اثر پیری روی توانایی نامگذاری مقابله ای
|کد مقاله||سال انتشار||مقاله انگلیسی||ترجمه فارسی||تعداد کلمات|
|29972||2003||9 صفحه PDF||سفارش دهید||4158 کلمه|
Publisher : Elsevier - Science Direct (الزویر - ساینس دایرکت)
Journal : Archives of Clinical Neuropsychology, Volume 18, Issue 1, January 2003, Pages 81–89
The change in confrontational naming ability accompanying normal ageing has been widely studied. However, inconsistent findings have been reported. Our study reexamined this issue by adopting both accuracy and response latency as indices for reflecting the effect of normal ageing on confrontational naming. Sixty normal and healthy, Cantonese-speaking Chinese volunteered for this study. Thirty of them belonged to the Young Age Group (YOUNG; M=19.77 years, S.D.=1.5 years) and 30 to the Old Age Group (OLD; M=71.47 years, S.D.=6.51 years). The instrument used was the Chinese Naming Test (CNT) for measuring confrontational naming. The findings indicated that younger people performed much better than older people on the test in terms of accuracy as well as response latency. The observed different performance between the young and old participants could not be explained by their different levels of education. No gender difference in performance on the test was observed. Our findings supported our initial hypothesis that normal ageing does have a negative impact on confrontational naming. The decline in naming ability with ageing may be multifactorial.
The act of naming is important for our understanding of objects in the world (Howes, 1979). The process of naming is immensely complex in its ramifications. To name an object, firstly, we have to detect the stimulus, find a suitable word representing the object, and respond through speaking out the corresponding word. In other words, in addition to the normal visual–perceptual function, successful naming requires effective semantic and phonological processing (Bowles, 1993)—functions that are highly indicated in the frontal and temporal regions for memory, retrieval, and executive functions. There have been numerous models proposed to understand naming (Amrhein, 1995, Bowles, 1993 and Howes, 1979). Goodglass and Wingfield (1997) hypothesized that naming is a two-stage process. The first stage is the quick access of a direct link between the concept of an object and its name. If, for some reason, the link is disturbed, as in the case of tip-of-the-tongue or brain damage, the second stage takes place and a slower associative process takes over. The individual then attempts to self-prompt, using associated concepts or sounds (Tartter, 1998). Naming difficulty, or anomia, is commonly observed in clinical groups with various neurological conditions, e.g., semantic dementia (Papagno & Capitani, 2001), head trauma, e.g., temporal damage (Miceli et al., 2000), and frontal damage (Papagno & Muggia, 1999). Naming difficulty is also a common complaint among the elderly. The decline in naming ability with ageing, if observed, may be multifactorial. One of these factors could be the decline in general cognitive ability accompanying normal ageing. Indeed, according to some researchers (Albert, Heller, & Milberg, 1988; Goulet, Ska, & Kahn, 1994), age decline in picture-naming abilities can be attributed to nonlinear modifications in cognitive function related to selective changes in the brain evolving at differential rates across the life span. There are findings that show various changes happening in old age. La Rue (1992) summarized different changes in the sensory, neurological, musculoskeletal, immunological, cardiovascular, respiratory functions, etc. of the elderly. The neurological changes include reduced brain weight and volume, loss of neurons and changes in dendritic arbors, increased neurofibrillary tangles and neuritic plaques, and other microscopic changes. All these changes may lead to possible intellectual changes, which could in turn affect naming ability. In a PET study of the verbal recognition memory between people in the younger and older age groups, analyses of the performance data yielded evidence of age-related slowing of encoding and retrieval processes, and age-related decline in the accuracy of yes/no recognition. Investigation of regional cerebral blood flow (rCBF) associated with both encoding and retrieval showed bilateral prefrontal activation for older adults, but primarily right frontal activation for young adults. This increased activation could be a sign of inefficient processing as people age (Madden et al., 1999). According to Salthouse (1985), the slowing of the processing rate of mental operation accompanying normal ageing would make many cognitive strategies no longer effective or available for use. Brooks, Friedman, Gibson, and Yesavage (1993) found that although both younger and older adults used mnemonic strategies in remembering proper names, the younger adults recalled more names than did the older subjects. Van Gorp, Satz, Kiersch, and Henry (1986) observed that the mean scores of subjects aged between 59 and 69 years were commensurate with the norms of the Boston Naming Test (BNT) provided (Kaplan, Goodglass, & Weintraub, 1983) for younger individuals, whereas the scores for subjects in their 70s and older were consistently lower. Schacter, Curran, Galluccio, Miberg, and