This study shows that a quantitative test of fast alternating forearm movements is feasible in female patients with dementia who can understand and follow simple verbal commands. Almost all the 26 patients, in spite of their advanced age and cognitive decline, were able to perform the test. The patients showed impairment in ability to perform rapidly alternating forearm movements and were slower than healthy women, adjusted for age. Cognitive and presumably behavioral factors could have influenced the test situation. However, the limiting factor for the few patients who could not complete the test seemed to be related more to physical problems than to cognition. The finding that the demented patients generally cooperated well and had no difficulty with comprehension and execution of a test of movement speed and limb coordination is in agreement with that reported by others.2
Kischka et al,2
using electrophysiological techniques, found that tasks related to bradykinesia in the upper extremities could be completed by all but the most severely demented AD patients. Franssen et al,4
using timed clinical measurements, found participants with mild AD to cooperate well but to be more distractible and to have some mild motor impersistence.
Our demented patients were slower than controls when performing alternating forearm movements, which is in agreement with other studies.3
Franssen et al4
used timed trials of palmar to dorsal turns of the hand at maximum speed and found significantly greater prevalence of decreased performance in subjects with mild cognitive impairment and patients with mild AD compared with cognitively intact subjects. Kluger et al,3
using the number of correct turns in 10 seconds of alternating hand movements, found the mean value of correct turns to be lower in mildly cognitively impaired patients and patients with mild AD compared with healthy subjects. The reduction in frequency (lower number of cycles) found in our test of fast alternating forearm movements is interpreted as a reduced ability to execute rapid alternating movements with the limb, ie, a slowing of motor performance in the upper extremities.
Hemsdorfer et al20
found a difference between right and left hand performance, which is in agreement with our findings. The mean values for number of cycles performed by both patients and controls show that they completed a larger number of cycles with the right hand, and thus were faster with this hand compared with the left. All subjects were asked about hand preference and almost all, except two of the older female controls, reported being right-handed. No separate test for assessing hand dominance was performed. Fast alternating forearm movements represent a complex motor task that demands attention, timing, sequencing, and self -monitoring of motor behavior while changing the direction of movement during performance. A possible explanation for right hand performance being better than left hand performance might be that performing the test with the nondominant hand is less automatic and therefore more cognitively demanding.
In the test of intrareliability, we found a mean value for the number of cycles at three different sessions for the right hand and left hand in younger healthy females to be in good agreement with other reports.3
Our subjects were somewhat slower with the left hand, which is in agreement with the finding by others of a difference in right and left arm performance.20
Beuter et al33
found a mean frequency of 3.1 Hz for the right hand and 3.0 Hz for the left hand in their controls (mean age 54 ± 4 years). Kluger et al,3
using a clinical test of alternating hand movements as part of a test battery, found a mean value of number of correct turns in 10 seconds to be 29.1 in healthy men and women (mean age 69.9 ± 8.6 years). The slight difference in frequencies, compared with our study, might be due to the different methodology used and age and gender differences.
Our findings of a somewhat lower intrarater reliability coefficient over time in younger women are in agreement with the findings of Hermsdorfer et al.20
They found the reliability coefficient to be r = 0.65 (P
< 0.001) when studying test–retest reliability in the dominant hand about 4 weeks after the first examination. Their subjects were tested only twice, whereas our subjects were tested on three occasions. We found a slight increase in the mean numbers of cycles in three trials over a 3-week period, which might indicate a learning effect of frequent testing over time.
We found test–retest reliability at one session to be high for both the older female patients and the controls. Franssen et al4
also found high reliability when testing alternating pronation and supination of the forearm at maximum speed in a clinical setting. In a group of older subjects at stages 1–6 of the Global Deterioration Scale (representing stages from no memory loss through to moderately severe dementia), high ICC coefficients were found for both interrater reliability (0.72) and intrarater reliability (0.97). Our findings and those of others indicate that quantification of forearm pronation and supination is a reliable method and can be recommended as a test of upper extremity function both in older patients and healthy subjects. However, in this study, intrarater reliability was not assessed in the elderly female subjects due to low compliance and lack of willingness to come back several times.
In the group aged 80–89 years, we found associations between movement speed in the upper and lower extremities for patients but not for controls. We found the correlation coefficients between alternating forearm movements and self-selected walking speed to be higher than the coefficients for maximal walking speed in the total sample. There is probably an increased variation in the intersubject maximal walking speed that would explain the reduced correlations with alternating forearm movements compared with self-selected walking speed.
When the association was studied according to type of dementia, a high correlation coefficient was found between alternating forearm movements and lower extremity function, but only in the group of patients with probable AD. No associations were found in the group with other types of dementia. The explanation for this observation is probably that the group was heterogeneous, and consisted of patients with various types of dementia other than AD.
Correlations of forearm movements and measures of cognition or dementia severity were not analyzed in this study, because of its small sample size and thus low power. Another limitation is that we only included women. Men have been found to be faster than women on performing alternating forearm movements,20
and Beuter et al21
found an effect of both age and gender.
Motor function differs between healthy older adults and adults with cognitive impairment and dementia.8
Complex motor functions as well as motor functions associated with executive function are affected early in the process of cognitive decline, and patients with dementia perform worse than healthy older subjects.8
Our finding that motor slowing affects both the upper and lower extremities in patients with dementia is in agreement with reports from others.8
Our interpretation of this association is that a test of alternating forearm movements might be useful as a proxy for assessment of lower extremity function, given that walking disability is common among demented patients.13
We acknowledge that bradykinesia is only one of many causes (eg, pain, fractures, arthritis) of impaired gait and impaired mobility. However, alternating forearm movements, as a marker for bradykinesia, could provide additional information on decline in motor function in general and be a proxy for lower extremity function when lower extremity testing is not possible. This research device, assessing alternating forearm movements, has produced promising results, and is primarily recommended for use in longitudinal and interventional research. Future studies will reveal if it is usable in clinical settings.
The proportion of elderly subjects has been small or lacking in previous studies.3
To our knowledge, no one has studied rapid alternating forearm movements in women with the same advanced age as our subjects, both healthy and demented, or in regard to right and left hand performance. Only a few earlier studies have shown that alternating forearm movements can be used in subjects suffering from moderate to severe dementia. This study confirms that alternating forearm movements are applicable in patients with dementia. This is demonstrated by data both from test–retest with high ICCs, thus showing the test to be reliable, and in the significant differences found between patients and controls, showing that the test can discriminate. Patients with dementia are frail and have impaired motor function. We have shown that impaired motor function can be assessed. This information is important in patient care to avoid falls and fractures.
Earlier clinical studies3
using rapid alternating hand movements did not report results separately for the right and left hand, which might be questioned, because others20
have found a difference between left and right hand performance. We found significant associations between number of cycles and mobility tests for the left hand but not for the right hand. The associations for the right hand are in the same direction though, and lack of significance might be due to a lack of statistical power. We found the same type and magnitude of association for number of cycles at 10 seconds as well as 15 seconds in both controls and patients. Due to information about motor impersistence,4
and the fact that fatigue might affect test performance in demented patients, a testing duration of 10 seconds would be recommended.