Introduction
Hemispheric preference or lateralization refers to the preferred mode of cognitive processing that is linked with the predominant activity of one of the cerebral hemispheres, right or left. The right and left cerebral hemispheres are specialized for different functions. The initial idea of hemispheric preference was based upon the important work done by Dr. Roger Sperry in late 1960s, which he named “split-brain model.” He discovered that the human brain has two different ways of thinking. It is the propensity for one side of the brain to be used more than the other.[ 1 ] The exact timing of the evolution of brain lateralization is still a source of debate. According to Lenneberg, lateralization begins during language acquisition and is completed only after puberty.[ 2 , 3 ]
Functionally, the brain hemispheres are equally important, but they are not symmetric for specific cognitive function.[ 4 ] The left hemisphere is primarily responsible for logical and sequential data processing. On the other hand, the right hemisphere is in charge of processing information in a holistic and nonlinear manner.[ 5 , 6 ] The left hemisphere is thought to be more realistic, analytical, linear, logical, memory-based, and judgmental than the right hemisphere. While, the right hemisphere is recognized for having holistic functioning characteristics based on visual-spatial skills.[ 7 ] Kane and Kane had explained in detail comparisons of right and left hemispheric functions in their published work.[ 8 ]
Academic performance refers to the outcome of the activities of a learner that reflect the extent to which a person has accomplished the specific goals of the academic activities of the school, college, and university. The outcome of the performance of a learner in an academic environment is being assessed by various methods.[ 9 , 10 ] Even though there is no evidence for the best method, grading the students based on their performance in practical and theory exams is common method for the assessment of academic performance .
Various factors affect the academic performance of students, including study habits, attitude, motivation, race/ethnicity, and genetics.[ 11–13 ] Hemispheric preference is also believed to play a role in academic performance . Medical students need to develop a wide range of skills, some of which are domains of the left hemisphere and others of the right hemisphere. Logical thinking, fine motor skills, problem-solving, and organizing concepts are the domains of the left hemisphere. Analysis and memorization of visual information and spatial anatomical relationships, communication, and recognition of different shapes come under the right hemisphere domain.[ 14 ]
In recent times, the incorporation of skill-based learning into the curriculum has been strongly recommended for the production of efficient medical graduates. Being informed about the relationship between hemispheric brain preference and academic scores among medical students may help in implementing various teaching and learning methods.[ 15 , 16 ] It might also be useful for students and educators to apply effective teaching-learning methods to improve their performance. Hence, the rationale of this study is based on this concept of teaching and learning perspective. The objective of present study is to compare the hemispheric preference score with the academic performance of preclinical medical students.
Materials and Methods
The present study is a quantitative cross-sectional descriptive study in which the relationship between exposure and outcome is assessed at the same time in a specific population.[ 17 ] All the research procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional or regional) and with the Helsinki Declaration of 1975, amended in 2013.Ethical clearance was taken from the Institutional Review Committee (IRC) before proceeding for data collection (IRC/1500/019) on April 15, 2019.
Sample and sampling method
The study population consisted of students studying MBBS (100) and BDS (40) in their 1st year at BP Koirala Institute of Health Sciences (BPKIHS). A convenience method of sampling was used, which is a systematic method of collecting and recording each unit of the population.[ 18 ]
The Open Epi toolkit, a free and open-source software for epidemiologic statistics, was used to calculate the minimum sample size.[ 19 ] The mean and standard deviation (SD) were derived from a study conducted among higher secondary level science students in India.[ 20 ] To calculate the sample size, the assumptions made were-confidence interval (2 sided): 95%; power: 80%; mean score of right hemispheric score: 22.64; SD of right hemispheric score = 4.83; mean score of right hemispheric score: 18.21; SD of right hemispheric score = 4.21; nonresponse = 10%.
Despite the fact that the minimum sample size was 40, the current study included all 1st -year medical students studying MBBS and BDS. Inclusion criteria were 1st -year medical students (MBBS and BDS) who completed the questionnaire. Exclusion criteria were students who did not complete the questionnaire or were absent.
Measurement instruments
The data collection tool used was the Style of Learning and Thinking (SOLAT) questionnaire for determining the hemispheric preference for learning and thinking. The SOLAT tool was developed and standardized by Dr. Venkataraman (1994), an Indian expert.[ 21 , 22 ] This is a more advanced version of the Torrance SOLAT test[ 5 ] that consists of 50 items. It is simple, easy to understand, and best suited for learning environments.[ 22 ] Each item consists of two statements (a) and (b). The statement “a” represents the right hemispheric preference (R score), statement “b” represents the left hemispheric preference (L score), and checking both statements represents the integrated or whole hemisphere (W score).[ 6 , 22 ] The authors of the SOLAT tool used the test-retest method to assess the tool’s reliability. The reliability coefficient of correlation for the right hemisphere function was 0.89, the coefficient of correlation for the left hemisphere function was 0.65, and the coefficient of correlation for the integrated function was 0.71. These coefficients indicate that the SOLAT tool has a high level of reliability.[ 6 , 22 , 23 ] Due to copyright issue, the SOLAT tool and manual were purchased from its publisher, and permission was obtained via E-mail for use in this research project.
