Portable NIR Brain Imaging Device Offers Insight into Parksinsonian Syndromes

A portable near-infrared brain imaging device has been used to compare healthy brain activity and stability with that of people with Parkinsonian syndromes.

The findings highlight the role of the prefrontal cortex in balance control, and may aid in the detection and treatment of Parkinsonian symptoms in the elderly.

The prefrontal cortex, highlighted in red, is responsible for high-level functions like memory, attention and problem solving. Images courtesy of Albert Einstein College of Medicine.

Parkinsonian syndromes are conditions that do not rise to the level of a Parkinson's disease diagnosis but exhibit similar symptoms like rigidity, tremor and difficulty walking.

Past attempts to compare brain activity and stability in people with Parkinsonian syndromes have been limited, as neuroimaging tools could only be used when a study participant was lying flat. In these cases, the subject could only imagine that he or she was performing tasks such as walking and standing.

Now a portable system created by researchers at Drexel University in Philadelphia has overcome this challenge in a study conducted by researchers at the Albert Einstein College of Medicine.

The device employs functional near-infrared (fNIR) spectroscopy, which uses light to monitor changes in blood oxygenation in the brain as individuals perform tasks, take tests or receive stimulation. The prefrontal cortex is the area responsible for higher-level processing, such as memory, attention, problem-solving and decision-making. When a person is learning a new skill, for instance, neural activity is greater in this region.

A study participant stands while wearing the portable functional near-infrared (fNIR) spectroscopy system, which uses light to monitor changes in blood oxygenation in the brain as individuals perform tasks.

Unlike fMRI (functional magnetic resonance imaging), the fNIR system is fully portable. Participants wear a headband, allowing them to talk and move around while a computer collects data in real time.

The researchers used the fNIR technology to compare 126 healthy adults to 117 individuals with mild Parkinson's symptoms and 26 with more severe symptoms. While wearing the fNIR headband, participants were asked to stand and look straight ahead while counting for 10 seconds. They then walked on a mat that captured their gait speed, pace and stride length. The fNIR system recorded their brain oxygen levels during the entire testing period.

The researchers found that those with Parkinsonian symptoms demonstrated significantly higher prefrontal oxygenation levels to maintain stability when standing than participants with mild and no symptoms.

"In fact, brain activity in the frontal brain region was nearly twice as large," said Jeannette R. Mahoney, an assistant professor of neurology at Einstein.

In an upcoming clinical trial, the researchers will use a computerized cognitive training program and the fNIR system to identify how cognitive training affects brain activation during walking.

The portable technology could aid in diagnosing Parkinsonian syndromes or developing interventions.

The study was published in Brain Research (doi: 10.1016/j.brainres.2015.10.053).