Evaluating the Relationships between Balance, Cognition, and Alzheimer’s disease

Alzheimer’s disease (AD) symptoms are usually classified as cognitive decline, psychiatric manifestations (such as agitation, anxiety, and apathy), and physical impairments. Falls and related injuries are more common in Alzheimer’s disease patients than in healthy individuals of similar age.1-5 As AD progresses and balance is lost, the ability for an individual to live independently is diminished and the burden of care increases. Subjective cognitive impairment (SCI) is when a person identifies a reduction in their own cognitive functioning (usually memory) that is not yet measurable on tests, whereas mild cognitive impairment (MCI) is the decline that is mild but clinically measurable. Both SCI and MCI result in memory deficits but no noticeable functional limitations, while AD results in both loss of memory and physical functions.  This study evaluated the underlying aspects of balance control in patients with SCI, MCI and Alzheimer’s disease to determine if early intervention would be beneficial.6

Overall, results indicated that individuals with impairments of executive function (organization and behavior regulation) are likely to have balance impairments as well, increasing risk for future falls. Because reduction in balance begins at an early stage of cognitive impairment, it would be useful to initiate balance training before balance problems progress to levels that put patients at significantly greater risks for falls.

From January 2011 to August 2012, patients were recruited from Oslo University Hospital and a rural area outside of Oslo. All patients included in the study were still living in their homes and had a diagnosis of MCI, SCI, mild AD, or moderate AD. They were all still mobile without the use of a walking device. Patients were excluded from the study if they had severe AD, another type of dementia, severe hearing or vision impairment, neurological conditions such as Parkinson’s disease, stroke with motor control issues, or musculoskeletal conditions causing moderate to severe pain or limiting gait. Cognition was assessed through the Mini-Mental Status Examination, Trail Making Test, Clock Drawing Test, Word-List Learning Test, and Verbal Fluency Test. Balance was determined with the BESTest, which has 6 subscales that measure: biomechanical constraints, stability limits/verticality, anticipatory postural adjustments, postural responses, sensory orientation, and stability in gait.

The patients with mild AD had lower test scores for each measure than patients with SCI or MCI, while the patients with moderate AD had the lowest overall test scores. Furthermore, executive function was associated with each of the balance measures, even when adjusted for demographics. The stability in gait subscale (balance in motion) showed the greatest difference between the SCI, MCI, and mild and moderate AD groups. Stability limits and sensory orientation, related to balance while standing still, were affected. While these measures are impacted in people with AD, they tend to be preserved better over time for AD patients than dynamic balance control (balance while in motion). Overall, results indicated that individuals with impairments of executive function are likely to have balance impairments as well, increasing risk for future falls. Hence, because reduction in balance begins at an early stage of cognitive impairment, it would be useful to initiate balance training before balance problems progress to levels that put patients at significantly greater risks for falls.

 

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  1. Morris JC, Rubin EH, Morris EJ, Mandel SA. Senile dementia of the Alzheimer’s type: an important risk factor for serious falls. Journal of Gerontology. 1987;42:412–

 

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  1. Tolppanen AM, Lavikainen P, Soininen H, Hartikainen S. Incident hip fractures among community dwelling persons with Alzheimer’s disease in a Finnish nationwide register-based cohort. PLoS One. 2013;8:e59124.

 

  1. Tangen GG, Engedal K, Bergland A, Moger TA, Mengshoel AM. Relationships Between Balance and Cognition in Patients With Subjective Cognitive Impairment, Mild Cognitive Impairment, and Alzheimer Disease. Physical Therapy. 2014 Aug;94(8):1123-34. doi: 10.2522/ptj.20130298. Epub 2014 Apr 24

 

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