Cognitive Functions, Schizophrenia
Conditions
Brief summary
The study will investigate the (1) additive and synergistic effects of tDCS and aerobic exercise on cognitive function and clinical symptoms in schizophrenia, and (2) neurophysiological mechanisms (mediators) underlying these effects.
Interventions
BEHAVIORALAerobic exercise
Aerobic exercise training will be conducted twice per week, over a period of 6 weeks, supervised by a well-trained facilitator. Each 45-minute session consists of a warm-up (10 minutes), treadmill walking (15 minutes), stationary bike cycling (15 minutes), and cool-down stretching (5 minutes). Heart rate will be monitored throughout training by a wearable device, and 60% of the maximum heart rate (roughly calculated by 220-age) should be maintained for at least 20 minutes during each session. Participants may stop exercising at any time if they feel uncomfortable.
DEVICEActive tDCS
Active tDCS will be applied using a wearable stimulator (Liftid) at a constant stimulation intensity of 1.2 mA for 20 minutes. The device has been designed for anodal stimulation targeting the dorsolateral prefrontal cortex (DLPFC) using the F3 (anode) to F4 (cathode) montages.
DEVICESham tDCS
Sham tDCS will be performed using the same device but without stimulation. During the aerobic exercise training, all participants will wear the device, and a facilitator will turn on the stimulation for participants receiving a-tDCS+AE intervention, and pretend to turn on the stimulation for participants receiving s-tDCS+AE intervention after the first 10-minute warm-up section.
Sponsors
The Hong Kong Polytechnic University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
* Schizophrenia spectrum disorders; * Aged from 18 to 65. * Chinese-speaking (to enable cognitive testing). * Ability to understand the nature of the study and to give informed consent. * Fewer than 10 hours of physical exercise in the previous 3 months.
Exclusion criteria
* Severe physical illness (Myocardial Infarction, Hypertension, Fracture, Spinal problems in which exercise with mild-to-moderate intensity may be contraindicated). * Comorbid diagnoses of organic brain syndrome, substance misuse, history of epilepsy or seizure, intellectual disability, significant head trauma, active suicidal ideation or self-harm behaviors. * Known pregnancy, or other contraindication to tDCS or MRI (e.g., have a cardiac/heart pacemaker, brain aneurysm clips, any implanted metallic or electrical device, or any internal metal foreign objects).
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Hong Kong List Learning Test (HKLLT) | Baseline and after the 6-week interventions | A Chinese verbal memory test designed to assess the processes and organizational strategies involved in learning verbal information. The test consists of two different 16-item two-character Chinese word lists, namely the random and blocked conditions. Total learning score, short-term, and long-term memory will be recorded in both conditions. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Rapid Visual Information Processing (RVP) | Baseline and after the 6-week interventions | A measure of sustained attention. A white box is shown in the center of the screen, inside which digits from 2 to 9 appear in a pseudo-random order, at the rate of 100 digits per minute. Participants are requested to detect target sequences of digits (for example, 2-4-6, 3-5-7, 4-6-8). When the participant sees the target sequence, they must respond by selecting the button in the center of the screen as quickly as possible. The level of difficulty varies depending on whether the participant must watch for one- or three-target sequences at the same time. |
| Digit Span (DGS) | Baseline and after the 6-week interventions | A measure of verbal short-term and working memory. The participant will hear a sequence of digits and will immediately be prompted to verbally repeat it. If the participant responds correctly, the next trial presents a longer sequence. The task terminates when participants respond incorrectly on three occasions at a span length. |
| The Verbal Fluency Test (VFT) | Baseline and after the 6-week interventions | A measure of executive function. Participants have to name as many animals as possible in 60 seconds. |
| 6-Minute Walking Test | Baseline and after the 6-week interventions | A sub-maximal exercise test to assess the aerobic capacity and endurance. The subject has to walk as far as possible along a track for 6 minutes. |
| The Fatigue Assessment Scale (FAS) | Baseline and after the 6-week interventions | A 10-item self-report instrument that evaluates fatigue symptoms. |
| The sit-and-reach test | Baseline and after the 6-week interventions | A common measure of flexibility, specifically assessing the lower back and hamstring muscles. The subject is seated against the wall, arms outstretched towards the box. A sliding ruler is used to measure the position of the fingertips. |
| Standing Balance Test | Baseline and after the 6-week interventions | Give the subject a minute to practice their balancing before starting the test. Then ask the person to stand on one foot for as long as possible. The total length of time a person can stay in the balance position will be recorded. The timing stops when the elevated foot touches the ground or the person hops or otherwise loses their balance position. The test will be conducted with the person having their arms on their waist. Repeat the test on the other leg. |
| Positive and Negative Syndrome Scale (PANSS) | Baseline and after the 6-week interventions | Measuring symptom severity of patients with schizophrenia. It contains 33 items across three subscales (Positive, Negative, and General), rated from 1-7 on each item based on clinical interviews as well as reports from family members or primary care hospital workers. |
| Calgary Depression Scale (CDS) | Baseline and after the 6-week interventions | A 9-item scale to evaluate depression, rated from 0 to 3. |
| Magnetic Resonance Imaging (MRI) | Baseline and after the 6-week interventions | Both structural and resting-state functional MRI will be acquired on a 3 Tesla MRI scanner (Prisma, Siemens, Germany). For registration purposes, high-resolution T1-weighted anatomical images will be acquired during 3-D MP-RAGE (parameters: slice thickness=1mm, echo time=3.26ms, repetition time=2250ms, inversion time=900ms, flip angle=9°, in-plane voxel size 1×1 mm2, acquisition time=5 minutes). Functional scans (resting state) will use a gradient-echo echo-planar imaging (parameters: repetition/echo time=800/37ms; flip angle=52°; field of view=208mm; 2mm isotropic \[no gap\]; no. of dynamics=380, acquisition time=5 minutes). The resting fMRI scan will be repeated for 5 times with a total acquisition time of 25 minutes. |
Countries
Hong Kong
Contacts
CONTACTProf. Jessie LIN
Outcome results
None listed