Effects of tES Combined With Retrieval Practice on Semantic Memory in Patients With Schizophrenia

NCT ID: NCT06547996

Last Updated: 2024-11-15

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

72 participants

Study Classification

INTERVENTIONAL

Study Start Date

2024-08-30

Study Completion Date

2024-10-30

Brief Summary

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The semantic processing deficit stands as a central feature of cognitive abnormalities in schizophrenia. Both transcranial electrical stimulation (tES) and retrieval practice have been demonstrated as external techniques capable of ameliorating the semantic processing deficit in individuals with schizophrenia. The inquiry examines whether the combined effect of tES and retrieval practice, following tES intervention targeting the left dorsolateral prefrontal cortex (L-DLPFC) in patients with schizophrenia, contributes to the preservation of semantic memory in these individuals.

Investigators plan to recruit 60 patients diagnosed with schizophrenia from hospitals. Treatment is administered by two examiners, each patient receives transcranial electrical stimulation(2mA×20min) with simultaneous learning of word lists. Each participant of each stimulation type was involved in both learning conditions, meaning that all participants completed both retrieval and restudy learning and testing Subsequently, Investigators observed their immediate and delayed memory performance through tests.

Detailed Description

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1. Stimulation phase:

In the tDCS group, the anode was placed over the left DLPFC (F3), and the cathode was placed over the contralateral supraorbital area (FP2). A direct current of 2mA was applied for 20 minutes during each stimulation session. In the tACS group, the anode was placed in the F3 region of the left dorsolateral prefrontal cortex (DLPFC), and the cathode was placed in the right supraorbital region (Fp2), and the current used was 2 mA AC at 40 Hz, with a stimulation time of 20 min. In the sham group, the stimulation parameters, including the stimulation site and duration, were identical to those of the anodal group. However, during the 10-second ramp-up and ramp-down periods before and after stimulation, patients were unaware that the current was turned off.
2. Learning phase:

The experimental procedure followed the classic retrieval practice paradigm, which included a learning phase and a final test phase.

During the experiment, participants were informed that they would learn two lists of words. Subsequently, they might either learn the words again or complete a list recall test, and will be given a final test shortly thereafter. The learning of the retrieval practice list and the restudy list was conducted in a randomly balanced manner. Each word was presented for 5 seconds, with a 500-millisecond interval between words. To avoid providing secondary retrieval cues between examples, all words were shuffled pseudo-randomly within categories. Each list contained 17 words, consisting of 5 examples from each of the 3 experimental categories (15 experimental examples, 2 filler examples). The first and last words presented in each list were filler words, thus controlling for the primacy and recency effects on memory.

For the retrieval practice list, participants underwent two learning sessions and two retrieval sessions (S-T-S-T). During retrieval, participants were instructed to write down all the words they had just remembered within 5 minutes. For the restudy list, participants underwent four study sessions (S-S-S-S). Between each learning cycle, participants completed a 3-minute simple arithmetic task (dispersed attention task).
3. Testing phase:

Immediate Test: Participants were instructed to recall as many words as possible from the learned lists within 10 minutes after completing all learning tasks.

Delayed Test: Participants were informed to recall as many words as possible from the learned lists within 10 minutes 24 hours later.

Conditions

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Schizophrenic Patients

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

TREATMENT

Blinding Strategy

SINGLE

Participants

Study Groups

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tDCS group

In the tDCS group, the anode was placed over the left DLPFC (F3), and the cathode was placed over the contralateral supraorbital area (FP2). A direct current of 2mA was applied for 20 minutes during each stimulation session.

Group Type EXPERIMENTAL

tES-tDCS group

Intervention Type DEVICE

2mA/20mins/session

tACS group

In the tACS group, the anode was placed in the F3 region of the left dorsolateral prefrontal cortex (DLPFC), and the cathode was placed in the right supraorbital region (Fp2), and the current used was 2 mA AC at 40 Hz, with a stimulation time of 20 min.

Group Type EXPERIMENTAL

tES-tACS group

Intervention Type DEVICE

2mA/40Hz/20mins/session

sham group

In the sham group, the stimulation parameters, including the stimulation site and duration, were identical to those of the anodal group. However, during the 10-second ramp-up and ramp-down periods before and after stimulation, patients were unaware that the current was turned off.

