Lexical retrieval in healthy aging

Semantic processing in older adults is associated with distributed neural activation which varies by association and abstractness of words

The extent to which the neural systems underlying semantic processes degrade with advanced age remains unresolved, which motivated the current study of neural activation on functional magnetic resonance imaging (fMRI) during semantic judgments of associated vs. unassociated, semantic vs. rhyme, and abstract vs. rhyme word pairs. Thirty-eight older adults, 55-85 years of age, performed semantic association decision tasks in a mixed event-related block fMRI paradigm involving binary judgments as to whether word pairs were related (i.e., semantically associated). As hypothesized, significantly greater activation was evident during processing of associated (vs. unassociated) word pairs in cortical areas implicated in semantic processing, including the angular gyrus, temporal cortex, and inferior frontal cortex. Cortical areas showed greater activation to unassociated (vs. associated) word pairs, primarily within a large occipital cluster. Greater activation was evident in cortical areas when response to semantic vs. phonemic word pairs. Contrasting activation during abstract vs. concrete semantic processing revealed areas of co-activation to both semantic classes, and areas that had greater response to either abstract or concrete word pairs. Neural activation across conditions did not vary as a function of greater age, indicating only minimal age-associated perturbation in neural activation during semantic processing. Therefore, the response of the semantic hubs, semantic control, and secondary association areas appear to be largely preserved with advanced age among older adults exhibiting successful cognitive aging. These findings may provide a useful clinical contrast if compared to activation among adults experiencing cognitive decline due Alzheimer's, frontal-temporal dementia, and other neurodegenerative diseases.

How Many Alzheimer-Perusini's Atypical Forms Do We Still Have to Discover?

Alzheimer-Perusini's (AD) disease represents the most spread dementia around the world and constitutes a serious problem for public health. It was first described by the two physicians from whom it took its name. Nowadays, we have extensively expanded our knowledge about this disease. Starting from a merely clinical and histopathologic description, we have now reached better molecular comprehension. For instance, we passed from an old conceptualization of the disease based on plaques and tangles to a more modern vision of mixed proteinopathy in a one-to-one relationship with an alteration of specific glial and neuronal phenotypes. However, no disease-modifying therapies are yet available. It is likely that the only way to find a few "magic bullets" is to deepen this aspect more and more until we are able to draw up specific molecular profiles for single AD cases. This review reports the most recent classifications of AD atypical variants in order to summarize all the clinical evidence using several discrimina (for example, post mortem neurofibrillary tangle density, cerebral atrophy, or FDG-PET studies). The better defined four atypical forms are posterior cortical atrophy (PCA), logopenic variant of primary progressive aphasia (LvPPA), behavioral/dysexecutive variant and AD with corticobasal degeneration (CBS). Moreover, we discuss the usefulness of such classifications before outlining the molecular-genetic aspects focusing on microglial activity or, more generally, immune system control of neuroinflammation and neurodegeneration.

Differences in electroencephalography oscillations between normal aging and mild cognitive impairment during semantic memory retrieval

Semantic memory remains relatively stable with normal cognitive aging and declines in early stages of neurodegenerative disease. We measured electroencephalography (EEG) oscillatory correlates of semantic memory retrieval to examine the effects of normal and pathological aging. Twenty-nine cognitively healthy young adults (YA), 22 cognitively healthy aging adults (HA) and 20 patients with mild cognitive impairment (MCI) completed a semantic memory retrieval task with concurrent EEG recording in which they judged whether two words (features of objects) led to retrieval of an object (retrieval) or not (non-retrieval). Event-related power changes contrasting the two conditions (retrieval vs. non-retrieval) within theta, alpha, low-beta and high-beta EEG frequency bands were examined for normal aging (YA vs. HA) and pathological aging effects (HA vs. MCI). With no behavioural differences between the two normal age groups, we found later theta and alpha event-related power differences between conditions only in YA and a high-beta event-related power difference only in HA. For pathological aging effects, with reduced accuracy in MCI, we found different EEG patterns of early event-related beta power differences between conditions in MCI compared with HA and an event-related low-beta power difference only in HA. Beta oscillations were correlated with behavioural performance only in HA. We conclude that the aging brain relies on faster (beta) oscillations during the semantic memory task. With pathological aging, retrieval accuracy declines and pattern of beta oscillation changes. The findings provide insights about age-related neural mechanisms underlying semantic memory and have implications for early detection of pathological aging.

