Many dementia patients are not receiving "key" health assessments when they are in hospital, a new report has found.
Tests to see whether patients are suffering from delirium and assessments of their mental state are at an "alarmingly low" level, according to the latest national dementia audit.
Many elderly patients with dementia develop confusion during a stay in hospital but less than half are assessed for delirium - a state of mental confusion that can happen if someone becomes medically unwell.
And only half of the 8,000 dementia patients who took part in the audit had received an assessment of their mental state, the authors said.
"Assessment for delirium and of mental state is alarmingly low," the authors said.
"Delirium is associated with greater risks of longer admission, hospital acquired infections, admission to long term care, and death.
"Failure to assess and plan for mental health needs may also prevent appropriate assessment and care for physical health needs."
The report identifies "continuing problems" in the quality of care received by people with dementia in hospitals in England and Wales.
Researchers, from the Royal College of Psychiatrists, also found that two in five hospitals do not provide dementia awareness training to new staff. And 11% of hospitals did not provide such training to nurses.
But the authors noted that since the last audit, conducted in 2011, "several aspects of care have improved", including a decrease in the number of patients given anti-psychotic drugs.