**2. Cognitive function**

Cognitive function can be defined as mental process (cerebral activities) that lead to the gaining of knowledge which allows people to carry out their daily life activities [16]. Cognitive functions are mainly related to remembering, solving problems, making decision and understanding the language, problems or even issues like personal issues and health issues, focus, attention and others [2]. It also can be defined as memory which is tested by the stimuli either spoken or presented using another talking format or talking memory [17]. Moreover, it can be related to the large spectrum of cognitive capability among the middle- and old-aged group of people, which are having dementia as well as maintaining normal physiological function [18].
