Wednesday, 9 August 2017

Smart Robotic Outfit For Stroke Patients

Humans are evolutionarily designed for upright walking on two legs for the efficient movement. Stroke can take away this normal walking ability in a fraction of the time. In a multidisciplinary approach, the group of researchers have developed a novel powered wearable robotic exosuit which has high potential to restore normal walking in stroke patients.

By Ratneshwar Thakur Published in The Hawk

(Wyss Institute Core Faculty member Conor Walsh and Graduate Student Jaehyun Bae)

In a new study, research teams led by Conor Walsh collaborating with Boston University faculty members Terry Ellis, Lou Awad, and Ken Holt have demonstrated that exosuit can help to improve walking in stroke patients. This research is published in the Journal “Science Translational Medicine.”

A stroke is a "brain attack" which occurs when the blood supply to the brain is cut off. When brain cells die during a stroke, abilities controlled by that area of the brain such as memory and muscle control are lost. Clinicians have observed that about 80% of stroke patients suffer from hemiparesis- a situation- where one limb loses its ability to function normally. 

Despite rehabilitation, the vast majority of stroke survivors retain deficits that prevent walking at speeds suitable for normal and safe community ambulation i.e. independent outdoor mobility. 

In a collaborative effort to help stroke patients regain their walking abilities, team of researchers at the Wyss Institute for Biologically Inspired Engineering, the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and Boston University’s (BU) College of Health & Rehabilitation Sciences: Sargent College has developed a lightweight, soft wearable robot (exosuit) that interfaces to the paretic limb of persons after stroke via garment-like, functional textile anchors. 

These robotic suits (Exosuits) function in coordination with the paretic limb of persons after stroke to overcome insufficiencies in forward movement and ground clearance during hemiparetic walking. Exosuits produce gait-restorative joint torques by transmitting mechanical power from waist-mounted body-worn or off-board actuators to the wearer through the interaction of the textile anchors and a cable-based transmission. 

“We wanted to help people by finding the ways to rehabilitate the stroke patients. This technology might allow us to restore the component of normal walking. This is different and wearable by patients, much lighter than a typical exoskeleton. The long-term goal of our study is to develop a soft wearable robotic suit that can be worn as clothing, even at home,” said Terry Ellis, Ph.D., P.T., N.C.S., Director of the Center for Neurorehabilitation at BU’s College of Health & Rehabilitation Sciences: Sargent College and Assistant Professor at BU. 

“One person is different than other; new challenge is how you adapt this technology person to person considering their specific walking problems. We are working on various algorithms to know the best time to enter the gait rehabilitation for certain aspect,” said Ellis in a telephonic interview. 

In ongoing and future research the team is trying to develop personalize exosuit assistance to specific gait abnormalities. Also, they are trying to investigate assistance at other joints such as the hip and knee to assess long-term therapeutic applications of their technology. 

Thursday, 3 August 2017

Human Heart's 'Battery' Has Multiple Backups: A New Hope To Maintain Consistent Heart Rhythm

Researchers at The Ohio State University Wexner Medical Center have discovered the human sinoatrial node is hardwired with a backup system. In the groundbreaking study, they have found that three diverse regions of pacemakers acting as batteries and up to five conduction pathways that act as wires to connect the signal to the atria.

By Ratneshwar Thakur Published in The Hawk

High-resolution immunostaining image of the human sinoatrial node.
( Image credit: Dr. Vadim V. Fedorov)

A heartbeat begins when the sinoatrial node fires off an electrical impulse that disperses across the atria, the blood-collecting chambers. The sinoatrial node (SAN) is the primary pacemaker of the human heart and responsible for initiating and regulating cardiac rhythm. 

Since the discovery of the SAN by Keith and Flack in 1907, multiple studies have investigated the SAN structure and its role in the formation and regulation of sinus rhythm in human and different animal hearts. However, until now, scientists didn’t know for sure how the human SAN protected the heart’s rhythm or how the system failed. 

Due to the methodological limitations of studying the heart in patients, the current perception of the SAN is a very simplistic. 

“Our study revealed the functional and structural complexity of the human SAN. The human SAN is hardwired with a backup system -- three diverse regions of pacemakers acting as batteries and up to five conduction pathways that act as wires to connect the signal to the atria. This built-in redundancy maintains consistent heart rhythm in most people for decades, even under trying conditions,” said Dr. Vadim Fedorov, an associate professor in Ohio State’s Department of Physiology and Cell Biology.

The study is published in the Journal “Science Translational Medicine.”

It has been challenging to study human SAN pacemaker complex as it is a heterogeneous 3D structure that lies within the atrial wall, and clinical electrode recordings are limited to only surface atrial activation. Furthermore, the human SAN differs greatly from well-studied experimental animal models.

To overcome these challenges, Dr. Fedorov and his team integrated the high-resolution optical mapping with 3D structural reconstruction and molecular mapping, to reveal the functional, structural, and molecular characteristics underlying robustness of the human SAN pacemaker and conduction complex.

Defects in the pacemaker can lead to heart rhythm disorders that are commonly treated by doctors through implantation of electronic pacemaker devices. 

Dr. Fedorov’s team believes that their research may contribute significantly to the development of novel treatments for human SAN dysfunction and cardiac arrhythmias. 

“Specifically, our study is providing the foundation for seeking out ways to improve or restore SAN function by targeted treatments in patients with impaired SAN and thus avoiding an electronic pacemaker implant. Our hope is that someday, electronic pacemaker implants could be obsolete,” said Dr. Vadim Fedorov.