Group Type SHAM_COMPARATOR

tES-sham group

Intervention Type DEVICE

0mA/20mins/session

Interventions

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tES-tDCS group

2mA/20mins/session

Intervention Type DEVICE

tES-tACS group

2mA/40Hz/20mins/session

Intervention Type DEVICE

tES-sham group

0mA/20mins/session

Intervention Type DEVICE

Eligibility Criteria

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Inclusion Criteria

1. Meeting the diagnostic criteria for schizophrenia according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5);
2. Aged 18 years or older, regardless of gender, with an educational level of elementary school or above;
3. All patients received stable-level antipsychotic medication treatment, were in a stable phase of disease treatment, able to understand the testing requirements, and cooperated to complete all research tasks;
4. No history of neurological disorders or other serious physical illnesses, and no history of intellectual disability;
5. No color blindness, color weakness, or other color vision impairments, with normal vision or corrected vision.

Exclusion Criteria

1. Clear cognitive impairment caused by somatic or cerebral organic lesions, such as cerebrovascular diseases, traumatic brain injury, etc;
2. Individuals with mental disorders caused by substance dependence or abuse, or the use of psychoactive substances;
3. History of brain injury or other central nervous system-related organic diseases;
4. Individuals at significant risk of suicide or harming others;
5. Participation in similar experiments in the past 30 days prior to baseline.
Minimum Eligible Age

18 Years

Maximum Eligible Age

60 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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Northeast Normal University

OTHER

Sponsor Role lead

Responsible Party

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Xiaofeng Ma

Professor

Responsibility Role PRINCIPAL_INVESTIGATOR

Principal Investigators

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Xiaofeng Ma, Professor

Role: PRINCIPAL_INVESTIGATOR

Northwest Normal University

Locations

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Northwest Normal University

Lanzhou, Gansu, China

Site Status

Countries

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China

References

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Hoy KE, Whitty D, Bailey N, Fitzgerald PB. Preliminary investigation of the effects of gamma-tACS on working memory in schizophrenia. J Neural Transm (Vienna). 2016 Oct;123(10):1205-12. doi: 10.1007/s00702-016-1554-1. Epub 2016 Apr 26.

Reference Type BACKGROUND
PMID: 27116682 (View on PubMed)

Sreeraj VS, Shivakumar V, Sowmya S, Bose A, Nawani H, Narayanaswamy JC, Venkatasubramanian G. Online Theta Frequency Transcranial Alternating Current Stimulation for Cognitive Remediation in Schizophrenia: A Case Report and Review of Literature. J ECT. 2019 Jun;35(2):139-143. doi: 10.1097/YCT.0000000000000523.

Reference Type BACKGROUND
PMID: 30024457 (View on PubMed)

Marko M, Cimrova B, Riecansky I. Neural theta oscillations support semantic memory retrieval. Sci Rep. 2019 Nov 27;9(1):17667. doi: 10.1038/s41598-019-53813-y.

Reference Type BACKGROUND
PMID: 31776375 (View on PubMed)

Javadi AH, Cheng P. Transcranial direct current stimulation (tDCS) enhances reconsolidation of long-term memory. Brain Stimul. 2013 Jul;6(4):668-74. doi: 10.1016/j.brs.2012.10.007. Epub 2012 Oct 31.

Reference Type BACKGROUND
PMID: 23137702 (View on PubMed)

Crossman M, Bartl G, Soerum R, Sandrini M. Effects of transcranial direct current stimulation over the posterior parietal cortex on episodic memory reconsolidation. Cortex. 2019 Dec;121:78-88. doi: 10.1016/j.cortex.2019.08.009. Epub 2019 Aug 28.

Reference Type BACKGROUND
PMID: 31550617 (View on PubMed)

McKay AP, McKenna PJ, Bentham P, Mortimer AM, Holbery A, Hodges JR. Semantic memory is impaired in schizophrenia. Biol Psychiatry. 1996 Jun 1;39(11):929-37. doi: 10.1016/0006-3223(95)00250-2.

Reference Type BACKGROUND
PMID: 9162204 (View on PubMed)

Provided Documents

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Document Type: Study Protocol

View Document

Document Type: Informed Consent Form

View Document

Other Identifiers

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No.2023025

Identifier Type: -

Identifier Source: org_study_id

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