As we age, the decline in balance ability and muscle strength in the lower limbs can increase the risk of dementia. To help assess an elderly person's balance and lower body abilities, we present a quick one-minute chair test, which can serve as an elementary screening method. Here are the two ways to perform the test:

1. Chair Balance Test:
- Have the elderly person sit on an everyday chair with a backrest.
- Ask them to lean on the chair and then stand up.
- Instruct them to walk over to touch a pair of slippers and return to sit back on the chair.
- Record the duration of the entire process.
- Completion within ten seconds indicates good balance and lower body ability, while exceeding 20 seconds suggests a certain risk.

2. Crossed Hands Test:
- Instruct the elderly person to cross their hands and call out numbers one through five.
- Time the process of completing these five movements.
- The time allowed varies with age: under 60 years old should complete within 11 seconds, 60 to 69 years old within 11.4 seconds.

The mechanisms behind the decline in balance and dementia are complex. While Alzheimer's disease and other forms of dementia are generally linked to cognitive decline, monitoring walking footprints may reveal anomalies like heavy footfalls or rigid walking postures, indicating possible brain region involvement by pathological substances. Moreover, the decline in lower limb and balance abilities can limit outdoor activities, leading to reduced mental and physical exercise.

To combat these issues, encouraging middle-aged and elderly individuals, especially those under 55 years old, to engage in regular mental and physical exercise is crucial. Taking advantage of the window period when these activities are still feasible can significantly impact long-term brain health. Activities like brisk walking and swimming can be beneficial during this stage, as it becomes increasingly challenging to make up for muscle atrophy at a later age.