Physiological assessments

Context

When talking about new assistive technologies, one inevitably expects figures about potential benefits. In fact, it can sometimes be difficult to say what the real gains are, given the huge variety of work situations that two different operators in the same job may face. It should be noted that these benefits also vary according to the individual.

Most of the objective data you will find often relate to evaluations carried out in the laboratory, and therefore in simulated work situations. These results are important as they allow research to be carried out and new technologies to be developed, but they do not always reflect the reality of your activity.

In France and abroad, institutes such as the INRS (Institut National de Recherche et Sécurité) have been working for several years to provide food for thought, both on questions of acceptability and on more objective data thanks to laboratory evaluations.

The AFNOR (Agence Française de Normalisation) expert commission, of which HMT is a member, is currently working on a voluntary standard that will include these assessments. The Z68-800 agreement, published in 2017, is a kind of instruction manual for understanding how to assess the interaction of these technologies with humans.

What’s the point?

In order to answer this question, a distinction must be made between two types of assessment, those carried out in the laboratory and those carried out in a real work situation.

The main purpose of the former is to advance scientific research. They tend to verify certain hypotheses in order to inform the general public of the benefits or risks to be aware of before thinking of buying equipment. They can also be carried out by the manufacturers themselves in order to verify or explore certain areas of development. Unfortunately, they are sometimes wrongly used by some, as marketing arguments, which in reality cannot be transposed to situations other than the one targeted in the experiment. They are also compulsory to obtain « medical device » certification for certain devices, for example.

« In situ » evaluations are intended to prove the effectiveness of a device in a given work situation, in order to validate its potential acquisition, for example. They can be carried out by laboratories, by independent companies, or directly by ergonomists or health services.

How?

Whatever the type of evaluation, a strict protocol should be drawn up, respecting scientific rigour, in which the specific features of the targeted work situation, the different hypotheses, the equipment, the method of acquisition and analysis, the population sample, etc., are mentioned.

In order to validate or invalidate certain hypotheses, as many parameters as possible should be controlled. The samples must be large enough to allow conclusions to be drawn about significant results.

Objective evaluation methods (electromyography, cardiac cost, chronograms, etc.) are sometimes preferred to subjective analysis methods (interviews, questionnaires, observations, etc.). With regard to these new physical assistance technologies, even if it would indeed be tempting to summarise everything with objective measurements, which can sometimes seem more concrete, it is always preferable and more relevant to couple the two methods. We are talking here about devices that are intended to be worn by humans, for which feeling is an essential aspect of acceptance.

What limits?

It can sometimes be very complicated for a company to set up scientific protocols. The resources, both in terms of knowledge and time, are not always sufficient to carry out these experiments in-house.

Laboratory experiments are very important for research and development, but they cannot be representative of all activities. It is therefore sometimes necessary to carry out experiments « in situ ». However, it is often complex to control all the parameters of the real activity or even to gather a sufficiently large number of subjects to draw meaningful conclusions.

Scientific equipment represents a significant financial cost. Objective evaluation methods are therefore not easily accessible to all companies.

An intermediate solution for your projects to integrate physical assistance devices may be to start assessing acceptability and acceptance issues subjectively. The INRS TF 274 document (« Processus d’acceptabilité et d’acceptation des exosquelettes : évaluation par questionnaire » WIOLAND L., DEBAY L., ATAIN- KOUADIO JJ. - 2019) seems to be a good compromise to start your evaluation process of the integration of a physical assistance device. However, it should not replace the prior analysis and understanding of the need.