Sample Size Calculation in Physical Medicine and Rehabilitation: A Systematic Review of Reporting, Characteristics, and Results in Randomized Controlled Trials

BackgroundMaintaining cognitive function is essential for healthy aging and to function autonomously within society. White matter lesions (WMLs) are associated with reduced cognitive function in older adults. However, whether their anatomical location moderates these associations is not well-established. This review systematically evaluates peer-reviewed evidence on the role of anatomical location in the association between WMLs and cognitive function.MethodsIn accordance with the preferred reporting items for systematic reviews and meta-analysis (PRISMA) statement, databases of EMBASE, PUBMED, MEDLINE, and CINAHL, and reference lists of selected papers were searched. We limited our search results to adults aged 60 years and older, and studies published in the English language from 2000 to 2011. Studies that investigated the association between cognitive function and WML location were included. Two independent reviewers extracted: 1) study characteristics including sample size, sample characteristic, and study design; 2) WML outcomes including WML location, WML quantification method (scoring or volume measurement), strength of the MRI magnet in Tesla, and MRI sequence used for WML detection; and 3) cognitive function outcomes including cognitive tests for two cognitive domains of memory and executive function/processing speed.ResultsOf the 14 studies included, seven compared the association of subcortical versus periventricular WMLs with cognitive function. Seven other studies investigated the association between WMLs in specific brain regions (e.g., frontal, parietal lobes) and cognitive function. Overall, the results show that a greater number of studies have found an association between periventricular WMLs and executive function/processing speed, than subcortical WMLs. However, whether WMLs in different brain regions have a differential effect on cognitive function remains unclear.ConclusionsEvidence suggests that periventricular WMLs may have a significant negative impact on cognitive abilities of older adults. This finding may be influenced by study heterogeneity in: 1) MRI sequences, WML quantification methods, and neuropsychological batteries; 2) modifying effect of cardiovascular risk factors; and 3) quality of studies and lack of sample size calculation.

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“…However, we do recognize that the lack of sample size calculations may be due to the dearth of data in this research area [45]. …”

Section: Discussionmentioning

confidence: 99%

The association between cognitive function and white matter lesion location in older adults: a systematic review

et al. 2012

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“…A further concern is that power calculations are still not given due importance, and when given, are manipulated . In the current survey, 11 of the 40 (27%) articles did not give a study power.…”

Section: Discussionmentioning

confidence: 80%

Are sample sizes of randomized clinical trials in rheumatoid arthritis too large?

Çelik

Yazıcı

2014

Eur J Clin Investigation

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“…For example, Stinson et al[8] recruited healthy participants to evaluate the effects of repositioning and sitting on the consistency of interface pressure. MacDonald et al [9] and Kirby et al [10] used able-bodied participants to compare the mean pressure and the wheelchair handling skills of a tilt-in-space wheelchair and a manual wheelchair equipped with a new rear anti-tip device from the perspectives of the caregiver and the user. Aissaoui et al [11] used able-bodied subjects to compare the kinematic effects of conventional and compensatory legrests.…”

Section: Discussionmentioning

confidence: 99%

Sliding and pressure evaluation on conventional and V-shaped seats of reclining wheelchairs for stroke patients with flaccid hemiplegia: a crossover trial

Huang

Yeh

Chen

et al. 2011

J NeuroEngineering Rehabil

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BackgroundReclining wheelchairs are commonly used to transport elderly stroke patients in Taiwan. However, there is concern that the patient's body in the wheelchair often slides forward when they return to a seated position, increasing the sitting pressure. Therefore, a novel reclining wheelchair with an ergonomic "V-Seat" was designed to prevent forward sliding and pressure sores. The use of these reclining chairs by stroke patients has not yet been studied. Thus, we investigated the effects of V-shaped and conventional seats in reclining wheelchairs on the extent of forward sliding and on the sitting pressure of stroke patients with flaccid hemiplegia and of able-bodied elders.MethodsWe recruited 13 able-bodied elders and 11 stroke patients with flaccid hemiplegia and performed 5 reclining cycles in both types of wheelchair. The amount of sliding along the backrest (BS) plane and the seat (SS) plane, the mean sitting pressure (MP), and the sacral peak pressure (SPP) of the subjects were recorded. We used the Wilcoxon signed-rank test to compare the BS, SS, MP, and SPP in wheelchairs with conventional and V-shaped seats, and we used the Wilcoxon rank sum test to compare the differences in BS and SS between stroke patients and able-bodied elders in both types of reclining wheelchair.ResultsThe BS, SS, and SPP of stroke patients were significantly lower in the wheelchairs with V-shaped seats than in conventional wheelchairs in most comparisons; however, the BS of able-bodied elders was higher in V-shaped seats than in conventional seats. The SS and SPP of stroke patients were significantly higher than those of able-bodied elders in both types of reclining wheelchair, and the BS of stroke patients was significantly higher than that of able-bodied elders only in conventional reclining wheelchairs.ConclusionsThe use of V-shaped seats in reclining wheelchairs can help reduce the forward sliding and sacral peak pressure of stroke patients with flaccid hemiplegia. The back displacement of able-bodied subjects when using both conventional and V-shape seats in reclining positions differs from the back displacement of stroke patients with flaccid hemiplegia when using such seats. These results are of paramount value and should be considered when prescribing the use of reclining wheelchairs to subjects with flaccid hemiplegia.

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Sample Size Calculation in Physical Medicine and Rehabilitation: A Systematic Review of Reporting, Characteristics, and Results in Randomized Controlled Trials

Cited by 50 publications

References 132 publications

The association between cognitive function and white matter lesion location in older adults: a systematic review

The association between cognitive function and white matter lesion location in older adults: a systematic review

Are sample sizes of randomized clinical trials in rheumatoid arthritis too large?

Sliding and pressure evaluation on conventional and V-shaped seats of reclining wheelchairs for stroke patients with flaccid hemiplegia: a crossover trial

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