1- PhD Student of Psychology, Department of Psychology, University of Isfahan, Isfahan, Iran
2- Associate Professor of Neuroscience, Department of Psychology, University of Isfahan, Isfahan, Iran
3- Professor of Neurology, Department of Neurology, Isfahan University of Medical Sciences, Isfahan, Iran
4- Assistant Professor of Psychology, Department of Psychology, University of Guilan, Guilan, Iran
Abstract: (1980 Views)
Introduction
Multiple sclerosis (MS) is a progressive degenerative disorder, starting with different plaques in the brain or spinal cord (1). Recent reports emphasized that both grey matter and white matter are involved in MS, resulting in consistent disabilities, ranging from sensory-motor to cognitive symptoms (1). Cognitive dysfunctions in MS are prevalent in 43 to 70 percent of the patients, which are usually detected during the disease (2). Deficits in the speed of cognitive processing were reported as the most prominent cognitive dysfunction in MS (25); however, some other symptoms, including impairments in attention, executive functions, working memory, and long-term memory (1, 3, 4, 5), are all prevalent. Cognitive dysfunctions are basically diagnosed through a comprehensive neuropsychological assessment and then are targeted by cognitive rehabilitation techniques, by which both cognitive abilities and quality of life in the patients can be improved. It was reported that some patients with MS may be unemployed, and they may be confronted with difficulties in accomplishing daily familial jobs (7). Cognitive rehabilitation is purported to be effective in multiple sclerosis and was supported through recent studies. Prez et al. reported that a computerized cognitive rehabilitation program efficiently enhanced working memory, auditory memory, and executive functions (8). Mantinen et al. (10) and Stuifbergen (12) suggested that cognitive rehabilitation programs efficiently boosted the cognitive abilities of patients with multiple sclerosis in such a way that they were capable of accomplishing their routine cognitive functions in daily life (7). Filippi et al. (16) and Flavia et al. (17) stated that cognitive rehabilitation was effective on attention, memory, and executive functions in MS patients. In another line of studies, some authors tried to use brain imaging techniques in visualizing the effects of cognitive rehabilitation on MS; for example, Amato et al. (14) and Martinez Gonzalez et al. (31) have all shown that cognitive rehabilitation produced visible changes in MRI images of the brains of patients with multiple sclerosis.
The information processing model, which was proposed by Atkinson and Shiffrin (20) is based on encoding sensory stimuli as the sensory memory items and then decoding and processing information through short-term and long-term memory. Sensory memory is thought to keep the information for only some milliseconds, but short term or working memory is more capable of holding information from seconds to minutes, and long-term memory is the most competent storage of learning system, which is able to keep information for hours, days, months and years (21).
To the best of our knowledge, this is the first time that a cognitive program was constructed and tested in those patients in the country. Hence, the main aims of this study were firstly to recognize the range of cognitive symptoms in the patients and secondly to implement and assess the effects of a cognitive rehabilitation program based on an information processing model on the patients.
Methods
The design of this research was ‘sequential qualitative mixed method’ and implemented in three stages: a) comparing the patient and normal groups by statistical measures b) constructing the rehabilitation protocol according to the results of the first stage, by a qualitative method through content analysis and assessment, c) implementation of a clinical trial method in the intervention stage. The patients were recruited from Kashani hospital in Isfahan city in 2019, according to inclusion criteria. The sample consisted of 117 patients, which were selected accessibly. The control group was selected from a matched sample of friends and family members of the patients.
In the study's second phase, a rehabilitation program was designed and administered to the patient group. The rehabilitation protocol was adopted from Festa and Lazar (22), which included 12 weekly cognitive rehabilitation sessions with an emphasis on visual and verbal mnemonic strategies. The patient’s homework was designed in such a way that would be concordant with the real-world demands in the patient’s life.
