Are Fluctuations in Motor Performance a Diagnostic Sign of Delirium?

Background: Although delirium is known as a mental disorder, recent evidence suggests that it is associated with short- and long-term impairment of functional status. Objective: To evaluate whether a pattern of fluctuations in motor performance are a diagnostic sign of delirium. Design: Case-controlled study with prospective evaluations of 4 groups of patients. Setting: Department of Rehabilitation and Aged Care. Methods: Fifteen patients with incident delirium alone (Del group) and 15 patients with incident delirium superimposed on dementia (DSD group) were compared with 15 patients with neither delirium nor dementia (No Del-No Dem group) and 15 patients with dementia but no delirium (Dem group), respectively. Eligibility criteria were age 65 years or older, ability on admission to maintain sitting position for at least 10 minutes, and absence of visual/hearing impairment or delirium on admission. All patients underwent a multidimensional assessment on admission and serial evaluations of motor performance using Trunk Control Test (TCT) and Tinetti scale. These assessments were fixed at 5 different times, coincident with admission (T 0), predelirium (T 1), onset of delirium (T 2), resolution of delirium (T 3), and discharge (T 4). Results: Patients in the Dem, DSD, and Del groups were significantly more impaired at T 0 in cognitive and functional status and motor performance compared with No Del-No Dem patients. At T 1 all groups improved, although in different ways. At T 2 only in the Del and DSD groups, but not in the others, there was a pattern of decline in TCT and Tinetti scores (P < .0005 at t test for pair comparison for both tests) and a specular pattern of improvement at T 3 (P < .0005 at t test for pair comparison for both tests). Patients in the Del and DSD groups had the poorest attentive and executive performances at T 2, which significantly improved at T 3. In No Del-No Dem and Dem groups, attentive and executive functions did not change from T 2 to T 3.. Conclusion: Patients with delirium exhibit a pattern of fluctuating motor performance that is chronologically related with the onset and the end of delirium, ie, they decline when delirium develops and improve when delirium ends. This pattern seems to be typical of delirium, as it is appreciable in subjects with dementia developing delirium but not in patients with dementia alone. A fluctuation of motor performance should be considered a diagnostic sign of delirium.