Hypertension Linked to Impaired Cognition & Gait in Older Adults (2024 Study)

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Hypertension in older adults leads to poorer cognitive and walking performance due to the need for more brain resources to manage dual tasks.

Highlights:

  • Older adults with hypertension show higher brain activation in motor and sensory areas when performing dual cognitive-walking tasks compared to healthy peers.
  • Hypertensive individuals have worse cognitive performance on single cognitive tasks than healthy older adults.
  • Hypertension causes impaired executive function and walking ability, leading to inefficient brain resource allocation during complex tasks.
  • Higher cortical activation in hypertensive patients suggests they require more effort to perform tasks that healthy individuals find easier.
  • Assessing cognitive and gait functions in hypertensive elderly through dual-tasking can help detect early signs of cognitive decline.

Source: Brain & Behavior (2024)

Key Findings: Hypertension in Older Adults vs. Cognition & Walking Performance (2024)

1. Cortical Activation Differences

A. In Dual-Task (DT) vs. Single-Task (SW)

Hypertensive Older Adults (HT)

When performing dual tasks (DT), hypertensive older adults showed significantly higher brain activation in the left somatosensory cortex (L-S1) and both sides of the supplementary motor area (SMA) compared to healthy older adults (HA).

This means they needed more brain power to handle doing two things at once.

Within the HT group, multiple brain areas, including the left and right anterior prefrontal cortex (L-APFC, R-APFC), right dorsolateral prefrontal cortex (R-DLPFC), left and right primary motor cortex (L-M1, R-M1), and the left and right SMA, were more active during dual tasks compared to single walking tasks (SW).

Healthy Older Adults (HA)

Healthy older adults showed no significant differences in brain activation between DT and SW, suggesting they used their brain resources more efficiently.

B. Single Cognitive Task (SC) Performance

Hypertensive Older Adults (HT)

Hypertensive adults did not show significant differences in brain activation during single cognitive tasks (SC) compared to dual tasks (DT).

However, they performed poorly on SCs, indicating a decline in working memory function.

2. Cognitive & Gait Performance

Cognitive Performance

Hypertensive Older Adults (HT)

HT individuals performed significantly worse on the 2-back task (a memory test) in terms of accuracy, missing presses, and reaction time compared to HA.

There were no significant differences in DT performance between HT and HA.

Gait Parameters

Hypertensive Older Adults (HT)

HT showed lower step speeds, step lengths, and stride lengths during DT compared to SW. This means their walking performance declined when they had to do a cognitive task at the same time.

There were no significant differences in step frequency during DT and SW.

Healthy Older Adults (HA)

HA also showed reduced step speeds, step lengths, and step frequencies during DT compared to SW, but their stride length remained consistent.

3. Correlation Between Cortical Activation & Gait Parameters

Healthy Older Adults (HA)

During DT, there was a negative correlation between left SMA activation and step frequency, right SMA activation and step length, and right S1 activation and step length.

This suggests that more brain activation in these areas was associated with reduced walking performance.

Hypertensive Older Adults (HT)

During SW, there was a negative correlation between right DLPFC activation and step frequency.

During DT, negative correlations were found between various brain regions (L-APFC, R-APFC, L-SMA, L-S1, L-M1, R-SMA, R-M1) and gait parameters (step frequency, step speed).

This indicates that increased brain activation was associated with poorer walking performance.

4. Recap of Findings

Hypertension & Cognitive Decline: Hypertensive older adults exhibit higher brain activation to compensate for both cognitive and motor tasks, suggesting they need to use more brain resources inefficiently. Their cognitive performance, especially working memory, is significantly impaired during single cognitive tasks.

Impact on Gait: Both hypertensive and healthy older adults show reduced walking performance under dual-task conditions. However, hypertensive individuals need more brain resources to manage these tasks, indicating a higher cognitive load and greater difficulty in performing dual tasks.

Clinical Implications: Early detection of cognitive and gait impairments in hypertensive older adults through dual-task assessments can help develop targeted interventions. Understanding the relationship between brain activation and walking performance can aid in designing rehabilitation programs to improve both cognitive and motor functions in hypertensive patients.