Priming Sentence Production in Older Adults: Evidence for Preserved Implicit Learning

Purpose

Structural priming- speakers' unconscious tendency to echo previously encountered message-structure mappings - is thought to reflect the processes of implicit language learning that occur throughout the lifespan. Recently, structural priming has also been used as a means to facilitate language re-learning in age-related language disorders such as aphasia. However, little evidence is available on whether structural priming remains effective in healthy aging, limiting clinical translation of the structural priming paradigm. This study examined the impact of aging on the strength and longevity of abstract structural priming and lexical boost effects.

Method

Twenty-four young and 24 older adults participated in a collaborative picture-matching task where the participant and experimenter took turns describing picture cards using transitive and dative sentences. In Experiment 1, a target was elicited immediately following a prime (0-lag), whereas two filler items were embedded between a prime and a target sentence in Experiment 2 (2-lag) to examine longer-term priming effects. In both experiments, the verb was repeated for half of the prime-target pairs to examine lexical boost on structural priming.

Results

At immediate priming, older adults showed both abstract structural priming and lexical boost in transitives and datives, similar to young adults. At longer-term priming, only abstract priming effects were significant in both groups of participants, with no evidence of age-related reduction in priming.

Conclusions

Both lexically-specific and independent mechanisms of structural priming remain resilient in older adults, supporting the view that structural priming reflects life-long language learning. Further, the findings provide empirical basis for applying structural priming to elderly clinical populations.

Lexical and Acoustic Speech Features Relating to Alzheimer Disease Pathology

BACKGROUND AND OBJECTIVES

We compared digital speech and language features of patients with amnestic Alzheimer disease (aAD) or logopenic variant primary progressive aphasia (lvPPA) in a biologically confirmed cohort and related these features to neuropsychiatric test scores and CSF analytes.

METHODS

We included patients with aAD or lvPPA with CSF (phosphorylated tau ([p-tau]/β-amyloid [Aβ] ≥0.09, and total tau/Aβ ≥0.34) or autopsy confirmation of AD pathology and age-matched healthy controls (HC) recruited at the Frontotemporal Degeneration Center of the University of Pennsylvania for a cross-sectional study. We extracted speech and language variables with automated lexical and acoustic pipelines from participants' oral picture descriptions. We compared the groups and correlated distinct features with clinical ratings and CSF p-tau levels.

RESULTS

We examined patients with aAD (n = 44; age 62 ± 8 years; 24 women; Mini-Mental State Examination [MMSE] score 21.1 ± 4.8) or lvPPA (n = 21; age 64.1 ± 8.2 years; 11 women; MMSE score 23.0 ± 4.2) and HC (n = 28; age 65.9 ± 5.9 years, 15 women; MMSE score 29 ± 1). Patients with lvPPA produced fewer verbs (10.5 ± 2.3; p = 0.001) and adjectives (2.7 ± 1.3, p = 0.019) and more fillers (7.4 ± 3.9; p = 0.022) with lower lexical diversity (0.84 ± 0.1; p = 0.05) and higher pause rate (54.2 ± 19.2; p = 0.015) than individuals with aAD (verbs 12.5 ± 2; adjectives 3.8 ± 2; fillers 4.9 ± 4.5; lexical diversity 0.87 ± 0.1; pause rate 45.3 ± 12.8). Both groups showed some shared language impairments compared with HC. Word frequency (MMSE score: β = -1.6, p = 0.009; Boston Naming Test [BNT] score: β = -4.36, p < 0.001), adverbs (MMSE score: β = -1.9, p = 0.003; BNT score: β = -2.41, p = 0.041), pause rate (MMSE score: β = -1.21, p = 0.041; BNT score: β = -2.09, p = 0.041), and word length (MMSE score: β = 1.75, p = 0.001; BNT score: β = 2.94, p = 0.003) were significantly correlated with both MMSE and BNT scores, but other measures were not correlated with MMSE and/or BNT score. Prepositions (r = -0.36, p = 0.019), nouns (r = -0.31, p = 0.047), speech segment duration (r = -0.33, p = 0.032), word frequency (r = 0.33, p = 0.036), and pause rate (r = 0.34, p = 0.026) were correlated with patients' CSF p-tau levels.

DISCUSSION

Our measures captured language and speech differences between the 2 phenotypes that traditional language-based clinical assessments failed to identify. This work demonstrates the potential of natural speech in reflecting underlying variants with AD pathology.

