Analysis and optimization of a combined foot dominance scale for easier and effective assessment of lateralization in patients with schizophrenia

Bulgarian Medical Journal, 2023, 17(3), 51-56.

K. Akabalieva

Department of Psychiatry and Medical Psychology, Faculty of Medicine, Medical University – Sofia

Abstract. Backgraund: The aim of the study was to investigate the reliability (internal consistency) of the Combined Foot Dominance Scale and its optimization in order to provide more effective tool for assessing lateralization in patients with schizophrenia. Subjects and Methods: 98 patients with schizophrenia were assessed by the Combined Foot Dominance Scale, which consists of the Chapman & Chapman Foot Dominance Scale and 4 additional questions for a more complex assessment of foot dominance. Spearman’s rank coefficient and reliability statistics (item-scale statistics, item summary statistics, Cronbach’s alpha) were used. Results: The scale shows good internal consistency with positive mean inter-item correlations. Some items in the Combined Foot Dominance Scale show higher mean values than other, suggesting a greater contribution of these items to the overall scale mean. Conclusions: Unlike hand dominance, foot dominance reflects lateralization more objectively and without the influence of cultural differences. By excluding some of the items that make little contribution to the scale’s overall mean, the scale can be a more compact and easy-to-apply instrument for assessing lateralization.

Key words: schizophrenia, laterality assessment, Combined Foot Dominance Scale, internal consistency

Address for correspondence: Dr Katerina Akabalieva, e-mail: katerina_akabalieva@yahoo.com