People who are born blind have four times as many nightmares as sighted people, according to a new study conducted by the Danish Centre for Sleep Medicine. The findings confirm that nightmares are related to a person’s daytime stress.
“The study confirms an already existing hypothesis that people’s nightmares are associated with emotions they experience while awake. And blind people apparently experience more threatening or dangerous situations during the day than people with normal sight,” said lead author Amani Meaidi, a research assistant at the center.
The researchers recruited 11 participants who were born blind, 14 who had become blind, and 25 normally sighted people, and asked them to record their dreams over a period of four weeks. Several surprising findings emerged.
The results showed that approximately 25 percent of a born-blind person’s dreams are nightmares, compared to only six percent for a sighted person. The dreams of people who became blind later in life were more similar to sighted people with nightmares at seven percent.
The nightmares were typically related to fears experienced in everyday life, such as being in an embarrassing social situation or a car accident.
Meaidi noted that dreams are a largely sensory experience, a way for the brain to process the day’s physical experiences. Those who were born blind did not have dreams with visual content, while those who became blind later in life reported fewer and fewer visual dreams over time.
“The study also points out that the sensory input and experiences we get while awake are decisive when it comes to what we dream. So people without visual sensory input dream to a much greater extent in terms of sounds, tastes, smells, and touch,” said Meaidi.
“Because people who lose their sight later in life have previously seen their surroundings it might be that their brains do not experience being threatened by circumstances to the same degree as people who are born blind,” said Meaidi.
“For this reason they may not need to process impressions from everyday life to the same extent by means of nightmares.”
The findings were surprising to the blind participants, who were unaware that they had a greater number of nightmares than sighted people.
“This isn’t something that causes problems for them in their everyday lives, for which reason several of them are surprised to hear the result,” says Maeidi.
Source: Danish Centre for Sleep Medicine