Home-based monitoring of muscle strength in patients with ALS

Amyotrophic Lateral Sclerosis (ALS) is a progressive disease that affects motor
neurons leading to loss of muscle strength and functional abilities. Insight
into the course of muscle strength can help care providers to offer tailor-made
care. Furthermore muscle strength is an important outcome measure in trials on
efficacy of new therapies. Muscle strength is usually assessed with a Hand Held
Dynamometer (HHD). These measurements can be easily performed in a clinical
setting by physiotherapists or research nurses. However, the protocols for
assessing muscle strength are often extensive and therefore time-consuming and
burdensome for patients. Protocols measuring 20 muscle groups or more are no
exception. In addition, these manual measurement methods are difficult to
standardize and it is difficult to manually provide sufficient resistance at
high forces, making this method prone to measurement errors. Fixed dynamometry
can solve these problems. In fixed dynamometry, the dynamometer is placed in a
fixed construction, so that the measurement can be performed in a more
standardized manner and high forces can be measured.
From retrospective data research (unpublished) strength of the quadriceps
muscles appeared an important predictor of life expectancy in ALS and can
therefore provide insight into rate of disease progression.
The department of Rehabilitation, Physical Therapy and Sports of the UMC
Utrecht has recently developed a prototype to assess strength of the quadriceps
muscles using fixed dynamometry. Preliminary results in healthy subjects showed
that the reliability of this fixed dynamometer is better than that of the HHD.
However, it is not yet known whether it is feasible to use the force meter
independently at home for patients with ALS or PMA. In addition, it is not
known whether independent measurement of muscle strength with the fixed
dynamometer yields data that is sensitive enough to observe disease
progression.

Primary: To determine the feasibility of measuring muscle strength at home with
the fixed dynamometer
Secondary: Determining the sensitivity of the fixed dynamometer to detect
changes in disease progression in ALS during home measurement

Observational research. Patients will independently perform muscle strength
measurements at home, without intervention from the researchers.

In addition to 3 visits at the patient's home by the researcher, participants
will perform muscle strength measurements at home, independent of the
investigator, once every two weeks for a maximum period of 24 weeks, The total
duration of participation will involve a maximum of 190 minutes.
The participants are used to muscle strength measurements. Because the
measurements and visits take place at home, with appropriate protective
measures, participation is minimally burdensome. The results of this research
can potentially contribute to the improvement of tailor-made care and to better
outcome measures in scientific research.