A Randomized Controlled Neurophysiological Study of Qigong in Elderly With Depression

Change in executive function as assessed by Cambridge Neuropsychological Test Automated Battery (CANTAB®)

时间窗: Changes in time points: Baseline, at the end of the 8 weeks, 1 months after treatment

The CANTAB, a computerised battery of neuropsychological tests, assesses behavioral changes in executive functioning. A test battery that assesses cognitive safety (Roiser et al. 2016) would be used in this study to tap into some of the key cognitive domains. This battery includes four neuropsychological tests which are the (a) Reaction Time (RTI; assesses processing speed and psychomotor speed), (b) Paired Associates Learning (PAL; assesses visual memory and new learning), (c) Spatial Working Memory (SWM, a measure of strategy as well as working memory errors; executive function) and (d) Rapid Visual Information Processing (RVP; assess sustained attention). Also, an emotion recognition task (ERT) which measures the ability to identify emotions in facial expressions will be added to the cognitive safety battery. Six basic emotions will be covered. The total accuracy rate as well as the subscores for different emotions will be recorded to indicate basic emotion recognition ability.

Change in cognitive function as assessed by Attention Network Test

时间窗: Changes in time points: Baseline, at the end of the 8 weeks, 1 months after treatment

To evaluate the therapeutic effects of qigong on cognitive functions, we assess a range of cognitive functions including attention, inhibition, and executive function: Attention Network Test (ANT). The ANT is a variation from the Flanker test which assesses the efficiency of an individual's subsystems of attention (i.e. alerting, orienting, executive attention). The participants' task is to identify the direction of the central arrow by looking towards the corresponding direction, where either an upward or downward arrow will be presented. The difference of performance between the congruent and incongruent conditions represents inhibitory control ability. Neutral trials will also be presented for measuring simple attention.

Change in cognitive function as assessed by verbal fluency task (VFT)

时间窗: Changes in time points: Baseline, at the end of the 8 weeks, 1 months after treatment

Verbal fluency task (VFT). Executive functions are measured using the VFT. The experimental design of this task is adapted from previous fNIRS studies of verbal fluency where task blocks were interleaved with control blocks. Participants are required to generate exemplars of two semantic categories (i.e., animal and means of transportation) as many as possible, each for one minute, during the task blocks. This experimental task will begin with a 30-second phrase repetition period as a control, followed immediately by a 60-second task period (i.e, animal words), a 60-second control period, another 60-second task period (i.e., transportation words), and ended with another 60-second control period. The total measurement period is 270 seconds. The total number of correct and unique responses will be computed to reflect their fluency ability.

Change in cognitive function as assessed by N-back Task

时间窗: Changes in time points: Baseline, at the end of the 8 weeks, 1 months after treatment

N-back Task. The N-back paradigm that assesses the updating of working memory is adapted and modified from previous neurophysiological studies that consists of 0-back (i.e., low working memory load), and 2-back (i.e., high working memory load) conditions. Each condition will be presented two times and the tasks will be performed alternately in blocks, separated by a 25-35 seconds rest block during which the participants will be instructed to relax and sit still. The order of the two task blocks will be randomized across participants to avoid order effects, and no condition will be repeated consecutively. Each target (a digit) is presented for 500 milliseconds, followed by an interstimulus interval of 1500 milliseconds. Each task block lasts for 45 seconds, and the total duration of the paradigm is 8 minutes. The accuracy rate and RT of this task will be calculated to reflect the capacity of working memory and processing speed.

Hemodynamic changes as assessed by functional near-infrared spectroscopy (fNIRS)

时间窗: Changes in time points: Baseline, at the end of the 8 weeks, 1 months after treatment

fNIRS is a non-invasive neuroimaging procedure used to measure hemodynamic changes, in terms of oxyhemoglobin (HbO), deoxyhemoglobin (HbR) and total hemoglobin (HbT), associated with neuronal activities of the cerebral cortex in response to attending a task within the given period of time. Optical signals will be recorded on a two-wavelength (780 and 850 nm), continuous-wave optical imaging system (NIRSIT; OBELAB Co., Seoul, South Korea). The 48 channels with a 30-mm source-detector separation which cover the entire PFC area will be used in this study. In accordance with the international 10-20 EEG system, the center of the bottom probe row will be placed at the reference point Fpz. Consequently, channel 1 to channel 16 represent the right PFC, channel 17 to channel 32 the medial PFC, and channel 33 to channel 48 the left PFC. In addition, NIRSIT has an embedded gyroscope that enables online removal of motion artifacts.