Psychomotor symptoms in depressed elderly patients: assessment of the construct validity of the Dutch CORE by accelerometry

Background: Psychomotor symptoms are putative distinguishing features of melancholia that may guide treatment decisions. Hence, there is a need for valid instruments to assess psychomotor symptoms. The objective of this study is to examine the construct validity of the CORE, an observational instrument designed to quantify psychomotor symptoms in depression.

Methods: Associations between CORE scores and levels of motor activity measured by accelerometry were examined in a sample of 25 elderly depressed in-patients, for various time intervals, during 24h of follow-up.

Results: Total CORE scores (as well as CORE retardation and agitation sub-scale scores) were negatively correlated with activity scores, with depression severity increasing the correlational strength substantively. For total CORE scores and retardation sub-scale scores, the highest associations were quantified across morning intervals.

Limitations: Given the nature of the study mild levels of depression were overrepresented, monitoring of motor activity lasted only 24h and non-motor activity items in the CORE were not measured.

Conclusion: Associations between CORE total scores and retardation sub-scale scores support the validity of the CORE as well as quantifying associations between severity of psychomotor disturbance and clinical depression severity. Study results also support the application of accelerometry tools in quantifying components of clinical depression.