Chronic Stress Impairs Temporal Memory

Temporal memory is formed from processes encoding and consolidating durations in memory. These processes can be enhanced in acute stressful contexts, which increase the arousal level, typical of the alert phase of the General Adaptation Syndrome of stress. However, prolonged stressful experiences (chronic stress) can cause damage to the storage of duration in memory. This study investigated the effects of psychological and physiological stress on the temporal memory of 50 nurses working in an emergency situation. They performed a temporal generalization task with a retention delay of 24 hours between the learning of a standard duration (4 s) and testing. Their blood was collected to examine circulating inflammatory markers related to stress. Their feeling of stress was also examined with two self-reported questionnaires, the Job Stress Scale (JSS) and the Perceived Stress Scale (PSS). The results show that temporal judgment is more variable when participants have high exposure to occupational stress (JSS). A quadratic relationship was also observed between the accuracy of time judgment and the level of perceived stress. Indeed, the proportion of accurate responses increased until a certain threshold of perceived stress, and then decreased. The results also showed a significant quadratic relationship between nitric oxide and the proportion of accurate responses. A low stress level is positively related to improving memory for a time, consistent with the reaction triggered in the alarm stage of the General Adaptation Syndrome of stress. However, above a certain level of stress, psychological and physiological stress damages temporal memory.