Safe neuromuscular electrical stimulator designed for the elderly.

Authors: Krenn M 1, Haller M 1, Bijak M 1, Unger E 1, Hofer C 2,3, Kern H 2,4, Mayr W 5.

Source: Artif Organs. 2011 Mar; 35(3):253-6.

Keywords: Neuromuscular electrical stimulation, Aging, muscle, Electrical stimulation, Compliance management,
M-wave, Myokinematic signal


A stimulator for neuromuscular electrical stimulation (NMES) was designed, especially suiting the requirements
of elderly people with reduced cognitive abilities and diminished fine motor skills.The aging of skeletal muscle is
characterized by a progressive decline in muscle mass, force, and condition. Muscle training with NMES reduces the
degradation process. The discussed system is intended for evoked muscle training of the anterior and posterior thigh.
The core of the stimulator is based on amicrocontroller with two modular output stages. The system has two chargebalanced biphasic voltage-controlled stimulation channels. Additionally, the evoked myoelectric signal (M-wave) and the myokinematic signal (surface acceleration) are measured. A central controller unit allows using the stimulator
as a stand-alone device.To set up the training sequences and to evaluate the compliance data, a personal computer is
connected to the stimulator via a universal serial bus.To help elderly people handle the stimulator by themselves, the user interface is kept very simple. For safety reasons, the electrode impedance is monitored during stimulation. A
comprehensive compliance management with included measurements of muscle activity and stimulation intensity
enables a scientific use of the stimulator in clinical trials.


1 Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
2 Ludwig Boltzmann Institute of Electrostimulation and Physical Rehabilitation, Vienna, Austria
3 Otto Bock HealthCare Products GmbH, Vienna, Austria
4 Department of Physical Medicine and Rehabilitation,Wilhelminenspital, Vienna,Austria