicals; Parkinson Disease -- Periodicals; Tremor -- Periodicals; Parkinson, Maladie de -- Périodiques; Parkinson's disease; 616.833
• DOI: 10.1016/j.parkreldis.2019.05.026
• Languages: English
• ISSNs: 1353-8020

Abstract

Abstract: Background: A previous study reported a dramatic mismatch in objectively detected and self-reported tremor duration in patients with functional tremor. As these findings have an important and widespread impact in both clinical care and research, we conducted a validation study with a longer study duration and a larger sample of patients. Methods: Fourteen patients with functional tremor and 19 with organic tremor completed a 30 day study period. Objective tremor duration was recorded using a wrist-worn accelerometer. Simultaneously, participants completed a web-based diary five times a day, each time rating their symptom burden since the previous diary entry. Results: Patients with functional tremor had shorter objective tremor duration compared to patients with organic tremor (21.6% vs 30.7%, P = 0.034). A post-hoc analysis revealed the difference in objective duration was mainly due to patients with essential tremor (37.2%). Subjective symptom burden was not significantly different between functional and organic tremors (38.7 vs 28.7 on a 0–100 VAS scale, P = 0.138). Finally, a mixed model analysis did not reveal significant differences in the association between subjective and objective tremor symptoms (P = 0.168). Conclusions: patients with functional tremor do have an objectively detectable, persistent tremor during daily life activities. Furthermore, they have a similar symptom burden and a similar association between subjective and objective tremor symptoms as patients with organic tremor. Highlights: Few studies tried to objectively quantify functional tremor in the home environment. We found a considerable level of objective tremor duration in functional tremor. Subjective symptom burden was similar in functional and organic tremor patients. Objective and subjective tremor symptoms had a similar association in both groups.