An interventional study of Transcranial direct current stimulation (tDCS)-anodal group and Transcranial direct current stimulation (tDCS)-sham group in Schizophrenic Patients, sponsored by Northeast Normal University. Completed at 1 site in China. Open to participants aged 19 Years to 60 Years. Per ClinicalTrials.gov, last updated 2024-08-05.
Sponsored by Northeast Normal University · Not applicable, Interventional, and Treatment
The semantic processing deficit stands as a central feature of cognitive abnormalities in schizophrenia. Both transcranial direct current stimulation (tDCS) 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 tDCS and retrieval practice, following tDCS intervention targeting the left dorsolateral prefrontal cortex (L-DLPFC) in patients with schizophrenia, contributes to the preservation of semantic memory in these individuals.
Investigators recruited 52 patients diagnosed with schizophrenia from hospitals. After five consecutive days of tDCS intervention (2 mA × 20 mins, twice per day), Investigators administered a word list memorization task comparing retrieval practice and restudy strategies. Subsequently, Investigators observed their immediate and delayed memory performance through tests.
Treatment was administered by two examiners, and after a total of 10 sessions over 5 consecutive days, a final group of 52 patients participated in the learning and testing phase. Among them, 27 received anodal stimulation, while 25 received sham stimulation. Each participant of each stimulation type was involved in both learning conditions, meaning that all participants completed both retrieval and restudy learning and testing.
Stimulation phase:
In the anodal 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. Stimulation was conducted twice a day, at 9 a.m. and 2 p.m., for 5 consecutive days, totaling 10 sessions. 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.
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).
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.
3,471 studies on the registry are indexed under Schizophrenia; 472 are open to participants now.
This study's enrollment of 52 is below the median of 70 across 2,872 interventional studies indexed under Schizophrenia.
Browse Schizophrenia studies →Northeast Normal University is the lead sponsor of 13 studies on the registry; 5 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
In the anodal 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. Stimulation was conducted twice a day, at 9 a.m. and 2 p.m., for 5 consecutive days, totaling 10 sessions.
Device: Transcranial direct current stimulation (tDCS)-anodal 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.
Device: Transcranial direct current stimulation (tDCS)-sham group
2mA/20mins/session; 2sessions/day,5days
0mA/20mins/session; 2sessions/day,5days
The correct recall rate of word lists
The correct recall rate of word lists was calculated for each subject by the experimental assistant.
Time frame: 5mins to 24 hours
Adjusted Ratio of Clustering (ARC)
Free recall organization was measured by the Adjusted Ratio of Clustering (ARC) scores
Time frame: 5mins to 24 hours
Documents are hosted by the registry — open the source record to download them.
Plan to share: No
This study is completed, as verified in Jul 2024. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Northeast Normal University