Having close friendships and staying in contact with family members help prevent the risk of developing symptoms of Alzheimer’s disease, according to a new study.

Many elderly people have the pathological symptoms of Alzheimer’s disease but do not experience the cognitive impairment or dementia common to the disease, according to researchers at Rush University Medical Center’s Alzheimer’s Disease Center in Chicago,

Researchers studied 89 elderly people without known dementia who provided information about their social networks and underwent 21 cognitive performance tests each year. Their brains were analyzed after they died. The larger a person’s social network, the less effect the tangles and plaques — indicative of Alzheimer’s — had on their cognitive test scores.

The study is online in The Lancet Neurology.