This study examined the relationship between cerebrospinal fluid (CSF) norepinephrine (NE) levels and cognitive performance across adult lifespan. Norepinephrine is a neurotransmitter in the central noradrenergic system that aids attention, working memory, and executive function. However, too much activity can impair cognition. Previous research has suggested that older adults tend to have higher noradrenergic activity than younger adults. However, it was uncertain whether this difference affects cognitive performance. The researchers studied 258 cognitively normal participants ranging from 21 to 100 years old to determine whether higher NE concentrations were correlated with worse cognitive function.

Participants underwent a series of neuropsychological tests measuring attention, processing speed, executive function, memory, and language. CSF samples were collected via lumbar puncture. NE concentrations were measured using high-performance liquid chromatography. Statistical analyses included multiple linear regression models to evaluate the relationship between NE levels and cognitive performance, adjusting for age, gender, education, and ethnicity.
 

The results demonstrated that higher CSF NE levels were significantly associated with poorer performance on tasks of attention, processing speeds, and executive functioning–including the Trail Making A and B tests and the Stroop Word-Color Interference task. This relationship remained prevalent after adjusting for demographic variables. CSF NE levels were higher in older adults, which was consistent with previous studies. Gender influenced memory outcomes, with higher NE linked with worse memory in males but not females. Ultimately, the study supports the idea that elevated central norepinephrine may negatively affect cognitive function, particularly in aging adults.