Episodes of undue daytime somnolence, staring spells, diminished awareness of surroundings and incoherent or illogical thoughts may be signs of Alzheimer’s disease, according to a study published on Jan. 19 in the journal Neurology.

Together, these symptoms come together under the umbrella term “cognitive fluctuations,” which is a spontaneous alteration in cognition, attention and arousal, as defined by the study. In layman’s terms, these syndromes are known as mental lapses or “brain farts.”

While prior studies have associated cognitive fluctuations with Lewy Body Disease, a type of dementia closely allied to both Alzheimer’s and Parkinson’s diseases, the impact of this phenomenon on healthy brain aging and Alzheimer disease was unknown.

To probe into the relationship between cognitive fluctuations and Alzheimer’s, James Galvin, associate professor of neurology and psychiatry at Washington University School of Medicine, director of the Memory Diagnostic Center and member of the Alzheimer’s Disease Research Center, pioneered a study along with his colleagues Adriana Escandon and Noor Al-Hammadi.

In the study, 511 research participants of age 78.1, plus or minus 8 years, were evaluated for the presence and severity of dementia using the Clinical Dementia Rating (CDR) and a neuropsychological test at the Washington University Alzheimer’s Disease Research Center.

Furthermore, the research participants also filled out informant assessments of fluctuations with the Mayo Fluctuations Questionnaire and day level of alertness with the Mayo Sleep Questionnaire.

Through this combination of assessments, researchers found that while only 0.7 percent of non-demented older adults had cognitive fluctuations, up to 15 percent of Alzheimer’s patients displayed such phenomenon.

After controlling for age and alertness level, researchers also found that participants with cognitive fluctuations were 4.6 times more likely to have dementia.

Although Galvin acknowledges that the presence of these fluctuations may be a normal sign of aging, he suggests that mental lapses are positively correlated with dementia.

“If you have these lapses, they don’t by themselves mean that you have Alzheimer’s disease [because] such lapses do occur in healthy older adults,” Galvin said. “But our results suggest that they are something your doctor needs to consider if he or she is evaluating you for problems with thinking and memory.”

The result of this study is significant because mental lapses have been commonly attributed to incipient Alzheimer’s disease.

“We have demonstrated for the first time that such episodes are more likely to occur in persons who are developing Alzheimer’s disease,” Galvin said.

While the study revealed some mysteries about Alzheimer’s, it also raised some questions.

“It is not yet known if the small number of non-demented older adults who experience fluctuations will go on to develop cognitive impairment,” Galvin said. “We hope to address this with longitudinal follow-up.”

In addition to following up on adults with elevated levels of cognitive fluctuations, Galvin hopes to study further these mental lapses from different angles, such as imaging strategies, to better identify treatment strategies.

Another route of research is to examine the alteration in brain function in individuals with fluctuations. To do so, Galvin plans to observe the changes in resting blood oxygen levels using functional magnetic resonance imaging (fMRI).

While many studies are necessary to reach a more definitive conclusion, Galvin is optimistic about the current findings.

“Given the strong influence fluctuations have on cognitive performance, it is possible that fluctuations could serve as an infrequent, but important clinical marker for dementia,” Galvin wrote.