The tidal volume of normal adult's peaceful breathing is about 400~600ml. Peaceful breathing rate is 12 to 18 times per minute, so the ventilation volume per minute is 6 to 9 liters. According to this calculation, the amount of hydrogen inhaled by these subjects is about 240-360 milliliters per minute.

The study used two cognitive detection methods, namely MMSE and ADAS-Cog.

The Mini-Mental State Examination (MMSE) was compiled by Folstein Equally in 1975. It is one of the most influential standardized mental state examination tools. It can be used for Alzheimer’s disease as a cognitive impairment examination method. The screening is simple and easy. The normal value of this table is 27-30 points, and the average number of subjects in this study is 26, indicating the presence of mild cognitive impairment. After 4 weeks of hydrogen inhalation, this value reached 29 points. It shows that cognitive impairment has been significantly improved.

ADAS-Cog is a cognitive function score scale for Alzheimer's disease, which can be used to detect the intelligence of the elderly. According to the scores of the scale, it can preliminarily judge whether the elderly have Alzheimer's disease. This assessment includes 11 tasks to assess impairments in memory, language, practice, attention and other cognitive abilities. The results of this study found that the subjects’ ability to recognize words and recall words before the treatment with hydrogen gas has been particularly improved. For example, word recall increased from 3.6 to 8.1, an increase of up to 140%.

The results of the study suggest that hydrogen inhalation may be effective for elderly cognitive impairment. It should be further verified by a larger-scale study.