Chronic pain is one of the main factors influencing workers' retention at work. Considering that the prevalence of suffering from chronic pain increases with age, older workers are most likely to be absent from work because of their pain.

Transcranial direct current stimulation (tDCS) is a treatment option to reduce chronic pain.

This study aims to document the effect of tDCS on pain and work retention in older workers and to compare the traditional tDCS protocol (5 sessions) with an enhanced protocol (11 sessions).

Chronic pain affects many spheres of the lives of affected individuals and those around them. In Canada, the prevalence of chronic pain is estimated at 15% of adults aged 18 and over. Among seniors, the prevalence of this health problem can reach up to 50% and affect one in two seniors. Chronic pain is one of the leading causes of work disability. In this context, pain reduction remains one of the most effective methods to enable the worker to stay at work. Considering the aging Quebec population, labor needs and the average retirement age which is increasingly postponed, it becomes crucial to take an interest in aging workers and their continued employment.

Transcranial direct current stimulation (tDCS) is a non-invasive neurostimulation method that has shown promise in reducing chronic pain. Recently, several research teams have shown that tDCS has beneficial effects on pain, physical function and social participation in seniors. Despite all these recent advances, very few studies have focused on optimizing tDCS treatment modalities and no studies have focused on the impact of tDCS on return to work or retention. The vast majority of studies using tDCS to reduce pain give one tDCS session per day for 5 consecutive days. This study aims to document the effect of tDCS on pain and work retention in older workers and to compare the traditional tDCS protocol (5 sessions) with an enhanced protocol (11 sessions).

Inclusion Criteria:

• To be more than 55 years old
• To have chronic pain
• To have employment relationship
• To have pain that interferes with work tasks

Exclusion Criteria:

- tDCS contraindications (epilepsy, metallic implant in the head, pacemaker, cochlear implant)

Upon request to the corresponding author

Upon request