Bates (1996) and Schacter, Osowiecki, Kasniak, Kihlstrom, and Valdiserri (1994) have pointed out that the frontal lobes are critically involved in effortful memory retrieval, which may fail in older subjects because they establish an unfocused representation of the encoding context when searching for the target information. Indeed, decreased performance on measures of frontal lobe functions associated with normal ageing has been widely speculated (Ardila & Rosselli, 1989). Morphological and other neurophysiological changes of the frontal lobe accompanying the normal ageing process may account for this phenomenon. The prefrontal and frontal regions that are essential for supporting our executive processes show large and disproportionate changes with age (Kramer et al., 1999). Shrinkage of cells leading to a general reduction in gross brain volume dominates the prefrontal region above the age of 65. This becomes progressively significant at age 70. This reduction in cell volume might result from the loss of dendritic extensions and a reduction in the number of synapses, i.e., a loss of the connective processes of the neurons. However, below the age of 45, there is little reduction in cell size in any area of the cortex measured (Haug & Eggers, 1991). Neurochemical changes in the frontal region accompanying normal ageing were observed. Work with humans suggests that age-related changes in neurochemistry are observed as both a reduction in the number of receptors (De Keyser, De Backer, Vauquelin, & Ebinger, 1990) and a reduction in the concentration of neurotransmitters (Adolfsson, Gottfries, Roos, & Winblad, 1979). Studies of rCBF indicate a pattern of hypofrontality in older individuals, with greater impact on the prefrontal region (Gur, Gur, Orbist, Skolnick, & Reivich, 1987; Melamed, Lavy, Shlomo, Cooper, & Rinot, 1980). These various changes, together with an active accumulation of greater numbers of the most mature plaques in the prefrontal region (Struble, Price, Cork, & Price, 1985), imply a high toll on the effective and efficient frontal processing accompanying normal ageing. Many studies were conducted to examine the phenomenon of changing naming ability with normal ageing. Positive (Albert et al., 1988, Amrhein, 1995 and Le Dorze & Durocher, 1992; Rosselli, Ardila, & Rosas, 1990) and negative (Beland & Lecours, 1990; Flicker, Ferris, Crook, & Bartus, 1987; Mitchell, 1989) findings were reported. On this issue, Goulet et al. (1994) conducted a systematic review of 25 studies of the picture-naming accuracy of normal ageing individuals and concluded that the inconsistent findings on age-related change in picture naming could be partially explained by methodological discrepancies. A crucial observation is that studies that reported nonsignificant findings used only accuracy in naming as the index of outcome measure. As Goulet et al., 1994 rightly pointed out, most of the research focuses mainly on naming accuracy scores rather than on retrieval latency for words because the former is an easily available and useful indication of picture-naming abilities. Along these same lines, the available norms of most picture-naming tests are based on naming accuracy, but not on word-retrieval latency. This study revisited the issue of the effect of normal ageing on naming and incorporated both accuracy and time latency scores as indices of measurement. The effect of education level on these two indices was controlled and that of gender was studied to provide a clearer picture about the real effect of ageing on naming. It was hypothesized that ageing would have a negative effect on naming. As such, younger people would outperform older people in terms of accuracy and time latency on the naming task.
نتیجه گیری انگلیسی
Correlations between the dependent and independent variables are presented in Table 1. The performance of the YOUNG and the OLD and the results of the ANCOVA procedure are summarized in Table 2. Table 1. Correlations between dependent and independent variables Age Score Latency Education −.892** .709** −.460** Age −.685** .576** Score −.538** Education, years of education; age, age in years; score, accuracy of performance; latency, response. ** P<.01. Table options Table 2. Comparison of performance between the participants of the Young and Old Age Groups YOUNG Mean (S.D.) OLD Mean (S.D.) F df Accuracy scores 111.13 (3.93) 89.07 (15.94) 4.84* 1,55 Latency time (s) 1.89 (0.24) 3.10 (1.29) 4.20* 1,55 * Denotes differences were significant at P<.05 level (two-tailed). Table options 3.1. Accuracy The relationship between accuracy of performance (score) and age (r=−.685, P<.01) and education (r=.709, P<.01) of the participants was moderately strong ( Colton, 1974). The results of the ANCOVA procedure indicated that there is a significant difference in accuracy of performance between the YOUNG and OLD [F(1,55)=4.84, P=.032]. The participants of younger age were more accurate in their responses on the naming test. In contrast, nonsignificant difference in performance was observed between the male and female participants [F(1,55)=3.63, P=.062]. All the interaction effects among the main effects, and between the main effect and covariate, were not statistically significant. Level of education as covariate was not significant [F(1,55)=1.08, P=.302].