The effect of non-invasive positive pressure ventilation (NIPPV) on cognitive function in amyotrophic lateral sclerosis (ALS): a prospective study
- aDepartment of Psychology, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK, bDepartment of Respiratory Medicine, Guy's, King's, and St Thomas' School of Medicine, King's College Hospital, London, SE5 9PJ, UK, cDepartment of Neurology Guy's, King's, and St Thomas' School of Medicine and Institute of Psychiatry, London SE5 8AF, UK
- Dr L Goldsteinl.goldstein{at}iop.kcl.ac.uk
- Received 19 October 2000
- Revised 3 April 2001
- Accepted 14 May 2001
Abstract
OBJECTIVES Neuropsychological investigations have shown a degree of cognitive dysfunction in a proportion of non-demented patients with ALS. Respiratory muscle weakness in ALS can lead to nocturnal hypoventilation, resulting in sleep disturbance and daytime somnolence. Sleep deprivation of this type may cause impairments in cognitive function, but this has not been formally evaluated in ALS.
METHODS Cognitive functioning was evaluated in nine patients with ALS with sleep disturbance caused by nocturnal hypoventilation (NIPPV group), and in a comparison group of 10 similar patients without ventilation problems (control group). The NIPPV group then started non-invasive positive pressure ventilation (NIPPV) at night. After about 6 weeks, change in cognitive function was evaluated.
RESULTS Statistically significant improvement in scores on two of the seven cognitive tests was demonstrated in the NIPPV group postventilation, and a trend towards significant improvement was found for two further tests. Scores in the control group did not improve significantly for these four tests, although an improvement was found on one other test.
CONCLUSIONS Nocturnal hypoventilation and sleep disturbance may cause cognitive dysfunction in ALS. These deficits may be partially improved by NIPPV over a 6 week period. This has important implications for investigations of both cognitive dysfunction in non-demented patients with ALS, and the effect of ventilation on quality of life.
