Insight in dementia: When does it occur? Evidence for a nonlinear relationship between insight and cognitive status

Lack of insight or impaired awareness of deficits in patients with dementia is a relatively neglected area of study. The aim of this study was to eval uate insight in a group of demented patients with two assessment in scales and to assess their relationship with the cognitive level of disease severi ty. Sixty-nine consecutive patients affected by Alzheimher's disease (n = 3 7) and vascular dementia (n = 32) with a wide range of cognitive impairment (MMSE = 17.0 +/- 6.4) were recruited. Insight was evaluated with the Guide lines for the Raring of Awareness Deficits (GRAD)-specifically targeted to memory deficits-and the Clinical Insight Rating scale (CIR), evaluating a b roader spectrum of insight (reason for the visit, cognitive deficits, funct ional deficits, and perception of the progression of the disease). In the w hole sample, GRAD and CIR were significantly associated with MMSE (Spearman 's coefficient = .51, p < .001: and r = -.55, p < .001) and with Clinical D ementia Rating stale (-.57 p < .001; and r = .57 p < .001) respectively. Th e shape of the relationship of MMSE with CIR and GRAD scales was assessed w ith spline smoothers suggesting that the relationship follows a trilinear p attern and is similar for both scales. Insight Hun uniformly high for MMSE scores greater than or equal to 24, showed a linear decrease between MMSE s cores of 23 and 13 and was uniformly low for MMSE scores less than or equal to 12 The trilinear model of the association between insight and cognitive status reflects more closely the observable decline of insight and can pro vide estimates of when the decline of insight begins and ends.