The appropriate and timely diagnosis and management of older persons with impaired cognition can make a critical difference to their overall health and ability to function independently.
Common causes of impaired cognition in older persons can be broadly classified into delirium, dementia and depression.
Delirium is an acute or sub-acute change in the mental state that is common in frail older persons. It can arise as a result of a myriad of conditions that include infections, strokes, medication side-effects, heart failure, abnormal metabolic states (e.g. poorly controlled diabetes mellitus, abnormally low or high sodium levels).
It is known that persons who suffer from delirium are often seriously ill. They are at greater risk of developing complications from their acute illness and may be at increased risk of developing dementia later on.
It is important for older persons with a recent change in mental state to be assessed by a medical practitioner at the earliest possible instance, as many of the causes of delirium are amenable to medical interventions.
Dementia affects 4 to 13% of older persons above the age of 65, depending on the system of classification that is being applied to make the diagnosis. While it is common for older persons to suffer from some degree of memory loss, it does not mean that memory loss equates dementia. It is also equally important to realize that ageing does not inadvertently lead to dementia and that significant memory loss is not "normal" in older persons. Persons are diagnosed to have dementia when they have a sustained loss of intellectual abilities and memory that is of sufficient severity to affect their ability to function in their usual manner in everyday life.
As much as 3 to 10 % of persons presenting with features that are consistent with a diagnosis of dementia actually have conditions that are potentially reversible. These may include brain tumours, blood clots within the brain or metabolic disorders. Even when the cognitive syndrome is not reversible, modalities exist that may help to retard the progression of a proportion of dementia sufferers.
In addition, apart from the decline in intellectual function, dementia sufferers often have significant neuro-psychiatric and behavioural problems that result in severe stress to their care-givers and may place the sufferers and their loved ones at risk of harm.
Early recognition of this cognitive syndrome, coupled with proper assessment and intervention may result in improvement in outcomes as well as a reduction in carer stress and an improved quality of life for the patients as well as their care-givers.
Depression is a common example of the non-specific and atypical presentation of illness in older persons. Features suggestive of depression in older persons may arise from a range of treatable physical illnesses, but may also be the presenting manifestations of a major depressive illness. Depression in older persons is thus often under-diagnosed.
Recognition and appropriate management of interactions between the symptoms and signs of depression secondary to physical illnesses and those caused primarily by psychiatric disorders can help prevent medical morbidity and result in improved quality of life.
Examples of physical illnesses that may manifest with depressive symptoms include heart failure, metabolic conditions such as hyperthyroidism or hypothyroidism, abnormal sodium levels, chronic pain syndromes or even medication side effects.
For primary affective disorders, effective strategies for intervention that include pharmacotherapy and non-pharmacological means are readily available.