Table 3.

Operationalised criteria for delirium (C) ¹, when applied to the Cuban population based study data set, by clinical dementia status

	Prevalence (%) in those with clinically diagnosed dementia N = 130	Prevalence (%) (high education controls) N = 50	Prevalence (%) (low education controls) N = 95
C criterion requires that the deficits do not occur exclusively during the course of a delirium
C_1 no onset in the last month, and	100	98	100
C_2 no sudden onset in 1–3 days, and	93	94	93
C_3 not changeable over 24 hours, alert at one time, drowsy and confused the next, or	75	85	87
C_4 no confusion worse towards night or evening	52	70	61

1. Only ascertained among those with a current episode characterized by functional and cognitive decline