In the third phase of the study, the sample size for each of the experimental and control groups and the degree of freedom for each of them were calculated, and with regard to the smallest sample size, the significance level of %99, the statistical power of 0.80, and effect size of 0.40, it was concluded that 25 subject for each group is sufficient. Then 50 patients with scores less than 1.5 standard deviations were selected and randomly assigned into experimental and control groups, each comprising 25 patients. Finally, the rehabilitation program was administered in 12 sessions weekly, each session four1 hour. After accomplishing the program, both groups were assessed and then reassessed after one month as the follow-up phase of the study.
Instruments:
1. Minimal Assessment of Cognitive Function in Multiple Sclerosis (MACFIMS), which was designed to assess cognitive functions in patients with multiple sclerosis in 2001 (25). The test was standardized for the Iranian population in 2012, and its reliability was reported as 0.7 to 0.8 using the test-retest method (26). Five subscales of MACFIMS were used in this study, included as:
2. Paced auditory serial addition test (PASAT), Symbol digit modalities test (SDMT), California verbal learning test second edition (CVLT-II), Brief visuospatial memory test-revised (BVMT-R), and Controlled oral word association (COWAT).
3. Beck depression inventory- short form (BDI-SF) was used to assess the depressive signs of patients. The test was compiled by Beck et al. in 2006, and the Cronbach alpha of its Persian form was reported as 0.84, with a sensitivity of 0.88 and specificity of 0.83 in the Iranian population (26).
Data Analysis
The data analysis of this study was accomplished through two phases, including a comparison between the experimental and control groups and the assessment of the effectiveness of cognitive rehabilitation on the patients, which were extensively explained through the paper.
Results
The present study found that there were significant differences between experimental and control groups in all of the scores, except for depression. Also there was a significant difference between two groups in auditory short term memory (P<0.01), auditory long term memory (P<0.01), visual short term memory (P<0.05), visual long term memory (P<0.01), attention (P<0.05), encoding (P<0.01), and semantic memory (P<0.01).
In the follow-up phase, there was a significant difference in auditory short term memory (P<0.01) and visual short term memory (P<0.05); however, there was not a significant difference in the auditory long term and visual long term memory.
Discussion
This study was comprised of two stages, including recognizing the patients' cognitive impairments, and constructing a cognitive rehabilitation program for the patients, and investigating its effectiveness. The findings of the first phase of the study showed that the patients were more impaired in attention, short-term memory, long-term visual and auditory memory, encoding, and semantic memory. These results were concordant with Altun et al. (1), and Ruano et al. (3) in attentional functions, and also similar to Audoin et al. (29) in the short-term memory of the patients with multiple sclerosis. The findings in long-term memory impairment in MS patients were also comparable to Altun et al. (1) and Thornton et al. (27). The range of cognitive dysfunctions following MS makes it necessary to design and develop new cognitive rehabilitation techniques to treat or at least relieve the cognitive symptoms (8).
The essential findings of this study suggested that firstly, both visual and auditory forms of memory, attention, encoding, and semantic memory in the patients with multiple sclerosis were enhanced by cognitive rehabilitation. Secondly, the effect of treatment on visual and auditory short-term memory was maintained in the follow-up.
This study confirmed that cognitive rehabilitation could be utilized for the treatment of cognitive impairments or deficits in patients with multiple sclerosis. Cognitive rehabilitation is an area that is worthy of being more and more scrutinized by researchers in the future.
Ethical Considerations
Compliance with ethical guidelines
The Ethics Committee of the University of Isfahan (IR.UI.REC.1400.004) has granted ethical approval for this research. A written informed consent was obtained from patients with multiple sclerosis and other participants. In addition, they were informed about the confidentiality of the information and their voluntariness in participation in the study.
Authors’ contributions
The first author was involved in the study design, data collection, analysis, and writing up. The second author was involved in writing and correcting the paper. The third and fourth authors were involved in the study design, clinical setting preparation, and data analysis. All of the authors read and approved the final manuscript.
Funding
No financial support has been received for this research.
Acknowledgments
We would like to thank the MS Center of Ayatollah Kashani Hospital, Isfahan, who collaborated with the researchers in this study.
Conflict of interest
The authors declare there was no conflict of interest.
Type of Study:
Research |
Received: 2021/05/7 | Accepted: 2021/07/16 | Published: 2021/11/16