Postural sway in patients with early Parkinson’s disease performing cognitive tasks while standing

ABSTRACT

Objectives: We investigated postural sway in patients with early Parkinson’s disease (PD) to test the hypothesis that the postural control system was affected already at an early stage of PD. Moreover, we identified cases of dysfunction of stereopsis in PD patients.

Methods: We examined 23 patients with early PD and 23 healthy, sex- and age-matched control subjects. Postural sway was measured with an accelerometer at the center of mass at the lower spine. Subjects were asked to stand quietly for 30 s under two usual conditions (eyes open and eyes closed) and two dual tasks conditions (eyes open with dual task, eyes closed with dual task). Stereopsis was assessed using the Titmus fly test.

Results: In the usual conditions, no differences were found between the control group and PD group. With increasing task difficulty, PD patients showed an increase of RMS values of sway acceleration, compared to control subjects. These differences reached significance during cognitive task performance. PD patients showed larger JERK values with increasing difficulty of the sway task which also reached significance during cognitive task performance. Relative to controls, PD patients showed decreased stereopsis function. But, there were no statistically significant correlations between log seconds of arc of the Titmus test and JERK, even during cognitive task performance.

Conclusion: Our results indicate that patients with early PD have subtle signs of postural instability when their attention is diverted or reduced. In addition, deficits of stereopsis may be common in early PD patients. St

Abbreviations: ACC: Accelerometers; ANOVA: Analysis of variance; AP: Antero-posterior; COP: Center of pressure; EC: Eyes closed; ECDT: eyes closed with dual task; EO: Eyes open; EODT: Eyes open with dual task; GDS: Geriatric depression scale; JERK: Jerkiness of sway; ML: Medio-lateral; MMSE: Mini mental state examination; MoCA: Montreal cognitive assessment; PD: Parkinson’s disease; PDAbS: PD Patients with abnormal stereopsis; PDNrS: PD Patients with normal stereopsis; PIGD: Postural instability and gait disorder; RMS: Root mean square; UPDRS: Unified Parkinson’s disease rating scale.

KEYWORDS:

• Parkinson’s disease
• postural instability
• stereopsis
• accelerometer

Acknowledgments

We thank all the participants, Xiaojuan Dan for recruiting subjects and data collection assistance, and Zhuqin Gu for technical assistance.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by grants from the Ministry of Science and Technology of the People’s Republic of China [2012AA02A514], the National Basic Research Development Program of China [2011CB504101], and the Beijing High Standard Health Human Resource Cultural Program in Health System [2009e1e12].

Notes on contributors

Tuanzhi Chen

Tuanzhi Chen Ph.D. in neurology, deputy director, Department of Neurology, Liaocheng People’s Hospital, China. He has rich clinical experience in the diagnosis and treatment of common diseases and difficult diseases in the Department of Neurology. He is good at stratified diagnosis and treatment of ischemic cerebrovascular disease, individualized treatment of Parkinson’s disease and sleep disorders, especially in the diagnosis of dizziness / dizziness. At present, his main research direction is the basic and clinical research on Parkinson’s disease.

Yan Fan

Yan Fan master of Neurology, chief physician of Department of Neurology, Liaocheng People’s Hospital, Liaocheng, China. He specializes in the diagnosis and treatment of ischemic cerebrovascular diseases, and the individualized treatment of Parkinson’s disease and dyskinesia. He currently focuses on the clinical diagnosis of dyskinesia.

Xianbo Zhuang

Xianbo Zhuang master of Neurology, chief physician of Department of Neurology, Liaocheng People’s Hospital, Liaocheng, China. He specializes in the diagnosis and treatment of hemorrhagic cerebrovascular diseases, and the individualized treatment of Parkinson’s disease and cognitive impairment. He currently focuses on basic and clinical studies of cognitive impairment.

Depeng Feng

Depeng Feng master of Neurology, chief physician of Department of Neurology, Liaocheng People’s Hospital, Liaocheng, China. He is good at diagnosis and treatment of central nervous system infection and individualized treatment of Parkinson’s disease. He currently focuses on basic and clinical studies of Parkinson’s disease.

Yanxiu Chen

Yanxiu Chen master of Neurology, deputy chief physician, Department of Neurology, Liaocheng People’s Hospital, Liaocheng, China. He specializes in the diagnosis and treatment of neuroimmunodeficiency diseases, individualized treatment of Parkinson’s disease and demyelinating diseases. He currently focuses on basic and clinical studies of neuroimmunodeficiency diseases.

Piu Chan

Piu Chan Ph. D. in neurology, director of neurobiology research, Xuanwu hospital, Beijing, China. He enjoys the special allowance of the State Council. He has been engaged in studies on Parkinson’s disease genetics, epidemiology and animal models for many years. The effect of dopamine neuron death, aging on dopamine neurons, genetic changes and the influence of individual genetic susceptibility on the incidence of Parkinson’s disease have been fruitful.

Yifeng Du

Yifeng Du Ph.D. in neurology, director of Neurology, Provincial Hospital Affiliated to Shandong University, Jinan, China. He has been working for the prevention and control of Alzheimer’s disease for a long time, as the head of the “Shandong Alzheimer’s disease science and technology innovation alliance” and “the construction of the early prevention and control platform for Alzheimer’s disease in Shandong”. He established the research cohort of Alzheimer’s disease in Shandong Province, and carried out the early diagnosis and early warning of Alzheimer’s disease in China.