Cell phone application helps rehabilitate stroke survivors

Assistive technology developed at the University of São Paulo helps patients with reduced muscle strength or unilateral paralysis perform daily activities and regain lost body awareness.

By Maria Fernanda Ziegler  |  Agência FAPESP – Brazilian researchers have developed a cell phone application that helps rehabilitate people who have suffered a stroke. Using a sensor (accelerometer) that detects the inclination of the handset attached to the person’s clothing, the program can identify posture and advise the user on how to improve body alignment, either through voice commands, vibrations or images.

The device works to rehabilitate a problem known as hemiparesis, which is one of the most challenging sequelae of strokes and can also occur as a result of brain damage caused by diseases such as multiple sclerosis, cerebral palsy and some types of cancer. In these cases, there is a loss of muscle strength or partial paralysis on one side of the body, as well as damage to body awareness.

“The person with hemiparesis loses sensitivity and perception of spatial organization. As a result, they may tip to one side and not realize it, and even experience muscle pain from the misalignment. They may also be unable to perform everyday tasks such as walking, cooking, driving or climbing stairs without correct posture. In this way, both body awareness and trunk control, which are lost with the stroke, have to be relearned to guarantee the functionality of the upper limbs,” explains Amanda Polin Pereira, currently a professor in the Department of Occupational Therapy at the Federal University of São Carlos (UFSCar) and first author of the article published in the journal JMIR Aging.

The development of the software, conceived from a need observed by Pereira, took place during the doctorate of Olibário José Machado Neto, a FAPESP scholarship holder at the Institute of Mathematical and Computer Sciences of the University of São Paulo (ICMC-USP). The research was carried out within the framework of two projects supported by the Foundation (16/50489-4 and 16/00351-6) and involved collaborators from the Ribeirão Preto School of Medicine (FMRP-USP).

“From a software development point of view, it was a co-development job that really brought together two different areas of knowledge to meet the needs of patients. This gave us a lot of agility and support in developing the application, which is completely unique. There’s nothing like it in the clinic to help treat and rehabilitate these patients,” emphasizes Maria da Graça Campos Pimentel, professor at ICMC-USP and Machado Neto’s advisor.

The tests were conducted at a rehabilitation center. Throughout the process, the researchers interviewed physiotherapists and occupational therapists to understand treatment needs. Patients undergoing rehabilitation were also consulted.

“In addition to generating a wealth of data to further our understanding of hemiparesis in the future, the app helps patients improve their posture during these sessions and allows therapists to focus on other rehabilitation issues, making the process more efficient and accurate. We’re also starting a study on the longer-term use of the app at home,” says Pereira.

Less is more

Over the course of the project, three versions of the app were developed. “We started with the idea of a wearable app, but we realized that the simpler it was, the better it would be accepted by patients. That’s why we focused on developing the software, and instead of creating special clothing, we decided to sew pockets into tops or tank tops that could attach the cell phone to the patient’s torso,” says Pimentel.

“Ultimately, we created an accessible wearable technology that uses the resources of low-cost smartphones and built-in accelerometers to continuously monitor changes [from right to left and forward and backward], using the device’s visual, tactile, and auditory feedback to guide patients while standing,” the researcher explains.

photo: Amanda Pereira

According to Pimentel, the ultimate goal of the work is to make the app available for free and to take advantage of new studies based on the data generated on hemiparesis. “What we need now is collaboration to keep the app up to date, something that takes time and financial investment,” she says.

The article “Wearable Smartphone-Based Multisensory Feedback System for Torso Posture Correction: Iterative Design and Within-Subjects Study” can be read at: aging.jmir.org/2025/1/e55455/.