The Effectiveness of Cognitive Rehabilitation Based on Computer Tasks on Improving the Cognitive Deficits of Patients with Schizophrenia: A Randomized Controlled Clinical Trial

Schizophrenia is a serious mental health condition affecting approximately one percent of the world’s population (1). Schizophrenia, as defined by the American Psychiatric Association, is a mental health condition characterized by a range of symptoms, including delusions, hallucinations, disorganized speech, and negative symptoms, such as diminished emotional expression or lack of motivation and volition. By diagnostic criteria, these symptoms must persist for at least six months (2, 3). The onset of schizophrenia symptoms typically occurs between late adolescence and the middle of the third decade of life. In men, symptoms appear before the age of 19 years in approximately 40% of cases, while in women, they appear before the age of 19 years in approximately 23% of cases (4). It appears to have a higher incidence in men than in women, as indicated by the negative symptoms and the duration of involvement. Moreover, based on various diagnostic criteria and definitions of the disorder, men tend to experience more severe symptoms of schizophrenia than women (5, 6).

Susceptibility to schizophrenia is significantly shaped by hereditary factors, as demonstrated in various studies. Specifically, the prevalence of schizophrenia among third-degree relatives is approximately 2%, while it ranges from 2% to 6% among second-degree relatives. The incidence of schizophrenia among first-degree relatives is estimated to be between 6% and 17%. It is worth mentioning that the prevalence of schizophrenia in non-identical twins is approximately 17%, and identical twins who share the same genetic makeup have a prevalence of roughly 50% (7, 8). Environmental factors such as infection, stress during pregnancy or childhood, and socioeconomic environments are significant contributors to the development of schizophrenia symptoms. Other causes of the disease include social isolation, migration resulting from social hardship, racial discrimination, family disruption, unemployment, and inadequate housing conditions (9-11).

Positive symptoms of the disease include symptoms that are ordinarily absent in individuals but present in schizophrenia patients, such as delusions (including persecutory, grandiosity, erotomania, and etc.), hallucinations (auditory, visual and etc.), and disorganized speech (incoherency, blocking of thought, echolalia and etc.). Additionally, patients may exhibit disorganized behaviors (disorganized dress and appearance, repetitive and stereotyped behavior, and etc.) (12-14). In most cases, there is an observable pattern of emotional distress, such as unresponsiveness to stimuli (13). Impaired social cognition is directly related to schizophrenia and symptoms of paranoia, and social isolation are common (15). Furthermore, issues regarding working and long-term memory, attention, executive function, and processing speed can occasionally arise. On rare occasions, individuals may exhibit signs of juvenile insanity, such as being largely silent, engaging in unusual postures, or displaying inappropriate expressions of anxiety (16-18).

The present study examined the efficacy of cognitive rehabilitation employing computer-based tasks in ameliorating cognitive deficits in patients with schizophrenia who were admitted to the inpatient adult wards of Dr. Hejazi and Ibn Sina hospitals in Mashhad at first half of 2021.

Cognition encompasses the mental activities necessary to acquire, process, and organize information. These functions also enable individuals to gather and utilize relevant information to engage in meaningful interactions with their environment and with others. Cognitive deficits are a defining characteristic of schizophrenia and are often present at the onset of symptoms and throughout the duration of the illness. In most cases, these deficits remain stable for the remainder of a patient’s life, with a direct correlation between the severity of cognitive impairment and responsiveness to treatment (19, 20). Cognitive deficits in schizophrenia are distinct from those in other psychological and neurological disorders, affecting memory, attention, reasoning, problem-solving, and social cognition. Several studies have identified seven cognitive factors that are disturbed in patients with schizophrenia: Processing speed, attention and vigilance, working memory, learning and visual memory, reasoning, problem-solving, and perception (21-23). Cognitive rehabilitation is a therapeutic approach that aims to enhance a person’s cognitive abilities, including memory, attention, understanding, learning, planning, and judgment, through structured activities and interventions such as cognitive exercises, computer-aided training, compensatory techniques, assistive devices, communication skills training, aerobics, music, and art (24-26).