How Hypertension May Impact Cognition & Gait in Older Adults (Possible Mechanisms)

1. Vascular Changes & Brain Function

Atherosclerosis & Arterial Stiffness: Long-term hypertension leads to atherosclerosis and stiffening of the arteries. This causes reduced elasticity of blood vessels, which can impair cerebral blood flow and oxygen delivery to the brain, negatively impacting cognitive functions and gait control.

Blood Pressure Variability: Hypertension often results in greater fluctuations in blood pressure, which can lead to periods of inadequate cerebral perfusion. This variability can cause chronic damage to the brain’s vascular structure, contributing to cognitive decline and motor function impairment.

2. Neurovascular Coupling Impairment

Dysregulated Cerebral Blood Flow: In hypertensive patients, the ability to regulate cerebral blood flow in response to neural activity (neurovascular coupling) is impaired. This dysregulation means that brain regions do not receive adequate blood flow during cognitive or physical tasks, leading to decreased performance and efficiency.

3. Structural Brain Changes

White Matter Lesions: Hypertension is associated with an increased prevalence of white matter lesions, which are areas of damaged brain tissue. These lesions disrupt communication between different parts of the brain, affecting both cognitive processes and motor control necessary for walking.

Brain Atrophy: Chronic high blood pressure can accelerate brain atrophy, particularly in regions associated with executive function and motor control, such as the prefrontal cortex and motor cortex. This atrophy contributes to declines in cognitive abilities and gait stability.

4. Cognitive Load & Brain Resource Allocation

Increased Cognitive Load: Hypertensive individuals often exhibit higher cortical activation during tasks, indicating that they need to use more brain resources to achieve the same level of performance as healthy individuals. This increased cognitive load can impair both cognitive functions and gait when multitasking.

Neural Inefficiency: Higher brain activation in hypertensive patients is often associated with poorer task performance, suggesting that their brains are less efficient in allocating resources. This neural inefficiency can lead to difficulties in managing dual tasks that require both cognitive and motor skills.

5. Neuroinflammation & Oxidative Stress

Chronic Inflammation: Hypertension is linked to chronic low-grade inflammation, which can affect brain health. Neuroinflammation contributes to the progression of neurodegenerative diseases and cognitive decline, impacting executive function and gait.

See also  Effects of REM Sleep Deprivation on Brain Connectivity (2024 Study)

Oxidative Stress: Elevated blood pressure increases oxidative stress, leading to damage of brain cells and vascular structures. Oxidative stress disrupts normal neuronal function and impairs the brain’s ability to coordinate complex tasks such as walking while thinking.

6. Antihypertensive Medications

The type, dose, and duration of antihypertensive medication use can influence cognitive and motor functions.

While some medications may protect cognitive function by stabilizing blood pressure, others might have side effects that affect alertness and motor control.

Possible Ways to Counteract the Effects of Hypertension and Normalize Brain Activity in Older Adults (Ideas)

1. Medication Management

Antihypertensive Therapy: Regular monitoring and adjusting antihypertensive medication can help maintain stable blood pressure levels, reducing the risk of cerebral blood flow variability and subsequent cognitive impairment.

Managing Polypharmacy: Minimizing the use of medications that could impair cognitive function and ensuring that the antihypertensive regimen is tailored to the individual’s overall health and cognitive needs.

2. Physical Exercise

Aerobics (Cardio): Regular aerobic exercise, such as walking, swimming, or cycling, can improve cardiovascular health, enhance cerebral blood flow, and reduce hypertension.

Strength Training: Incorporating strength training exercises can improve muscle strength and endurance, which can help maintain better gait and balance, reducing the risk of falls and improving overall mobility.

3. Diet & Nutrition

Adopting a Heart-Healthy Diet: Consuming a diet rich in fruits, vegetables, whole grains, lean proteins, and healthy fats can help manage blood pressure and provide essential nutrients for brain health.

Omega-3 Fatty Acids: Including omega-3 fatty acids in the diet, either through fish or supplements, can reduce inflammation and oxidative stress, promoting better brain health and cognitive function.

