Visuospatial Ability in Relation to Fall Risk and Dementia

In the October 2009 issue of the Archives, Johnson and colleagues¹ describe a longitudinal study of the transition from healthy aging to Alzheimer disease. When comparing various cognitive domains between stable participants and participants with dementia, they found that visuospatial abilities demonstrated an inflection point 3 years before clinical diagnosis of dementia.¹ These findings are potentially profound because visuospatial decline occurred 1 year prior to global cognitive declines and 2 years before declines in verbal and working memory functions.¹ This suggests that the current widespread use of episodic memory screening as a clinical method of detecting cognitive decline may, in fact, be inadequate. These findings also have implications when considering fall risk among older adults. Currently, falls are a major health care concern, as 30% of community-dwelling adults older than 65 years experience 1 or more falls each year.² Additionally, mild cognitive impairment, having dementia, or having a Mini-Mental State Examination score of 24 or less further increases the risk of falling.³

Interestingly, there is recent evidence suggesting that poor visuospatial skills are associated with increased fall risk among older adults.⁴ Consider this point, together with the findings presented by Johnson et al, and an interesting relationship emerges. If declining visuospatial ability occurs approximately 3 years prior to the diagnosis of clinical dementia,¹ it is possible that during this 3-year span, older individuals may also be experiencing elevated risk of falls due to their poor visuospatial function. Perhaps the occurrence of falls among some older adults is an indicator of preclinical dementia. Suppose an older adult has repeated falls, yet this individual does not display any deficits in episodic memory or executive function as measured using a clinical screen such as the Mini-Mental State Examination. He or she may, in fact, be experiencing a decline in visuospatial abilities. This decline, a possible inflection point for the diagnosis of clinical dementia,¹ contributes to increased fall risk,⁴ making the occurrence of falls a potential risk factor for dementia. In other words, increased fall risk could be a possible sign of dementia among patients who do not exhibit declining cognitive function or mild cognitive impairment as measured using standard clinical assessments. This most definitely warrants further investigation; however, it highlights the potential implications of Johnson and colleagues' findings and further emphasizes the important role of neuropsychology in understanding fall risk and dementia progression. Indeed, a longitudinal study examining the occurrence of falls in relation to measured visuospatial abilities and the eventual clinical diagnosis of dementia is necessary.

Correspondence: Mr Naslund, Diamond Health Care Center, 8257-2775 Laurel St, Vancouver, BC V5Z 1M9, Canada (john.naslund@vch.ca).

Financial Disclosure: None reported.