Implanted Device Allows Paralyzed Hands to Grasp
Nov. 7, 2001 -- It's not exactly The Bionic Man, but for 51 patients who received the experimental "neuroprosthetic hand grasp system," it comes close. The surgically-implanted device, which has already received pre-approval from the FDA, enabled these quadriplegic patients to grasp and release one of their hands for the first time since their devastating spinal cord injuries.
Researchers in the U.S., Britain, and Australia implanted the device -- consisting of electrodes, sensors, and other high-tech gadgetry -- in 51 otherwise-healthy adult patients with spinal cord injuries that had resulted in paralysis or near-paralysis of all four limbs. Although the patients had retained a degree of function following their accident -- they could move a shoulder, and flex an elbow or wrist -- none had voluntary control over their hands.
According to the researchers, the neuroprosthetic system allows the user to perform two distinct grasps: a thumb-to-index finger 'lateral pinch' used to hold a key or other small object, and a fingers-to-thumb 'palmar grasp,' used to hold a glass of water.
Following surgery, each patient underwent between three and six months of rehabilitation, followed by training to maximize his or her benefits from the device. Training included such everyday tasks as eating with a fork, writing with a pen, using a computer diskette, and brushing teeth.
When the patient moves a shoulder up and down or back and forth, "these movements are sensed by [a sensor implanted in the] shoulder position ... and sent to the external controller," which is a small portable device that can be carried on a belt, the researchers write. The signal is then sent to leads implanted in the hand and forearm muscles, making the hand open and close. The patient controls the degree of hand movement by adjusting his shoulder movement.
Over the next three years, a few patients developed infections at the location of an implant that required electrodes to be removed and replaced, and some others experienced swelling, discomfort, and skin irritation related to the device. Overall, however, the vast majority of patients were pleased with the device.
According to the authors, "more than 90% were satisfied with the neuroprosthesis, and most use it regularly. Many participants [have] substantially improved their life circumstances. Three have moved out of nursing homes and into more independent living situations. Another regained the ability to take care of her own children. Many participants began additional schooling, and in a few cases, have returned to work."
The findings appear in the October issue of Archives of Physical Medicine and Rehabilitation.