4. Stress Management

Mindfulness & Meditation: Practicing mindfulness, meditation, and relaxation techniques can help reduce stress levels, which in turn can help lower blood pressure and improve cognitive function.

Biofeedback & Relaxation Training: Using biofeedback techniques to learn how to control physiological functions, such as heart rate and muscle tension, can help manage stress and improve blood pressure control.

5. Sleep Hygiene

Improving Sleep Quality: Ensuring adequate and quality sleep is essential for cognitive health. Practices such as maintaining a regular sleep schedule, creating a restful sleep environment, and avoiding stimulants before bedtime can improve sleep quality and cognitive functions.

Addressing Sleep Disorders: Treating sleep disorders such as sleep apnea or insomnia can significantly impact blood pressure control and cognitive health. Consultation with a sleep specialist may be necessary.

6. Regular Monitoring & Health Check-Ups

Routine Medical Examinations: Regular check-ups with healthcare providers can help monitor blood pressure, assess cognitive functions, and adjust treatment plans as needed. Early detection and intervention are key to preventing further cognitive decline.

Cognitive Assessments: Periodic cognitive assessments can help track changes in cognitive function over time and allow for timely interventions if a decline is detected.

7. Social Engagement

Maintaining Social Connections: Engaging in social activities and maintaining strong social connections can provide mental stimulation and emotional support, which are beneficial for cognitive health.

Group Activities: Participating in group exercise classes or cognitive training sessions can provide both physical and mental benefits, as well as promote social interaction.

Study Overview: Cerebral Cortex Activation vs. Gait & Cognition in Hypertensive Adults (2024)

The aim of this study was to explore the differences in cerebral cortex activation, gait parameters, and working memory performance between healthy older adults (HA) and older hypertensive (HT) patients when performing cognitive and walking tasks.

Sample

A total of 36 participants were included in the study:

  • Healthy Older Adults (HA): 12 participants
  • Older Hypertensive Patients (HT): 24 participants

Methods

Experimental Design

Participants were asked to perform three types of tasks:

  1. Single Cognitive Task (SC): Performing a 2-back memory task while standing.
  2. Single Walking Task (SW): Walking freely at usual speed in a 40m corridor.
  3. Dual-Task (DT): Performing the 2-back task while walking.

Data Collection

  • Brain Activity: Measured using functional near-infrared spectroscopy (fNIRS) to record cortical hemodynamic reactions.
  • Gait Parameters: Recorded using Intelligent Device for Energy Expenditure and Activity (IDEEA®) to capture step length, step speed, step frequency, and stride length.

Analysis

  • Cognitive performance was evaluated using the 2-back task accuracy, missing press rate, and reaction time.
  • Cortical activation and gait parameters were analyzed for differences between and within groups using statistical methods.

Limitations

  1. Sample Size: The relatively small sample size (36 participants) may limit the generalizability of the findings.
  2. Hypertension Severity: The study included only hypertensive patients with grade 1 hypertension, which may not represent the full spectrum of hypertension severity.
  3. Medication Impact: The study did not account for the type, dose, and duration of antihypertensive medications, which could influence cognitive and gait performance.
  4. Age Range: Participants were aged between sixty and seventy years, so findings may not apply to older adults beyond this age range.
  5. Cross-Sectional Design: The study’s cross-sectional nature does not allow for determination of causality between hypertension and cognitive or gait impairments.

Conclusion: Hypertension Impact on Cognitive & Gait Functions in Old Age

This study highlights the significant impact of hypertension on cognitive and gait functions in older adults, demonstrating that hypertensive individuals exhibit higher brain activation to manage dual cognitive and walking tasks.

This increased cortical activation indicates an inefficient allocation of brain resources, leading to poorer cognitive performance and reduced gait stability.

Understanding these mechanisms underscores the importance of early detection and targeted interventions to mitigate cognitive decline and mobility impairments in hypertensive older adults.

Interventions such as optimized medication management, regular physical exercise, cognitive training, and lifestyle modifications can play crucial roles in normalizing brain activity and improving overall quality of life.

By addressing both the cognitive and physical aspects of health, we can better support hypertensive older adults in maintaining their independence and reducing the risk of further cognitive and functional decline.

References