Background
Prevalence of cognitive impairment increases along with
aging; for elderly persons, it causes difficulty in ADL and
dependence on their family members or caregivers. Cognitive
decline is also known as an evident risk factor for
falling [1], which often results in being bedridden owing
to hip fractures and/or other life-threatening conditions.
As Lundin-Olsson et al. have long ago advised in a
simple and clear manner, “Stop walking when talking”
[2], elderly people with dementia are susceptible to falling
when they divide their attention between two processes,
which require executive cerebral functions.
Conversely, several observational studies with cognitively
intact older subjects have to date revealed that high
physical activity reduced the incidence of dementia [3, 4].
Furthermore, exercise intervention improves not only the
essential physical elements needed to avoid falling, such
as balance, muscle strength, and agility, but also cognitive
functions, even in the aged individuals at high risk for
dementia [5, 6]. For most of these studies, the extent of
physical activity was estimated by the time spent on exercise.
Moreover, in many cases, the modality of exercise
was aerobic exercises, such as walking, and the details of
the exercise they performed were not considered relevant.
Therefore, the question of the kinds of exercises
that have advantages in improving cognitive functions
needs to be resolved. In particular, an evaluation of the
effect of dual-task exercise training, which imposes simultaneous
motor and cognitive tasks, is necessary because
as indicated above, it is probable that dual-task training
raises executive functions, including attention, in elderly
people.