A semi structured self-designed proforma was also used for the collection of demographic and other characteristics of students that might affect students’ academic performance . For the sake of feasibility, the study was conducted in the lecture theater and practical room.
Data collection
After taking ethical approval from the IRC of the university, researchers collected the list of students studying MBBS and BDS from the class representatives of the respective courses. Students were informed about the objective of the study in the lecture theater and practical classroom followed by completing the informed consent form for participation in the research. After providing instruction and answering the doubts, printed copies of the SOLAT questionnaire were distributed to all the students who consented to participate in the research. All completed questionnaires were collected from the students. Other information such as gender, age, nationality, method of study, approximate study hours per day (excluding classroom study), and study habits were also recorded.
Data management and statistical analysis
Data were entered into Microsoft Excel (Redmond, WA: Microsoft Corporation, 2007) and then analyzed by the Statistical Package for Social Sciences (SPSS) version 20 (IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY, USA: IBM Corp.).
For the descriptive statistics, the results were presented as percentages, mean scores, and SDs. To generate the inferential statistics, the students were divided into three equal groups based on their academic performances in the theory and practical exams. Students who scored the highest were labeled as high achievers, those who scored average marks were labeled average achievers, and those who scored the lowest marks were labeled low achievers.
Quantitative variables were checked for normality using the Kolmogorov − Smirnov and Shapiro–Wilk tests before conducting inferential statistical tests. The score (percentage) in the theory exam and total right hemispheric scores were normally distributed (P > 0.05); all other variables were not. Student’s t -test (or Mann–Whitney U -test for nonparametric data) was used to compare hemispheric preference scores between two groups of students on the basis of academic performance , i.e., high achievers and low achievers. The Pearson correlation coefficient test (or Spearman correlation coefficient test for nonparametric data) was used to calculate the correlation coefficient between the hemispheric preference score and exam score (percent). P < 0.05 was considered statistically significant.
Results
The current study included 137 students from the 1st year of MBBS (n = 95) and BDS (n = 42). The subjects’ ages ranged from 18 to 25 years. The male-female ratio was 1.36. The Nepalese to Indian nationality ratio was 2.51. The majority of the subjects (n = 129) were right-handed. The mean study hours per day were 3.53. Other variables related to study habits are depicted in Table 1 .
Table 1: Sample distribution according to various qualitative variables
The mean values of the total right score, total left score, and total whole score were 26.51 (SD = 5.95), 14.5 (SD = 4.61), and 6.76 (SD = 5.64), respectively. The mean values of academic score obtained on the practical and theory exam were 57.37 (SD = 14.99) and 56.42 (SD = 11.38), respectively [Table 2 ].
Table 2: Descriptive statistics of mean hemispheric preference scores and academic performance
Table 3 and Figure 1 show the comparison of the right, left, and whole hemispheric scores between the low achievers and high achievers in theory exam. Students with a higher R score (27.53 ± 6.91) performed poorly compared to the students with lower R scores (26.00 ± 4.53), but the students with higher L scores (14.61 ± 4.73) were high achievers and those with lower L scores (14.58 ± 4.30) were low achievers. Similarly, the case of integrated brain score (W score) being higher in high achievers was observed. When the right and left hemispheric preference scores were compared between low and high achievers, none showed the statistical significant difference (P > 0.05).
Table 3: Comparison of hemispheric scores with academic achievement in theory exam
Figure 1: Box plot displaying the comparison of academic achievement with right and left hemispheric preference scores
Table 4 and Figure 1 show a comparison of hemispheric scores with academic achievement in the practical exams. It revealed that the low achievers had a higher R score (27.09 ± 7.45), lower L score (14.40 ± 4.54), and lower W score (6.02 ± 6.27) as compared to the high achievers. When the right and left hemispheric scores of students were compared between the high and low achievers in the practical exams, none showed statistical significant difference (P > 0.05).
Table 4: Comparison of hemispheric preference scores with academic achievement in practical exam using Mann–Whitney U -test
Table 5 showed the comparison of academic performance between students’ nationalities, gender, and course of study. The score on the practical exam was significantly higher among the Nepalese students than the Indian students. The gender-wise comparison showed that males achieved a significantly higher score than females (P < 0.05). Similarly, exam scores also differed significantly between students studying MBBS and BDS (P < 0.001).
