Alzheimer’s disease is the most common cause of cognitive decline in older adults, afflicting 10 percent of people ages 65 or older.

A study has revealed that time of year has an impact on patients’ cognitive symptoms.

In the journal PLOS Medicine, investigators reported on their analysis of results from more than 3,300 participants with Alzheimer’s disease.

They performed cognitive testing and obtained cerebrospinal fluid samples to test for Alzheimer’s biomarkers and determine links between seasons and biomarker measures.

They found that cognitive abilities were higher during the summer and fall months compared with winter and spring.

Moreover, cerebrospinal fluid amyloid levels, which are an indication of the disease, were highest in the summer.

The findings point to the importance of providing greater support for patients during the winter and spring months, but did not explain what may be driving the seasonal variations in symptoms.

Possible explanations include environmental (light, temperature), behavioral (activity, sleep), or mood factors that vary according to season.