Are scores on the physical performance test useful in determination of risk of future falls in individuals with dementia?

BACKGROUND AND PURPOSE

Presence of dementia influences postural control and increases fall risk. The 7-item physical performance test (PPT) is a valid measure of balance in older adults; however, its validity has not been established in people with dementia. The purpose of this research was to establish predictive validity of the PPT for falls in people with dementia.

METHODS

Subjects with dementia (N=34, mean MMSE score 18.4 + 3.3) were tested with the PPT and then followed for four months for fall occurrences.

DATA ANALYSIS

A stepwise logistic regression (variables of age, previous history of a fall, and PPT score) determined predictors of a fall. Sensitivity, specificity, and likelihood ratios for each of the significant measures were calculated.

RESULTS

Twelve subjects (35%) reported at least one fall in the four months. History of a fall in the previous six months was the only significant predictor of a subsequent fall (p=.044), increasing the odds by almost five times. Calculated sensitivity and specificity for history of a fall were 58% and 77% respectively and positive and negative likelihood ratios were 2.52 and .58 respectively.

DISCUSSION

A fall in the previous six months was the strongest predictor of a fall in the subsequent four months in people with dementia. Score on the PPT was not a significant predictor of falls. Further research is warranted, however, since 8 of the 13 subjects falsely identified as a faller by their PPT score (false positives) had other strong indicators of postural control dysfunction.