Table 5: Comparison of academic score between nationality, gender and course of study
Table 6 displayed the bivariate correlation between hemispheric scores and academic performance in theory and practical exams. Theory exam scores and practical exam scores were positively correlated (r = 0.94) and significant at the 0.01 level (P < 0.001). The total R score was negatively correlated with the academic score for theory (r = −0.108) and practical exams (r = −0.122). Unlike the R score, the total L score was positively correlated with the academic score for theory (r = 0.041) and practical exams (r = 0.037). There were no statistically significant correlations between hemispheric scores and academic performance .
Table 6: Bivariate correlation between quantitative variables (academic performance and hemispheric scores) using spearman and pearson correlation coefficient
Discussion
The purpose of the undergraduate medical education is to help students acquire the knowledge, skills, and attitudes required for the profession. The curriculum of each medical university should define these domains of learning outcomes. The curriculum of MBBS and BDS course at BPKIHS is divided into phase I (preclinical) and phase II (clinical). In both phases, students are assessed by theory and practical exams. During the preclinical years of medical education, students have to learn and face exams in many subjects, i.e., anatomy, physiology, biochemistry, pharmacology, microbiology, and pathology. Preclinical students are assessed by asking short answer questions, multiple-choice questions, and problem-based questions for theory exams. Similarly, objective structured practical exams (OSPE) and oral examinations or viva voce are used for practical exams.[ 24 ]
Individual differences of students in their learning patterns, academic ability, achievement level, and hemispheric preferences are key issues for an instructor to identify the specific instructional or teaching method that will be effective for the specific type of learners.[ 12 , 25 , 26 ] For this reason, it is critical to identify students’ hemispheric preference which refers to preference of either of the cerebral hemispheres (right or left) for processing information and retaining it.[ 8 ] The current study included 137 students from the first year of MBBS (n = 95) and BDS (n = 42) courses. The mean age of the students was 20.16 ± 1.38 years.
According to the present study, students who scored higher on the theory and practical exams had higher L scores than the students who scored lower; but the difference was not statistically significant [Table 3 ]. There are very few studies comparing academic performance with hemispheric preference score. A study performed by Koju et al . among 400 medical students showed that left hemispheric preference was found in those students who achieved higher scores in the exam compared to those who showed right hemispheric preference . Despite this difference, it was not statistically significant.[ 14 ] The results of the current study also support the assumption that integrated brain function is necessary for solving the task or questions given during assessment. Though the difference was not statistically significant, the students who achieved higher scores on theory and practical exams had higher W scores than those who achieved lower scores. A few other studies also concluded that there is no statistically significant association between academic performance and hemispheric preference .[ 27 , 28 ]
To do well on the exam, a student needs a good balance of right and left hemispheric function. Oflaz concluded that right-brained and left-brained students performed differently on English vocabulary tests and English reading tests. Right-brained students were better performers when the task was to understand instructions and visual signs, while left-brained students were better in tasks related to understanding by making logical reasoning.[ 29 ] Good verbal memory, knowledge expression, language processing and comprehension, rational thinking, and logical word expression are needed for answering most of the questions. The left hemisphere is believed to be dominant for these functions.[ 20–22 ] Drawing the diagrams and identifying the specimen/objects during a practical exam (for example OSPE) require spatial orientation, tactile awareness, retention of a visual pattern, and drawing the visual pattern by recalling its shape and geometry is important to answer the questions assessing psychomotor domain of learning, which is controlled preferably by the right hemisphere.[ 3 , 23 ]
Teachers’ knowledge of the students’ hemisphere scores could assist them in creating the activities or assignments that meet students’ needs, in improving the efficiency of their teaching approach, in designing the curriculum, and in recommending the learning tactics to the students.[ 17 ]
This is the only cross-sectional study that looked at students’ brain dominance score between high and low academic achievers. It is lacking in the incorporation of the specific task to the students with different hemispheric preferences to observe the effect of the same in problem solving. It is recommended to conduct the study incorporating the specific tasks.
Conclusion
Preclinical medical student studying MBBS and BDS had differences in hemispheric scores (right, left and whole brain) and study habits. Individual method of study was the major method of study. The left hemispheric (L) score and whole brain (W) scores were found to be higher in high achievers. While, right hemispheric score (R score) was lower among high achievers. None of the differences was statistically significant.
Ethical approval and informed consent
The Institutional Review Committee (IRC) of BPKIHS approved the study (Reference: IRC/1500/019). The SOLAT questionnaire was provided to the students after obtaining informed consent. Emphasis was given to the issue of confidentiality of the information about participants’ characteristics.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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