Obstructive Lung Disease Tied to Cognitive Impairment

Obstructive lung disease may be linked with problems with memory and information processing, new evidence suggests. The more diminished the airflow, the greater the impairment.

“Persons with obstructive lung disease experience cognitive impairment mainly in memory and information processing, which is partially related to impaired lung function,” said Fiona Cleutjens, MSc, of the Center of Expertise in Chronic Organ Failure in Horn, the Netherlands.

“We know from other studies that cognitive impairment may have negative consequences for daily functioning, health status, and treatment adherence.”

Earlier studies suggested that persons with obstructive lung disease often experience problems with a range of mental processes but looked only at global cognitive function. The new study looked at specific cognitive functions that affect persons with obstructive lung disease.

Cleutjens and colleagues conducted a large prospective cohort study of more than 500,000 Scottish, English, and Welsh persons aged 40 to 70 years that focused on genetics, environmental exposures, and lifestyle. They identified more than 5000 men and women who had obstructive lung disease and more than 37,000 comparable persons who did not have lung disease. All completed several tests to examine cognitive performance and lung function.

Persons with obstructive lung disease had significantly worse scores on memory tests as well as slower reaction speeds compared with those without lung disease, which is an indirect indication of the cognitive processing speed, Ms Cleutjens said. They also scored worse on tests that reflect the capacity to understand and remember the spatial relations among objects. They also scored significantly more poorly for all but the test of fluid intelligence, which Ms Cleutjens described as reflecting the capacity to solve problems that require logic and reasoning ability.

Those with the least severe obstructive airway disease had significantly better fluid intelligence scores than those in the intermediate group and significantly better numeric memory than those in the most impaired group.

Ms Cleutjens noted that cognitive problems associated with obstructive lung disease can be debilitating, particularly for a patient who is already dealing with the symptoms of lung disease. She added that obstructive lung disease often exists alongside other conditions.

Ms Cleutjens recommended routine screening for cognitive problems in patients with obstructive lung disease and suggested that a simple screening questionnaire would be a good first step. Then any patients showing problems could be tested further with a neurocognitive battery to determine which aspects of cognition are impaired or a physician may decide to test only those patients who report cognitive difficulties or who have other risk factors for cognitive impairment, such as vascular problems.

Medications also may affect cognitive performance. For example, anticholinergic drugs often prescribed for obstructive lung disease are associated with memory loss in some patients.

Ms Cleutjens noted, “Clinicians and health care professionals need to be alert to the possible impact of cognitive impairment in the self-management, clinical management, and pulmonary rehabilitation of obstructive lung disease patients.”

The researchers presented their results at the 2013 European Respiratory Society Annual Congress.