There was no improvement in memory, behaviour or psychometric testing with hyperbaric oxygen therapy in patients with cognitive impairment of the elderly.

Clinical Bottom Line:
1. No evidence of a benefit from hyperbaric oxygen therapy in memory function or psychometric performance in cognitive impairment of the elderly.

Appraised by: Mike Bennett, Dept of Diving and Hyperbaric Medicine, Prince of Wales Hospital
Sydney; Tuesday, 9 March 1999

Clinical Scenario: A 75 year old patient with cognitive impairment related to age.
Three-part Question: In patients with a diagnosis of cognitive impairment of the elderly, does the application of hyperbaric oxygen compared to normobaric oxygen or air, result in any demonstrable improvement in intellectual ability or memory?
Search Terms: Hyperbaric oxygenation, dementia

The Study:
Double-blind randomised controlled trial without intention-to-treat.
Ambulatory patients aged 60 to 85 years who tested to a minimum on an age-related adult intelligence scale vocabulary sub-test (to allow completion of outcome measures) and had a demonstrated deficit of 1 standard deviation or more on 3 out of 5 sub-tests of memory.
Control group (N = 22; 20 analysed): 10% oxygen at 2.3ATA for 90 minutes twice daily for 15 days.
Experimental group (N = 27; 20 analysed): 100% oxygen at 2.5ATA for 90 minutes twice daily for 15 days.

The Evidence:
Non-Event Outcomes Time to outcome Air group HBO group P-value

Recall of faces
(? scale) two weeks 3.29 3.93 NS
Social activity
(0-4 scale) two weeks 1.60 1.92 NS
Mean memory quotient
(0-100) two weeks 78 73 NS

1. Complex outcome measures not presented with clarity.
2. This study also tested normobaric oxygen against placebo in a further two arms (not reported here).
3. There were eight significant differences in 101 F tests across the four groups.
4. There was an 'acclimatisation period' of seven days, during which 38 patients were withdrawn and replaced by others. It is not clear what effect this may have had on the outcome.
5. Authors mention repeated assessment up to 8 weeks but have not given supporting results in this paper.

Expiry date: July 2014
References: 1. Raskin A, Gershon S, Crook T, Sathananthan G, Ferris S. The effects of hyperbaric and normobaric oxygen on cognitive impairment in the elderly. Archives of General Psychiatry 1978; 35:50-56.

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