Investigating the Cognitive Source of Visual Working Memory Impairment in Schizophrenia

August 9, 2022 updated by: Wang Jiunn-Kae, Taipei Medical University Shuang Ho Hospital
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.

Study Overview

Status

Recruiting

Intervention / 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 Type

Interventional

Enrollment (Anticipated)

40

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

      • New Taipei City, Taiwan, 231
        • Recruiting
        • Taipei Medical University Shuang Ho Hospital
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

20 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

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 Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Active comparator Within group
This project will use the StarStim DC stimulator manufactured by Neuroelectrics that was imported with TFDA approval. At the beginning, the participants would be allowed to perform the task which would be followed by application of tACS. The tACS application would be comprised of sham vs active where the sham condition would be given for 30 seconds while the active session would be applied for 15 mins. In tACS, 1mA of theta (6Hz) tACS would be given at the right F4 and P4 electrodes (5*5 cm2, Sponstim® 25). After tACS, the participants would be asked to perform the same task again and the scores (before and after tACS) will be compared and analyzed statistically. Therefore, each patient will need to participate in 2 sessions (active vs. sham), and they will not know which day is which (randomized order).
In order to evaluate the working memory ability of schizophrenic participants, a task was designed that needs to be performed by them. Firstly, a stimulus of six different color circles of same size in a gray background would be given for 500ms. This would be followed by 2000ms delay phase and then a test array would be appeared. The test array would be exactly same to the stimulus array but with or without change in color of only one circle. The test array would appear on the screen till the participants record their response and they would be asked to respond if the test array matches to the stimulus or not.
Sham Comparator: Sham comparator Within group
This project will use the StarStim DC stimulator manufactured by Neuroelectrics that was imported with TFDA approval. At the beginning, the participants would be allowed to perform the task which would be followed by application of tACS. The tACS application would be comprised of sham vs active where the sham condition would be given for 30 seconds while the active session would be applied for 15 mins. In tACS, 1mA of theta (6Hz) tACS would be given at the right F4 and P4 electrodes (5*5 cm2, Sponstim® 25). After tACS, the participants would be asked to perform the same task again and the scores (before and after tACS) will be compared and analyzed statistically. Therefore, each patient will need to participate in 2 sessions (active vs. sham), and they will not know which day is which (randomized order).
In order to evaluate the working memory ability of schizophrenic participants, a task was designed that needs to be performed by them. Firstly, a stimulus of six different color circles of same size in a gray background would be given for 500ms. This would be followed by 2000ms delay phase and then a test array would be appeared. The test array would be exactly same to the stimulus array but with or without change in color of only one circle. The test array would appear on the screen till the participants record their response and they would be asked to respond if the test array matches to the stimulus or not.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
VWM dysfunction
Time Frame: 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.
up to one hour

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Anticipated)

August 11, 2022

Primary Completion (Anticipated)

July 31, 2023

Study Completion (Anticipated)

July 31, 2023

Study Registration Dates

First Submitted

August 9, 2022

First Submitted That Met QC Criteria

August 9, 2022

First Posted (Actual)

August 11, 2022

Study Record Updates

Last Update Posted (Actual)

August 11, 2022

Last Update Submitted That Met QC Criteria

August 9, 2022

Last Verified

August 1, 2022

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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