Investigation of the Effects of Different Rehabilitation Approaches on Cognitive Functions, Dual Task Performance, and Manual Dexterity in Older Adults With Mild Cognitive Impairment
Investigation of the Effects of Different Rehabilitation Approaches on Cognitive Functions, Dual Task Performance, and Manual Dexterity in Older Adults With Mild Cognitive Impairment
This randomized controlled trial aims to comparatively examine whether cognitive training and hand exercise training provided to older adults with mild cognitive impairment (MCI) have an impact on their cognitive functions, hand skills, grip strength, activities of daily living, dual task performance, and interactions. Based on the study's objectives, the following hypotheses were formulated:
In this study, two different exercise interventions were applied to two experimental groups of individuals with mild cognitive impairment, while the control group did not receive any intervention. The first experimental group (Hand Exercise Group, HEG) and the second experimental group (Cognitive Training Group, CTG) underwent training administered by a physiotherapist three times per week for eight weeks.
To ensure assessor blinding, pre- and post-intervention assessments of the participants were conducted by an independent expert physiotherapist who was not involved in the study. The sociodemographic characteristics of the participants were collected using a data collection form. Cognitive functions were assessed with the Montreal Cognitive Assessment (MoCA); hand dominance was determined using the Edinburgh Handedness Inventory (EHI); hand dexterity was evaluated with the Nine-Hole Peg Test (NHPT); grip strength was measured using a hand dynamometer; motor-motor dual task performance (MMDTP) and motor-cognitive dual task performance (MCDTP) were assessed using a stopwatch; activities of daily living were evaluated with the Manual Ability Measurement-36, (MAM-36); and dual task interaction (DTI) was calculated using the following formula: DTI = (Single Task Performance - Dual Task Performance) / Single Task Performance × 100%.
The number of individuals aged 65 and older is increasing worldwide, leading to a rise in the elderly population. As this demographic grows, the prevalence and diversity of health problems associated with aging are also increasing. The most common health issues in aging individuals include cognitive impairments, dementia, cardiovascular diseases, arthritis, type 2 diabetes mellitus (DM), and cancer.
The primary underlying causes of the frequent health problems in elderly individuals stem from negative changes in their physical, psychosocial, and cognitive conditions. Notably, structural, physiological, and functional declines in cognitive domains significantly impact the lives of elderly individuals. Cognitive function encompasses a broad range of processes and structures, including emotion, memory, reasoning, language, sensory processing, comprehension, analysis, interpretation, learning, and motor skills. Aging leads to structural deterioration, functional decline, dysfunction, and eventual loss of these cognitive abilities, contributing to various levels of cognitive impairment in elderly individuals. Depending on the severity and the affected cognitive domains, aging individuals may develop different neurological disorders. The most prevalent neurological conditions associated with aging include Mild Cognitive Impairment (MCI), Alzheimer's disease (AD), Parkinson's disease (PD), multiple system atrophy, Lewy body dementia, amyotrophic lateral sclerosis (ALS), progressive supranuclear palsy, and frontotemporal dementia.
Mild Cognitive Impairment is characterized by memory loss or other cognitive deficits that are not severe enough to interfere with daily activities but represent a transitional phase between normal cognitive function and early dementia. Other cognitive deficits include attention, sensory processing, language, visual-spatial perception, praxis, and motor skills. In elderly individuals with MCI, the type and severity of cognitive impairment vary depending on the affected structures within the central nervous system. Although these cognitive impairments manifest at different levels, most elderly individuals with MCI can still perform many daily activities independently.
Motor functions are defined as learned skills aimed at achieving specific goals, with hand motor skills involving a series of complex movements. Hand movement is directly linked to the motor and somatosensory homunculus through short U-shaped fibers that pass beneath the central sulcus. The distribution of these short U-shaped fibers follows the topographic organization of the primary motor and somatosensory cortex. Compared to other body regions, there are greater interconnections between finger regions, and the cortical areas allocated for tactile and proprioceptive information from the fingers are more extensive than those for other body parts.
The neuronal connections that maintain and support the functionality of fine and gross motor skills of the hand interact with the cortical areas of the brain. Therefore, any degenerative changes in these neuronal connections and cortical areas may influence individuals' cognitive and motor functions. The cortical areas of the brain govern high-level cognitive functions such as attention, thought, memory, perception, reasoning, awareness, coordination, language, comprehension, and speech. The relationship between cognitive functions and hand skills is still a topic of debate.
The relationship between cognitive functions and hand skills is explained through two primary mechanisms. The first mechanism suggests that cognitive and motor processes within the central nervous system share common neural pathways and are influenced by the same neural processes. In other words, the neural circuitry responsible for hand motor functions may be associated with cognitive performance. The second mechanism explaining the relationship between cognitive functions and hand skills involves the aging-related decline in the frontal lobe, particularly in the frontoparietal and frontostriatal areas, which are responsible for higher-level cognitive functions. These areas play a crucial role in motor control of the upper extremities and are actively engaged in fine and gross motor activities. Therefore, improving gross and fine motor performance of the upper extremities may enhance cognitive functions in elderly individuals by stimulating the frontal lobe.
Based on this perspective, our study aims to explore the relationship between cognitive functions and hand skills by implementing hand exercises and cognitive training in different groups of elderly individuals with MCI. The literature includes few studies investigating the connection between cognitive function and hand function. Therefore, this study seeks to examine the effects of different training interventions on cognitive functions, hand skills, grip strength, daily living activities, dual-task performance, and interaction in elderly individuals with MCI.
As part of the study, elderly individuals with MCI will undergo cognitive training and hand exercise programs. The hand exercise programs will include functional task-oriented and resistance-based hand exercises. No prior study in the literature has comprehensively examined the impact of such interventions on cognitive functions, hand skills, daily living activities, dual-task performance, and interaction in elderly individuals with MCI.
The primary objective of this study is to comparatively evaluate the effects of cognitive training and hand exercise programs on cognitive functions, hand skills, grip strength, daily living activities, dual-task performance, and interaction in elderly individuals with MCI.
Inclusion Criteria:
Exclusion Criteria: