[Effects of anesthesia on higher brain functions in the elderly].

Sixty-four patients aged over 60 about to undergo elective surgery of the lower limbs were allocated at random to two groups, one with general anaesthesia, the other with local/regional anaesthesia, in order to compare the effects of these two types of anaesthesia on superior brain functions. The two groups were similar in age, disease, treatment and risk from anaesthesia. Superior brain functions were evaluated by means of a score 24 hours before, then 24 hours and 7 days after the operation. The mean preoperative score was 26.3 +/- 3.4 for the local/regional anaesthesia group and 27.3 +/- 2.6 for the general anaesthesia group, and it remained the same throughout the investigation in both groups. The score decreased to pathological values (less than or equal to 20) in 4 patients from the local/regional anaesthesia group, and this fall was associated with trans- and postoperative incidents (haemorrhage, cardiorespiratory arrest, confusion after receiving pethidine, cardiac decompensation). This study shows that alterations of the superior brain functions are probably related to trans and postoperative incidents rather than to the type of anaesthesia administered.