Acquisition and short-term retention of inhaler techniques require intact executive function in elderly subjects

patients with dementia are almost invariably unable to use any form of inhaler. Some elderly patients are unable to learn to use a metered dose inhaler or Turbohaler despite a normal abbreviated mental test score. Studies have shown that in many people this is due to unrecognised cognitive impairment and/or dyspraxia. The executive domains of cognition are particularly important in planning and sequencing; it might be expected therefore that disordered frontal (executive) function could be a predictor of poor inhaler technique in subjects with no overt features of dementia.

to explore the relationship between cognitive, and executive, function and the ability to acquire metered dose inhaler and Turbohaler technique in old age.

a prospective randomised observational study with blinded evaluation.

30 inhaler-naive inpatients (21 female) with a mean age of 85 (range 75-94) and having a normal (8-10) abbreviated mental test score.

subjects received standardised metered dose inhaler and Turbohaler training and were scored on an analogue scale (for metered dose inhaler) or for competence (Turbohaler) the following day. The Mini-Mental State Examination and EXIT25 (for executive function) were performed by separate observers.

significant correlation was found between the metered dose inhaler score and Mini-Mental State Examination (r 0.540, P<0.002) and EXIT25 (r -0.702, P<0.0001). Threshold effects emerged for the metered dose inhaler in that 18/19 with a competent score compared to 2/11 scored as incompetent had a Mini-Mental State Examination of >23 (P<0.01) and 19/19 compared to 0/11 had an EXIT25 of <15 (P<0.01). Similarly, for the Turbohaler 21/21 of the competent subjects had a Mini-Mental State Examination of >23 compared with 3/9 incompetent subjects (P<0.01), with 21/21 competent compared with 0/9 incompetent having an EXIT25 <15 (P<0.01).

acquisition and short-term retention of metered dose inhaler and Turbohaler techniques is unlikely to be successful in frail elderly people who have an abnormal Mini-Mental State Examination and/or EXIT25 test. The latter test, when abnormal, is probably the superior predictor of inability to learn inhaler techniques.