Summary

This research project followed on an initial epidemiological study that demonstrated the high prevalence of musculoskeletal disorders (MSDs), psychological health problems (PHPs), and physical and psychosocial risk factors among agents at municipal public security emergency call centres (MPSECCs). It sought to understand how these risks manifest themselves in the work in order to propose courses of action for reducing the adverse effects on the agents' health. With that in mind, the research was based on the ergonomic approach to work activity, including physiological measurements, and was supplemented by a study of the work psychodynamics.

In ergonomics, the physical and psychosocial risk factors identified in epidemiological studies relate to the presence of strains and workloads of a musculoskeletal and mental nature that are associated with the presence of MSDs and/or PHPs.

The physical strains at the source of potentially harmful musculoskeletal loads in MPSECCs originate in computer work problems, to which are added the strains specific to emergency communications. These strains are related to, on the one hand, accessibility problems originating from the number of pieces of equipment to be placed on the workstation and, on the other hand, the prolonged maintenance of the seated posture required by the agent's obligatory presence at the station.

To reduce the risk of MSDs related to this last type of strain, some MPSECCs have installed workstations that allow the work to be performed while sitting or standing.

The mental strains originate in three processes: first, workload, which, in corporate contexts, is defined as the number of actions to be performed during a specified period of time and which here relates to the frequency of incoming calls and the number of searches required to answer them; second, the cognitive workload, which concerns the processing of information, which, in the present case, means the complexity of handling calls; and, third, the psychic workload, which refers to the emotional dimension of handling emergency calls and the psychic processes brought into play by the agent in order to deal with the strains present in the work.

The descriptions of work situations with demonstrated regulation problems were at the basis of the development of courses of action aimed at reducing MSD and PHP risks. These courses of action were developed with the assistance of the follow-up committee and validated by a meeting with a group of agents.

The research was carried out with the participation of the five MPSECCs involved in the preceding study. It had two components: an ergonomic study involving the collection of physiological data and a study of the work psychodynamics. The ergonomic and physiological study was based on the participation of 11 agents, six men and five women, of whom nine were experienced employees and two were novices. The agents held generalist, call-taking, and dispatching positions. The following data were collected: description of the work and of the office layout; observation of work postures; use of the sit-stand workstation adjustment options; telephone communications; subjective evaluations of the mental workload, musculoskeletal pain and fatigue; trapezius electromyography (EMG); heart rate or electrocardiography (ECG); and the agents' comments during auto-confrontation interviews. The observations were made and measurements taken during a work shift, while the heart rate was recorded over 24 hours. The study of the work psychodynamics entailed organizing four group interviews in four MPSECCs. The groups consisted of four to six male and female agents with between two and 25 years' experience. The content of the interviews was analyzed based on the work psychodynamics reference framework in accordance with current methodology.

The results of the ergonomic study show that, from a risk prevention standpoint, introducing adjustable sit-stand workstations provides a greater margin of manoeuvre to agents in dealing with the work's various strains and with musculoskeletal pain sensations and fatigue. However, the design of the workstations does not appear entirely satisfactory for reducing MSD risks. The design of the office tables should be rethought in light of the agents' activity and of technological developments.

The physiology/ergonomic and work psychodynamics studies provide a clearer understanding of the presence of psychosocial strains. As measured by subjective evaluation of the mental workload, these psychosocial strains are associated with an increase in sensations of musculoskeletal pain. More specifically, pain in the upper back, neck and shoulder region correlates positively with perceptions of higher workload and call complexity, while low back pain correlates with negative emotions. This result is consistent with the increase in activity and decrease in rest time for the trapezius muscles associated with the increase in workload and call complexity. For negative emotions, none of these changes proved significant. The increase in activity and decrease in rest time for the trapezius muscles probably stem from more frequent actions involving controls. For heart rate, a significant reduction in variability was measured throughout the work shift for the experienced agents, a reduction quickly reversed after the shift ended. This shows that experienced agents are prepared to react to stress situations. During the work shift, correlations between heart rate or heart rate variability (HRV) and perception scale responses were found in only a small number of agents, attesting to a dependency on the special characteristics of the work shifts observed.

Observation of cognitive and relationship problems in the information and comments obtained through the auto-confrontation interviews allowed the work situations with a high cognitive and emotional workload to be described. Analysis of the work psychodynamics completed the picture by describing how these strains are managed relative to the psychic dimension. This made it possible to determine how agents' work experience is built up over time and to identify the sources of pleasure and the defence strategies adopted to deal with the strains specific to this occupation.

The results brought a clearer understanding of aspects of the work, which the follow-up committee used as a basis for developing courses of action. These courses of action fit with the development prospects for a profession that only began to be structured and organized in Québec relatively recently.

Initial efforts focused on improving the technology. They took the form of purchasing computer hardware that supported the agents' work and furniture adapted to the strains of continuous operation in which agents replace one another at the same workstation. The results of the psychosocial risk study show that, in a subsequent phase, efforts should be focused on cognitive and emotional support. Such support requires the development of training based on the transmission and exchange of know-how related to communication when taking calls. It also implies a deepening of relationships with first responders and especially patrol officers. The follow-up committee has developed courses of action with that in mind. More generally, this research project has made it possible to develop an ergonomic study methodology for interventions aimed at reducing psychosocial risks.