Project TREM-END

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Assessment of a commercial orthosis for pathological tremor suppression

This initiative is part of the European project TREM_END, whose coordinator has been the Valencian company EMO. The project involved the companies EMO,  OKO Solution and Cultraro, the RTD centers IBV and  ISRI and the Neurology Service of the Hospital General Universitario de Valencia.

The results show that the orthosis is effective and reduces essential tremor in the wrist more than 30%, allowing patients increase their degree of independence.


Essential tremor is a disease that typically causes an involuntary tremor in the hands and arms. At present the treatment of the disease are the most common pharmacological and surgical. However, these treatments are not effective in 25% of cases with severe essential tremor.

Therefore, the European project TREMEND was focused at developing an orthosis for tremor reduction at the hand and  acceptable for use in real life.

Development (Material and methods)

The TREMEND project depart from previous results obtained by the IBV in European projects in DRIFTS and TREMOR. In these projects pathological tremor has been  efficiently suppressed  in laboratory conditions. In this case the challenge was to apply the knowledge to develop an orthosis that would be acceptable for use in daily life and their selling price would make her commercially viable.

The concept of the project supports tremend orthotics is to use a rotary damper working in tremor frequencies allowing to reduce the involuntary movements of the wrist when the person tries to perform any activity.

The development of the project was divided into three main phases: Design and development of damper, Design and Prototype of the orthosis with integrated damper and Validation of the orthosis.

Design and development of the damping system.

Throughout this phase, the IBV developed a biomechanical model of the tremor that was based on the characteristics of the soft tissues of the areas near the wrist, and the effect of tremor in the upper limb. With this information the consortium could calculate the involuntary movements produced in the wrist depending on the severity of tremor.

The information generated helped ISRI and Cultraro the development of a rotary damper that combined dry friction and viscous damping.

Pressure sensibility measurements and design concepts for the dampers

 Design and Prototype of the orthosis with integrated damping system.

Throughout this phase defined requirements to be met by the orthosis. The IBV coordinated this phase, and from, the feedback from all project participants could identify existing needs from different points of view:

  • Patients: We studied the characteristics to be met by the orthosis to be acceptable to them and what could be more useful situations.
  • Professionals: We analyzed how they should prescribe and / or adapt the orthosis. Also defined the type of patients who could benefit from this brace.
  • Business: We considered several key issues for the product is commercially viable, such as: the cost of manufacturing, the adaptation process and product placement, materials used, the final size of the brace, etc..
  • Biomechanics: Analysis of pressure he had to place the brace to not cause pain to the users from tests that could measure the electrical activity of the brain. In addition, we identified the functional requirements to be met by the brace and damper together so that their effect would be expected.

Having identified the requirements of the brace began the design of it. Initially, the IBV developed a first prototype orthosis with commercial focus to perform some tests and  design concept assessment. Once it was established that the preliminary results of these tests were acceptable, the EMO transform functional prototypes of IBV in designs closer to market reality. In fact, there were several design changes until you get a product that covered optimally defined requirements.

First draft of the orthosis and final prototype

Validation of the orthotics.

The valuation of the orthosis was made possible thanks to the collaboration of 12 patients with essential tremor, which were provided by the Fundación de Investigación Hospital General Universitario (FIHGU).

They worked to develop a methodology for validation of the orthosis. This assessment was divided into three blocks. The first block was applying the scale Fahn Tolosa, on this scale the patient performs a series of  exercises and answers to questions about their degree of tremor. In the second block, the patient has to follow the outline of a spiral drawn by the computer with the mouse. In the third block, the patient must make two movements. The first movement was pointing the nose with the hand, starting from a position with arms outstretched at 90 degrees to the ground. The second movement was  arms outstreched up to a 90 degree position relative to the ground, starting in this case from a rest position. To collect all these motions two inertial sensors are placed (IMUs) on the arm to be evaluated, one in the midline of the dorsal surface of the forearm and the other in the third metacarpal.

During each test, the patients performed the three blocks explained twice, first without orthoses and then with the brace put in hand to evaluate. Before the end of each trial was conducted a questionnaire to users, which asked about the usability and comfort of the orthosis.

This test was repeatied three times per patient within a one month period (every two weeks).

Examples of spirals for the same patient with and without the orthosis


The conducted validation yielded subjective results from patients opinion and objective results obtained by recording from inertial sensors.The objective results led to the conclusion that the brace is able to reduce hand tremor more than 30%.

Regarding subjective outcomes, all items analyzed were positive. The main point is that the orthosis does not cure but it reduces tremor improvin the abilities of patient to perform activities of daily living.  In fact, all patients indicated that the design of the orthosis is acceptable for use in daily basis. In addition, all participating patients kept volutarily the orthosis after the completion of the tests. Moreover, in all cases the patients commented that the brace gave them more confidence to perform daily living tasks that were affected by the tremor. Finally, in some cases, patients commented that the brace allowed to do some tasks that were very difficult without them.

Tremor reduction of the orthois


A new effective orthosis for tremor suppression has been developed. Unlike other alternatives listed in the scientific literature, the orthosis are suitable for use in daily life and will be put in the market very soon.

The orthosis developed took into account market-related constraints and the production process so it has managed to generate a new technically and economically viable product that solves a problem that had no solution so far.


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