The tests themselves are highly reliable and valid. A recent study showed these three tests in particular have both high interrater and intrarater reliability. This means that the tests give the same results when given by different people and that the same person giving the test more than once will get the same results.
These tests do measure a patient’s function. For example the hand-to-neck position is one used to comb or fix the hair. Reaching behind the back is a motion needed to perform toileting functions. Reaching the hand across the body toward the other shoulder is important when bathing and dressing.
Patient cooperation and motivation are important factors in these types of function-based tests. The therapist will be able to compare the results of your mother’s movement tests from day-to-day and week-to-week to measure progress. Unusual results or wide swings from one extreme to another may be caused by the dementia. If that happens, then the test results aren’t valid.