This study was a randomized clinical trial involving 30 patients that compared the effectiveness of computer-based cognitive rehabilitation in improving cognitive deficits in patients with schizophrenia. The PANSS test, Wisconsin Card Sorting Test, digit span test, Stroop test, and Ray memory questionnaires were employed. In Wisconsin Card Sorting Test, a significant reduction was observed in perseveration errors, indicating improved in executive function. In the digit span test, a significant difference was observed in the number of forward digits, indicating improved concentration in patients with the digit sequence initially ascending and then descending. However, no significant changes were observed in the other areas. In the Stroop test, the incongruent corrects, congruent errors, incongruent errors, and incongruent reaction time showed a downward and significant change, leading to increased processing speed in patients with schizophrenia, although other areas were significant in some weeks, but the trend of changes was not significant, possibly because of the slowness of improvement. In the Ray memory test, the immediate auditory memory item showed a significant upward trend. The immediate and delayed visual memory items exhibited a significant audio trend in some weeks, but the overall trend was not significant, likely due to the slowness of the changes.

In the PANSS test, all items related to positive, negative, and general symptoms were not significant in the intervention group and the difference between the two groups was not significant, making it clear whether the improvement was not due to the intervention and probably because of drug treatment.

In the Treichler et al.’s study, 46 patients were divided into two groups for either traditional cognitive rehabilitation or auditory-targeted cognitive training (TCT). While cognitive performance improved in terms of memory and executive function, mental cognitive dimensions remained unchanged in the TCT group. Additionally, no significant relationship was found between mental cognitive dimensions and the symptoms of depression and hallucinations. The study results indicated that the lack of improvement in subjective symptoms may be related to depression, lack of motivation, and patient satisfaction (27). In our study, we observed significant changes in memory domains, but no significant changes in response speed and selective attention, which differs from the results of another study. Our study also examined the effects of lack of motivation, satisfaction, and depression symptoms, which are crucial in test-taking. Both studies suggested that computer-based cognitive exercises improve memory and attention.

In 2018, Pena et al. (28) randomly assigned 110 patients with schizophrenia to a 4-month computer-assisted cognitive training program. This study found that processing speed and verbal memory improved but other social cognitive domains and negative symptoms remained unchanged. This study, in line with our findings, showed significant improvements in cognitive processing speed, working memory, and verbal skills. However, our study also demonstrated significant changes in positive and negative symptoms of schizophrenia. Additionally, our study had a larger sample size and utilized the UCSD Performance-Based Skills Assessment (UPSA) tool to evaluate cognitive domains. The results of both studies suggest that cognitive rehabilitation treatment for at least 3 - 4 months can be effective in improving attention, memory, and processing speed. Our study, in agreement with many previous studies, showed that cognitive rehabilitation had a significant impact on memory, processing speed, executive function, and visual memory (29, 30).

In another study cognitive areas such as attention/vigilance, verbal working memory, and verbal learning were found to differ significantly from those of the control group, while there was no change in non-verbal working memory and learning. Additionally, there was no change in processing speed or functional outcomes. This suggests that cognitive rehabilitation is suitable for patients with schizophrenia but does not improve their performance. Like the present study, a significant difference was observed in attention and working memory. However, unlike in the present study, there was no significant change in cognitive processing speed. Moreover, there was no significant change in executive performance. It seems that cognitive rehabilitation in patients with schizophrenia leads to improvement in many cognitive domains but does not affect executive function. This finding suggests the need for longer interventions to investigate this further (31).

In Jamilian et al.’s study, participants received cognitive rehabilitation sessions three times a week for 40 min each session. The researchers assessed memory, number pronunciation, visual memory, and word pronunciation, before and after the intervention. The results showed that the experimental group had improved scores in listening memory, visual memory, and word pronunciation compared with the control group. Similar to the present study, this study found significant improvements in auditory memory and number pronunciation through cognitive rehabilitation but did not investigate other cognitive domains, such as executive function or attention (32).