Executive dysfunction assessed by Clock‐Drawing Test in older non‐demented subjects with metabolic syndrome is not mediated by white matter lesions

Abstract

Aims: Metabolic syndrome (MetS) has been associated with greater occurrence of white matter hyperintensities (WMH). It remains uncertain whether MetS as a construct is associated with poorer cognitive performances. This study explores whether MetS is associated with poorer performances in global and domain-specific cognitive tests in older nondemented subjects independently of its individual components, WMH severity and other variables. Methods: MetS was diagnosed according to the National Cholesterol Education Program AdultTreatment Panel III definition. Brain magnetic resonance studies (1.5T) were performed. Deep and periventricular WMH were graded using the Fazekas scale. Subjects underwent the Mini-Mental State Examination, the Babcock Short Story Recall test and the Clock-Drawing Test (CDT).Results: Eighty community-dwellers aged 67-91 years were studied. Subjects with MetS (n = 35) had more severe WMH, and poorer performances on the CDT (P = 0.003) and the Babcock Short Story Recall test (P = 0.027). After multiple adjustment, MetS was inversely associated with CDT scores (B = −1.285; 95% confidence interval = −1.996-−0.575; P = 0.001) but not with episodic memory. Results were not affected by WMH severity. Interestingly, none of the individual components of MetS predicted poorer cognitive performances.Conclusions: Impairment in executive functions assessed by CDT may represent an early and specific sign of cognitive decline in older individuals with MetS. Future longitudinal studies are needed to better establish the predictive role of MetS on dementia and to demonstrate the possibility of dementia prevention by targeting MetS.

The Metabolic Syndrome Predicts Longitudinal Changes in Clock Drawing Test Performance in Older Nondemented Hypertensive Individuals

“…As expected authors have consistently indicated a close relationship between MetS and impairment in executive functions (4,5). Longitudinal population-based investigations have reported a significant prospective association of MetS to incident dementia (6), whereas others have not (7,8).…”

“…CDT, a well-validated instrument to assess clinical cognitive impairment (5,10), reliably explores executive functioning, as making demands visuospatial attention, motor skills, conceptualization and planning (5). Cerebral microvascular damage is closely associated with executive dysfunction (3,4).…”

“…MetS is accompanied by peripheral insulin-resistance, chronic activation of micro-inflammatory, oxidative and pro-thrombotic mechanisms and deregulation of the renin-angiotensin-aldosterone axis. All of such mechanisms may exert detrimental effects on cognitive function in individuals with MetS, in addition to more severe cerebral vascular damage (1,4,5).…”

“…MetS has been associated with greater occurrence and severity of WMHs (3). There are inconsistent results about whether MetS as an entity influences cognitive function and dementia risk (4)(5)(6)(7)(8).…”

The test of time: a history of clock drawing

“…It has also been utilized with patients suffering from other brain disorders including postoperative delirium (Manos, 1998), Huntington's disease (Rouleau et al, 1992), Parkinson's disease (Saka and Elibol, 2009), stroke (Cooke et al, 2010), traumatic brain injury (Wagner et al, 2011), schizophrenia (Herrmann et al, 1999), and metabolic syndrome (Viscogliosi et al, 2015).…”