Voyer and colleagues (2016) report an interesting and important comparison of ten attention/concentration tests for DSM-5 delirium. I have a number of questions and comments as follows:
What training did the research assistants have? DSM-5 diagnosis is generally regarded as a decision by medical specialists. When the person has prior dementia, identifying delirium is a high-level medical skill. Behavioral and psychological symptoms of dementia can closely mimic delirium unless the examiner focuses on behavioral triggers and the speed of cognitive decline.
The requirement of taking medications twice a day may have eliminated some delirium patients with impaired swallowing or refusal to take medications.
Lumping dementia, confusion, and disorientation into one label “cognitive impairment” is problematic and reduces the usefulness of Table 3.
The authors used prior diagnosis of dementia as a gold standard when in fact many people with that label have mild cognitive impairment.
The ten “concentration” subtests in the Hierarchic Dementia Scale (HDS) (Cole and Dastoor, 1987) are not purely indices of concentration. Serial seven subtraction is impaired in low education with normal concentration. Months of the year backwards is often ranked as both an attention and executive function test and it requires semantic knowledge. Digit span forward is a rapid attention test missing from the HDS which has been of great value in my delirium research.
As expected DSM-5 delirium was more common among medical inpatients than long-term care residents (14.9% vs. 4.0%, Table 1).
The Central Coast Australia Delirium Intervention Study (Regal, 2015) supported the gold standard to prove delirium was the speed and amplitude of both onset and recovery. In CADIS, the mean recovery of five-digit span forward was two days, six-DSF 5.6 days and Delirium Index 8.0 days.