Clinical Endocrinology (1998) 49, 391–396 391  1998 Blackwell Science Ltd Cognitive dysfunction in patients with pituitary tumour who have been treated with transfrontal or transsphenoidal surgery or medication K. A. Peace*, S. M. Orme, S. J. Padayatty, H. P. D. Godfrey² and P. E. Belchetz Department of Endocrinology, The General Infirmary, Leeds, UK, *Department of Psychological Medicine, Otago University, Dunedin, and ² Department of Psychology, Otago University, Dunedin, New Zealand (Received 8 July 1997; returned for revision 11 November 1997; finally revised 6 March 1998; accepted 9 April 1998) Summary OBJECTIVE This study was carried out to examine the neuropsychological status of patients treated for pituitary tumour by transfrontal surgery, trans- sphenoidal surgery or medical treatment only, with or without radiotherapy. DESIGN AND MEASUREMENTS Three groups of 23 patients who had been treated for pituitary tumour were compared with 23 healthy controls on a range of neuropsychological measures. The surgical patients were also subdivided into two groups and compared. The neuropsychological measures were standardized psychological tests designed to assess aspects of attention, memory and executive function. PATIENTS The patients were those who had been treated with transfrontal surgery (n ¼ 23), transsphe- noidal surgery (n ¼ 23) and medication only (n ¼ 23). The groups did not differ with respect to age, education or premorbid ability level as assessed by the National Adult Reading Test. All participants were free of known sources of cognitive impairment other than pituitary tumour. RESULTS Comparison of the four groups revealed that nearly half of the transfrontal, one-third of the transsphenoidal and one-quarter of the non-surgical group had three or more neuropsychological tests scores below the 10th percentile compared to less than 5% of the controls. Impairments in memory and executive function were found in both surgical groups. The non-surgical patients appeared to have problems only on tasks requiring high levels of cog- nitive processing. Differences were found between the two surgical groups with respect to the severity of the cognitive impairment, the transfrontal patients having more severe impairment than the transsphe- noidal. No significant negative effects on cognitive functioning were associated with radiotherapy; how- ever, transfrontal surgery patients who had not been treated with radiotherapy were found to be more impaired than other patients. This was thought to be related to radical surgery. CONCLUSIONS Many patients with treated pituitary tumour suffer significant cognitive impairment. The severity and nature of impairment differs between treatment groups, although the cause of this could not be addressed by this study. Recommendations are made for future research and clinical practice. Although it was widely recognized that tumours of the pituitary gland cause cognitive problems if left untreated, it was not until very recently that systematic investigation demonstrated that patients continue to suffer impairment in cognitive function following treatment of their tumour (Grattan-Smith et al., 1992; Peace et al., 1997). Both the aforementioned studies reported impairments in memory and executive function. Peace et al. (1997) excluded all patients from their study who had any known source of cognitive impairment, other than pituitary tumour, and also demonstrated that the cognitive impairment was not secondary to a mood disorder. It was therefore concluded that the source of cognitive impairment was likely to be multifactorial, but may be associated with treatment variables such as surgery or radiotherapy or due to hormone imbalance resulting from the primary disease or pituitary surgery. The type of surgery used to remove pituitary tumours has changed several times in the past. However, the two most widely used techniques have been the transfrontal route and the transsphenoidal routes. The transfrontal route was the most extensively used until the introduction of intraoperative microscopes and better treatment of post-operative infection made the transsphenoidal route much safer. Transsphenoidal surgery offers faster and easier access to the pituitary gland, allows for better differentiation of the tumour from the gland, Correspondence: Dr K. A. Peace, Department of Psychological Medicine, Otago University, Dunedin, New Zealand. Fax: þ64 3474 7934; e-mail: kathryn.peace@stonebow.otago.ac.nz