, president of the and associate professor at the 51在线 College of Behavioral and Community Sciences, collected 43 million pieces of location data by monitoring the movements of 53 ALF residents for a year. He did so by tracking their wristbands with a real time location system (RTLS) sensor network. The technology was created by Ubisense and is currently used by BMW. Kearns calculated the straightness of their walk in near real-time using fractal dimension, a mathematical tool used to explain how complex travel patterns change based on the scale of measurement.
鈥淔rom my previous research, my colleagues and I found the poorer the score on the Mini-Mental State Exam, which assesses cognitive function, the higher the fractal dimension value,鈥� Kearns said. 鈥淚t鈥檚 through this calculation I learned that increased errors navigating the environment are related to long-term cognitive impairment due to dementia.鈥�
Kearns makes this conclusion following his study at the Sunrise Village Assisted Living Facility in Tampa, where automated computerized reports on each resident鈥檚 fractal dimension value were generated. Future daily reports will allow administrators to more closely monitor increasing signs of wandering and investigate the potential causes, such as changes to a resident鈥檚 diet, medications or sleeping habits. By making adjustments, fractal dimension values can be reduced, improving their navigation and ultimately prevent an impending fall.
Most ALFs have high turnover rates, some exceeding 150 percent per year. So the 鈥渃orporate memory鈥� about an elder鈥檚 health status may be erased after just a few months. ALFs are also generally understaffed and cannot provide continuous individualized attention and care.
鈥淲e found the study by Dr. Kearns to be eye-opening,鈥� said Bunny Markarian, former administrator at Sunrise Village Assisted Living. 鈥淏y monitoring our residents鈥� walking pattern and any deviation, we, along with the visiting physician or ARNP, could intercede after investigating the cause. In many cases, this intervention prevented hospitalization of the resident or readmission. And the residents involved in the study were excited to have a role.鈥�
RTLS is much more accurate than GPS and updates 100 times per second. It pinpoints one鈥檚 location, indoors or outdoors, within six inches. GPS is limited to the outdoors and has a one-meter resolution. RTLS is most effective for open floorplans, typically found in ALFs, since there are usually fewer obstacles to negatively affect accuracy.
Kearns believes the wristband technology will eventually be used in at-home care. He鈥檒l present his findings at the International Society for Gerontechnology 11th World Conference May 7-9 in St. Petersburg, Fla.
Graph shows day to day variation in Fractal Dimension for a person who fell twice: the vertical bars denote days the person fell.
-Story by Tina Meketa, University Communications and Marketing, and photos by Eric Younghans, USF Health Communications and Marketing