The mediating effect of depression in the association between sleep and mild cognitive impairment: the moderating role of physical strength on the direct pathway

Mild cognitive impairment (MCI) is a form of cognitive decline that is associated with cognitive deficits but overall independence in daily functioning. Due to the unclear nature of the progression and occurrence of MCI, research has been focusing on identifying risk factors for its development. Key risk factors include lifestyle, psychological and genetic factors. Among them research has detected both sleep disturbances and depressive symptoms as significant risk factors for the development of MCI. Building upon on this, the current research investigated whether depressive symptoms could act as a mediator in the association of sleep disturbances and MCI. On top of that, further health indicators, such as physical strength, have been strongly associated with cognitive decline. To further explore the risk factors for the development of MCI the current research examined the possible moderating role of physical strength on the direct effect of sleep disturbances on MCI. For the...Show moreMild cognitive impairment (MCI) is a form of cognitive decline that is associated with cognitive deficits but overall independence in daily functioning. Due to the unclear nature of the progression and occurrence of MCI, research has been focusing on identifying risk factors for its development. Key risk factors include lifestyle, psychological and genetic factors. Among them research has detected both sleep disturbances and depressive symptoms as significant risk factors for the development of MCI. Building upon on this, the current research investigated whether depressive symptoms could act as a mediator in the association of sleep disturbances and MCI. On top of that, further health indicators, such as physical strength, have been strongly associated with cognitive decline. To further explore the risk factors for the development of MCI the current research examined the possible moderating role of physical strength on the direct effect of sleep disturbances on MCI. For the purposes of this cross-sectional study data from 294 participants were used. The participants’ cognitive state was assessed through MMSE and ACE-r, subjective cognitive complaints, and an assessment by both a neurologist and a neuropsychologist. For the assessment of possible depressive symptoms, the participants completed the HADS questionnaire. Sleep disturbances were self-reported in the MOS questionnaire. Lastly, physical strength was measured with a dynamometer. The data collection was completed from Aiginiteion Hospital in Greece for the purposes of a larger longitudinal study. Before the analysis, a data cleaning procedure was conducted. In the next step, a mediation analysis, and a subsequent mediation analysis with a moderator on the direct path were performed using the PROCESS macro in SPSS. The results revealed a partial mediation for the first analysis, identifying a significant relationship between sleep disturbances and MCI even after adding the mediator. For the second analysis, strength did not show a significant moderating role on the direct path, leaving this relationship significant but not affected by strength. The results suggest that low sleep quality can contribute to the development of MCI through depressive symptoms, highlighting the multidimensional nature of MCI. However, no added value on the significant link between sleep disturbances and MCI by physical strength could be established. Important clinical implications of the above-mentioned findings include the establishment of the multifactorial nature of MCI, which in return highlights the need of a personalised multidimensional assessment and treatment. Lastly, worth-mentioning limitations are the use of self- report measures to assess both sleep disturbances and depressive symptoms, as well as the lack of generalisable results.Show less

Leiden University Student Repository

Documents

In Collections

The mediating effect of depression in the association between sleep and mild cognitive impairment: the moderating role of physical strength on the direct pathway