The PSAD Device

Enabling objective assessment of different
components of spasticity

Joint and muscle stiffness examination made more specific and precise

PSAD is a handheld medical device for bedside objective assessment of different components of spasticity.

The PSAD is designed to be used as part of neurological examination by researches and clinicians and uses new biomechanical and electrophysiological technology.

PSAD device and tablet

The PSAD device enables an objective assessment of


The range of joint movement


Stiffness of the muscle-tendon complex throughout the range of movement


Reflex mediated stiffness

Key elements of the PSAD device

  • A PSAD handle with integrated dynamometer, accelerometer, gyroscope and electromyography
  • Orthosis dedicated to a certain limb
  • EMG cable and single-use sensors
  • Software for data collection
PSAD device and tablet

The PSAD measures the range of joint movement, resistance to movement and muscular activity. Muscular activity can be assessed using EMG – but it is not mandatory for the usage of the PSAD device.

Joint and muscle stiffness assessment with the PSAD

Joint and muscle stiffness examination with the PSAD

  • An orthosis is mounted to the limb and the PSAD handle is attached to the orthosis.
  • The examiner flexes and extends the ankle joint by moving the PSAD handle while the applied force and movement are measured.
  • The PSAD communicates via WIFI with the tablet computer, which acquires all data and provides feedback for the examiner during the measurements.
  • Data on the full joint torque and joint angle are measured and the stiffness is calculated.
  • Data is stored and provides extensive possibilities for off-line analysis.
  • In addition, muscular activity can simultaneously be measured and analyzed by applying EMG electrodes to the limb and connected to the PSAD handle.

Application of PSAD device in research

The design and idea behind the PSAD is based on many years of internationally recognized research on spasticity.

The PSAD has been tested in people with cerebral palsy, multiple sclerosis, stroke, spinal cord injury and traumatic brain injuries.

High reproducibility within the same person and between persons has been demonstrated.

The following scientific publications provide further information about the PSAD device and the research that has resulted in its development:
  • J. Lorentzen et al, 2012 “Assessment of a portable device for the quantitative measurement of ankle joint stiffness in spastic individuals”, Clinical Neurophysiology, 2012, 123(7): 1371–82.
  • Willerslev-Olsen M et al, 2013 ”Passive muscle properties are altered in children with cerebral palsy before the age of 3 years and are difficult to distinguish clinically from spasticity.” Dev Med Child Neurol 2013; 55: 617–23
  • Willerslev-Olsen M et al, 2018 ”Impaired muscle growth precedes development of increased stiffness of the triceps surae musculotendinous unit in children with cerebral palsy”, Dev Med Child Neurol. 2018 Jul;60(7):672-679
  • Yamaguchi T et al, 2018 ”Spasticity in adults with cerebral palsy and multiple sclerosis measured by objective clinically applicable technique” Clinical Neurophysiology, 2018, 129 (9): 2010-21

Ready to use the PSAD device?

The PSAD device is CE marked and available for purchase.

The PSAD device includes

PSAD handle including charger and EMG cable

Software for data display, calculations and storage

Two orthoses for the ankle (size child and adult)
Measuring tape

3 bags of EMG electrodes (single use). More electrodes are to be sourced separately

Instruction for use
Suitcase for transportation and storage

Additional services

Mechanical couplings for custom made orthoses for other limbs


Yearly calibration service of the PSAD handheld device and software updates

Training course in using the PSAD device in practice

Contact us

Contact us for more information and purchase of the PSAD device.

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The Story Behind

The PSAD concept is patent protected. The PSAD is developed by Movotec A/S in cooperation with Copenhagen University and professor Jens Bo Nielsen and the Elsass Foundation.

The Elsass Foundation

The Elsass Foundation was established by Miss Helene Elsass, who herself suffered from cerebral palsy. Her wish was to help people with cerebral palsy. The Elsass Foundation is a research and scientific expertise center, and the foundation also supports people with cerebral palsy individually.


Our mission is to improve the lives and possibilities for people with movement disorders by providing state of the art diagnostic methods and tools.