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Similar association between objective and subjective symptoms in functional and 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.

      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.

      Keywords

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