title: Tremor frequency characteristics in Parkinson's disease under resting-state and stress-state conditions.
abstract: Tremor characteristics-amplitude and frequency components-are primary quantitative clinical factors for diagnosis and monitoring of tremors. Few studies have investigated how different patient's conditions affect tremor frequency characteristics in Parkinson's disease (PD). Here, we analyzed tremor characteristics under resting-state and stress-state conditions. Tremor was recorded using an accelerometer on the finger, under resting-state and stress-state (calculation task) conditions, during rest tremor and postural tremor. The changes of peak power, peak frequency, mean frequency, and distribution of power spectral density (PSD) of tremor were evaluated across conditions. Patients whose tremors were considered more than "mild" were selected, for both rest (n=67) and postural (n=25) tremor. Stress resulted in both greater peak powers and higher peak frequencies for rest tremor (p<0.001), but not for postural tremor. Notably, peak frequencies were concentrated around 5 Hz under stress-state condition. The distributions of PSD of tremor were symmetrical, regardless of conditions. Tremor is more evident and typical tremor characteristics, namely a lower frequency as amplitude increases, are different in stressful condition. Patient's conditions directly affect neural oscillations related to tremor frequencies. Therefore, tremor characteristics in PD should be systematically standardized across patient's conditions such as attention and stress levels.
authors.affiliation: The Interdisciplinary Program for Bioengineering, Seoul National University, Seoul, Republic of Korea. Electronic address: hongjidan@bmsil.snu.ac.kr.
authors.forename: Hong Ji
authors.initials: HJ
authors.lastname: Lee
authors.affiliation: The Department of Neurology, Eulji General Hospital, Seoul, Republic of Korea.
authors.forename: Woong Woo
authors.initials: WW
authors.lastname: Lee
authors.affiliation: The Interdisciplinary Program for Bioengineering, Seoul National University, Seoul, Republic of Korea.
authors.forename: Sang Kyong
authors.initials: SK
authors.lastname: Kim
authors.affiliation: The Department of Neurology and Movement Disorder Center, Seoul National University Hospital, Seoul, Republic of Korea.
authors.forename: Hyeyoung
authors.initials: H
authors.lastname: Park
authors.affiliation: The Interdisciplinary Program for Bioengineering, Seoul National University, Seoul, Republic of Korea.
authors.forename: Hyo Seon
authors.initials: HS
authors.lastname: Jeon
authors.affiliation: The Interdisciplinary Program for Bioengineering, Seoul National University, Seoul, Republic of Korea.
authors.forename: Han Byul
authors.initials: HB
authors.lastname: Kim
authors.affiliation: The Department of Neurology and Movement Disorder Center, Seoul National University Hospital, Seoul, Republic of Korea.
authors.forename: Beom S
authors.initials: BS
authors.lastname: Jeon
authors.affiliation: The Department of Biomedical Engineering, Seoul National University College of Medicine, Seoul, Republic of Korea. Electronic address: pks@bmsil.snu.ac.kr.
authors.forename: Kwang Suk
authors.initials: KS
authors.lastname: Park
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications*; D012146:Rest / Q000502:physiology*; D013057:Spectrum Analysis; D013315:Stress, Psychological / Q000150:complications*; D014202:Tremor / Q000209:etiology*
keywords: Parkinson's disease; Tremor characteristics; Tremor frequency; neural oscillators; stress-state condition