| Abstract | U općoj populaciji sve je veći udio osoba starije životne dobi koje se suočavaju s promjenama u kognitivnom funkcioniranju. Brojne teorije starenja ističu izvršne funkcije radnog pamćenja kao ključne čimbenike kognitivnog pada. Cilj ovog istraživanja bio je ispitati možemo li osnaživanjem izvršnih funkcija ažuriranja i inhibicije osnažiti radno pamćenje i druge funkcije povezane s radom radnog pamćenja kod starijih odraslih osoba. U predistraživanju je sudjelovalo N = 109 sudionika (M = 69.01, SD = 7.26) temeljem čijeg je uratka u zadacima ažuriranja i inhibicije konstruiran adaptivni treninga ažuriranja (n-unatrag zadatak) i inhibicije (slika-riječ zadatak), kao i odabir mjera glavnog istraživanja. U glavnom istraživanju je sudjelovalo N = 120 sudionika (M = 70.30, SD = 5.84), koji su po slučaju podijeljeni u jednu od četiri grupe: grupa treninga ažuriranja, grupa treninga inhibicije, grupa kombiniranog treninga i grupa komunikacijskih vještina (aktivna kontrolna grupa). Istraživanje je uključivalo 20 sesija treninga i sedam sesija provjere kognitivnog funkcioniranja (predtest, posttest i praćenje 6 mjeseci po završetku treninga). Sudionici su trenirali u vlastitim kućanstvima tri puta tjedno na računalima u trajanju od 25 min po sesiji. Rezultati Bayesove analize varijance za ponovljena mjerenja pokazali su napredak grupe treninga ažuriranja u treniranom zadatku te trend smanjenju broja pogrešaka u slika-riječ zadatku i češćoj provjeri vremena u prospektivnom zadatku pamćenja. Grupa treninga inhibicije napredovala je u treniranom zadatku i n-unatrag zadatku. Kombinirana skupina napredovala je u treniranim zadacima, a potencijalni napredak bio je vidljiv i na mjerama opterećenja kapaciteta pažnje u prospektivnim zadacima. Rezultati pokazuju ograničenost transfera treninga izvršnih funkcija i potencijalno veću učinkovitost kombiniranih treninga. |
| Abstract (english) | Introduction: The share of the population older than 60 is growing more rapidly in comparison to other age groups. Older age is characterized by numerous changes, including changes in cognitive functions. Although some abilities are preserved in older age, a large portion of them decline. Various theories of cognitive aging attempt to explain the mechanism underlying cognitive decline, and most of them relate to the construct of working memory (WM). Recently, executive functions of WM have been increasingly studied as an important component of cognitive decline. One of the ways in which executive functions can be strengthened in older adulthood is through the use of cognitive training. Cognitive training represents structured exercises focusing on different aspects of cognitive functioning. The aim of this study was to examine whether WM, as well as other function related to it, could be enhanced by strengthening the executive functions of updating and inhibition in older adults. Method The study consisted of a preliminary examination and a main experiment. A total of N = 109 older participants (M = 69.01, SD = 7.26) took part in the preliminary study, by performing the updating (N-back; Updating memory task) and inhibition (Picture-word task, Stroop task, Simon task) tasks. Their results have served as a basis in designing adaptive updating and ihibition trainings. Also, they were used to select the measures used in the main study. The main study involved N = 120 older adults (M = 70.30, SD = 5.84) who were randomly selected to one of four groups: an updating training group, an inhibition training group, a combined updating and inhibition training group, and a communication skills practice group (active control group). The study included 27 sessions: 20 training sessions and 7 testing sessions (pretest, posttest and follow-up 6 months after the end of the training). Updating tasks (n-back task, memory updating task), inhibition tasks (picture-word task, Stroop task), WM task (Complex operation span task), fluid reasoning task (Standard Progressive Matrices) and measures of everyday functions (Everyday problem test, Prospective memory event test, Prospective memory time test) were used to test the efficacy of the training. Cognitive examination was conducted by the experimenter and lasted approximately 45 minutes. During the training, participants practiced the task three times per week over a period of seven weeks, by using a computer at their homes, with each session lasting 25 minutes. The training was adaptive, i.e. the difficulty of the task was adapted to the participants' success in the training.
Results: The results of the multilevel modeling showed that the progress during the n-back training for the updating group and the combined group was best described by linear and quadratic functions. Both groups showed faster progress at the beginning of the training, but this initial training rate has slowed down as the training progressed. On the other hand, participants in the inhibition and combined groups showed a linear progression over time during the training. At the same time, the inhibition group had a steeper increase compared to the combined group. To test the transfer effects of the training, a Bayesian repeated measures analysis of variance was performed. The results of the analysis showed that the updating group performed better than the inhibition group and the control group on the trained task at the posttest and follow-up. The updating group significantly reduced the number of errors in the picture-word task, but in the three measurement points the updating group did not differ from the other groups. There was also evidence of more frequent checking of time in prospective memory time task, i.e. the updating group showed a greater tendency to monitor the environment. Updating training did not improve performance on the memory updating task, nor on the measures of other cognitive functions. The trend in the results of the inhibition training indicate lower time cost compared to other groups at the posttest and follow-up. In addition, the inhibition group performed better than the control group at the posttest in the n-back task, but the performance was lower than for the updating group. The inhibition training had no effect on the Stroop task and other cognitive measures. Participants in the combined group made the same progress on the n-back task as the updating group, but their progress on the picture-word task was lower than in the inhibition group. Similar to the updating group, the combined group significantly reduced the number of errors in the picture-word task at follow-up compared to the pretest, but the number of errors did not differ from the remaining groups. There was also evidence of a better performance on the secondary task of prospective memory event and time task. For the remaining measures, there was no evidence of the efficacy of the combined training in improving cognitive performance.
Conclusion: The results of this study support theories that assume that there is no single cognitive function that underlies cognitive decline, but rather that a larger number of functions are responsible for the weakening of cognitive performance in old age. The efficacy of interventions targeting specific processes is limited, and greater efficacy may be achieved through a multimodal approach, i.e. within the training targeting a wider range of cognitive functions. |
