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d isp lays s howe d 22 li ne s of le tt e rs co ns is t ing of al toget her 374 le tt e rs co ver ing the who le d isp la y area . Th e se c ond ma in var iab le was the width subte nded by the row 0/ re cognition st i muli . In th e Three Lett er d isplays , the thre e rec og nit ion le tte rs we re cl os e together, s l ight ly spread or wide ly scattered. In bo th No ise d isp lays, these matched let t er s we re s imilarl y d istribu t ed. Wit h vi ewing distances of 28 and 56 in, the three recogn ition width s subtended 1, 3 and 5 degrees , or 2, 6 and 10 deg rees re spect ively. Only the 1 or 2 degree presentation s we re en t ire ly foveal · the other widt hs requ ired pe ripheral and fov e al dis cr iminat ion .' Th e I~tters wer e 0.25 in hi gh and 0 .5 in between centers: they we re of h igh contrast on 8 .5 x 11 in whi te backgrounds . Fcch of the nine arrangements of displays and w idths was prepared in two d ifferent versi ons -w ith the three recognition le tters as N or C. The resu lting 18 cards were randomly mixed w ith an equal number of catch d isplays which had either no matching letters at a ll or only one mat ch ing letter to one side of the centra l letter . Figure 1 shows that the extra unwanted letters or visual noise gave the main effec t . Virtually perfect s cores were made with the Three Letter (No No i s e) at all widths of recognition display. But the additi on of unwanted letters to these identical patterns of three wanted letters gav e a ca tast r ophic reduction in recognition scores. These No i sec 0 n d i t ion s were harmful either as Line or a s Page displays. The worst imp airment was found when the recognition letters ' stretched into the per i p h er a Ire t in a. These Noise displays subtending 3 to 10 degrees aver aged only 10 per cent cor r ec t . Foveal recognition was a lso , however, definitely impair ed by peripheral visual noise , even when the three matching letters were adjacent to each other. Recognition s cores for material in the fovea fell to three-quarters or two-thirds of ac hieveme nt at the Results and Disc uss io n AbstractSs had qui ckly to detect similar ities between two upperca se letters presented peripherally and one other cent ral letter falling on the fovea. Thes e three cha r acters were so legible that this task was very easy when the three letters were flashed on by themselves. But the additi on of extra letters to this display seriously imp aired performance. The periphery of the retina could no longer accuratel y detect a t a glance whether items were similar. Fove al performance was also affected to some extent by extra items in the periphery of the retina. IntroductionPeople usually select the information they want from a general background of unwanted material. Pattern recognition often involves per ipher al matching in the sense that comparisons a r e mad e between one foveal item and many others pl aced in the periphery. Alternatively, similarities and differences a r e noted between two or more entirely peripheral items. This process...

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To test a method of assessing quality of life, 200 primary brain tumor patients in an outpatient clinic answered a 20-minute questionnaire covering ten aspects of quality of life. These results were compared with Karnofsky performance scale (KPS) scores, taking age into account. Among patients with KPS 90-100 (two-thirds of the patients), the KPS alone was difficult to interpret. The questionnaire, with its specific questions related to the key dimension of well-being, provided a more definitive assessment of status. The central importance of well-being was supported by its strong statistical relationships with other dimensions. Particularly, well-being was related to freedom from depression (p < 0.0001), active social life (p < 0.0001), energy (p < 0.01), and fewer symptoms (p < 0.05). The KPS was more useful in differentiating the other one-third of the patients (KPS 50-80) but was highly sensitive to age. KPS scores, therefore, may have been unreliable. Depression, reported by half of the patients, was not predicted by the KPS when age was excluded from the regression analysis but was related to the scores in well-being and socializing. Neither depression, well-being, nor socializing was influenced by age. Thus, the questionnaire directly assessed these central, emotionally based variables, particularly among patients with satisfactory KPS. Such an assessment is especially crucial as a supplement to the KPS in evaluating brain tumor survivors, whose emotional well-being is often severely challenged by treatment after surgical excision.