Aging is a natural, universal and inevitable process seen in all living things. With aging, structural and functional irreversible degenerative changes occur in molecules, cells, tissues, organs and systems in living organisms. These changes, which extend from cells to systems in aging, may cause limitations in the functions necessary for elderly individuals to maintain their daily life activities such as walking, balance, coordination, visual and auditory skills, cognitive skills and dexterity. WHO defines old age as the period between 65-74 years of age as young old age, 75-84 years of age as middle-aged, and 85 years and older as old age (old age). Manual dexterity is the ability to move an object in a desired manner and is necessary to carry out activities of daily living. Decreases in dexterity may occur with aging, which leads to limitation of activities of daily living. Impaired dexterity leads to a progressive deterioration in the performance of activities of daily living that require the use of the hands. Therefore, the ability of older adults to live comfortably and independently is negatively affected. Numerous factors such as loss of grip strength, sensory disabilities, decreased vision, neuro-muscular problems and cognitive decline can lead to impaired dexterity in older adults. It has been shown that there is a further decline in dexterity with increasing age. One of the reasons affecting manual dexterity in the elderly is cognitive functions. Cognitive functions are a set of functions that enable the perception and understanding of all kinds of inputs received from the sensory organs. These functions include alertness, attention, memory, executive functions, planning, abstraction, language skills, time-space orientation and arithmetic. As with all physiological structures, cognitive functions are also impaired with aging. As age advances, impairments in cognitive functions become more noticeable. The term Dual Task (DT) refers to the ability to perform a cognitive and a motor task simultaneously. The addition of a concurrent cognitive task while performing a motor task often leads to impairment in motor task performance, referred to as the dual task effect (DTE) or dual task cost (DTC). Motor control and executive function are key elements of IG ability, and both are negatively affected by the aging process. Many of the activities of daily living of older adults require dual tasks, such as reading while walking or talking while using cutlery. Therefore, the ability to perform IG is essential for older adults to maintain functional independence. In previous studies, it was observed that when a second cognitive task was given while performing a motor task, motor task and cognitive task decreased; however, the effects of different cognitive tasks on manual dexterity motor task and the difference between young elderly (65-74) and middle-aged (75-84) were not examined. The aim of this study is to examine the effects of cognitive tasks that affect different cognitive functions such as attention, memory and executive functions on the dexterous motor task and to evaluate and compare the differences in two different elderly groups (young and middle-aged). Our study is of great importance in terms of evaluating which cognitive functions are affected during a dual task in elderly individuals and how much dexterity is affected by these functions. Since our study is to obtain data from a certain group in a certain period of time, the type of the research was determined as a cross-sectional study. There are dependent and independent variables in the study. The study aims to examine the effect of different cognitive dual tasks added to a motor task requiring manual dexterity on manual dexterity in geriatric individuals in two different age groups. In this context, the independent variables in the study are the type of cognitive task and age. In total, 4 different cognitive tasks were determined. The dependent variable is dexterity performance. The extent to which dexterity will be affected by 4 different cognitive task types and age will be examined.

Inclusion Criteria:

• The participant was determined to be between the ages of 65-84, to be able to cooperate, and to have no obstacle to vision and hearing problems.

Exclusion Criteria:

• The participant had any neurological, rheumatologic and noromuscular disease that would affect the dexterity of the participant, the Mini mental test was below 24, the participant had a hand use problem after any hand injury.

"This study does not plan to share individual participant data due to ethical and privacy considerations."