Investigating the Cognitive Source of Visual Working Memory Impairment in Schizophrenia

Not Applicable

Completed

• Conditions: Memory Deficits Schizophrenia Neurostimulator; Complications

• Registration Number: NCT05496413
• Lead Sponsor: Taipei Medical University Shuang Ho Hospital

Brief Summary

The investigators plan to investigate the effect of enhancement on visual working memory (VWM) in patients of chronic schizophrenia and determine the predictive factors of effective treatment.

Detailed Description

Schizophrenia is a complex neuro-psychiatric disorder that affects a significant portion of total population worldwide. The disease impairs multiple aspects of human cognition, of which visual working memory (VWM) impairment is known to be one of the pivotal cognitive dysfunction in schizophrenic patients. Despite of several attempts that have been made to establish competent treatment strategies to impede cognitive dysfunction of schizophrenia, till date no such studies exhibited satisfactory outcomes. In this context, numbers of studies have been carried out to utilize transcranial direct current stimulation (tDCS) as a treatment option to enhance working memory deficit in various neuropsychiatric populations, but with very limited success. To this end, the present proposal will focus on the use of transcranial alternating current stimulation (tACS) to better target the oscillatory mechanisms underlying VWM. Our specific aims are twofold, namely, 1) Does DLPFC tACS work on schizophrenic patients in terms of VWM improvement, and 2) how is tACS facilitating patients' VWM? This is because VWM deficit can be caused by poor encoding, poor maintenance, or poor retrieval (or any combination between them). Failure at any of those steps will make the patients appear to have poor VWM from clinical observation, but the cognitive process that is impaired may not be the same across populations.

Study Timeline

• Study First Submitted: 2022-08-09
• Study First Submitted QC: 2022-08-09
• Study Start: 2022-08-11
• Study First Posted: 2022-08-11
• Primary Completion: 2023-09-12
• Study Completion: 2023-09-25
• Status Verified: 2024-09
• Last Update Submitted: 2024-09-26
• Last Update Posted: 2024-09-30

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 40

Inclusion Criteria

1. Inform consent acquired
2. Age 20 to 65
3. Right-handed
4. Patients with schizophrenia diagnosed according to DSM-5 criteria

Exclusion Criteria

1. Participants who are pregnant or breastfeeding
2. Participants who have metal implants
3. Participants who have alcohol/substance use disorder or received electro-convulsive therapy within the past 6 months.
4. Participants who have history of head injury with loss of consciousness
5. Participants who have history of brain lesions, infection, or epilepsy
6. Skin lesions on the electrodes placed
7. Cancer patients
8. Patients with high fever
9. Patients with significant sensory loss

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Primary Outcome Measures

Name	Time	Method
VWM dysfunction	up to one hour	Using the VWM task, investigate at which time point (encoding stage, maintenance stage, or retrieval stage) is VWM dysfunction occurring in schizophrenia patients.

Trial Locations

Locations (1)

Taipei Medical University Shuang Ho Hospital; 🇨🇳 New Taipei City, Taiwan