Development and Psychometric Evaluation of Alternate Short Forms of the Action Naming Test

OBJECTIVE

The action naming test (ANT) is a confrontation naming task used to assess the ability to name action words. This study aimed to create two short forms of the ANT and assess their equivalence, reliability, and comparability to the long form.

METHODS

In total, 100 healthy adults (31 females and 69 males), aged 34-89 years (M = 64 and SD = 10.4) were recruited. Short forms were developed using a split-half procedure.

RESULTS

No significant differences were observed between short forms on mean performance and distribution of scores for correct spontaneous responses, responses after semantic cue and total correct responses after cueing, but a higher number of accurate responses were prompted after phonemic cueing for Form A. Significant strong correlations between short forms and with the full form were encountered, although a weak correlation was found between short forms on performance after semantic cueing. IQ and age were significant predictors of action word retrieval. Whereas IQ also predicted post-cueing performance in all ANT forms, age predicted performance only for Form B.

CONCLUSION

The two ANT short forms are equivalent when considering total spontaneous responses and total correct responses after cueing, but semantic and phonemic cues evoked different responses on the two forms. The two short forms were also affected differently by demographics. When the psychometric equivalence of Forms A and B was examined, the strict conditions for parallel forms were not met for all performance indices. Therefore, these newly developed short versions should be considered as alternate forms.

Differential Associations of White Matter Brain Age With Language-Related Mechanisms in Word-Finding Ability Across the Adult Lifespan

Research on cognitive aging has established that word-finding ability declines progressively in late adulthood, whereas semantic mechanism in the language system is relatively stable. The aim of the present study was to investigate the associations of word-finding ability and language-related components with brain aging status, which was quantified by using the brain age paradigm. A total of 616 healthy participants aged 18–88 years from the Cambridge Centre for Ageing and Neuroscience databank were recruited. The picture-naming task was used to test the participants’ language-related word retrieval ability through word-finding and word-generation processes. The naming response time (RT) and accuracy were measured under a baseline condition and two priming conditions, namely phonological and semantic priming. To estimate brain age, we established a brain age prediction model based on white matter (WM) features and estimated the modality-specific predicted age difference (PAD). Mass partial correlation analyses were performed to test the associations of WM-PAD with the cognitive performance measures under the baseline and two priming conditions. We observed that the domain-specific language WM-PAD and domain-general WM-PAD were significantly correlated with general word-finding ability. The phonological mechanism, not the semantic mechanism, in word-finding ability was significantly correlated with the domain-specific WM-PAD. In contrast, all behavioral measures of the conditions in the picture priming task were significantly associated with chronological age. The results suggest that chronological aging and WM aging have differential effects on language-related word retrieval functions, and support that cognitive alterations in word-finding functions involve not only the domain-specific processing within the frontotemporal language network but also the domain-general processing of executive functions in the fronto-parieto-occipital (or multi-demand) network. The findings further indicate that the phonological aspect of word retrieval ability declines as cerebral WM ages, whereas the semantic aspect is relatively resilient or unrelated to WM aging.

Aging affects steaks more than knives: Evidence that the processing of words related to motor skills is relatively spared in aging

Lexical-processing declines are a hallmark of aging. However, the extent of these declines may vary as a function of different factors. Motivated by findings from neurodegenerative diseases and healthy aging, we tested whether 'motor-relatedness' (the degree to which words are associated with particular human body movements) might moderate such declines. We investigated this question by examining data from three experiments. The experiments were carried out in different languages (Dutch, German, English) using different tasks (lexical decision, picture naming), and probed verbs and nouns, in all cases controlling for potentially confounding variables (e.g., frequency, age-of-acquisition, imageability). Whereas 'non-motor words' (e.g., steak) showed age-related performance decreases in all three experiments, 'motor words' (e.g., knife) yielded either smaller decreases (in one experiment) or no decreases (in two experiments). The findings suggest that motor-relatedness can attenuate or even prevent age-related lexical declines, perhaps due to the relative sparing of neural circuitry underlying such words.

Preliminary assessment of connected speech and language as marker for cognitive change in late middle-aged Black/African American adults at risk for Alzheimer's disease

Background

Connected speech-language (CSL) has been a promising measure of assessing cognitive decline in populations at-risk for Alzheimer's disease and related dementias (ADRD) populations. A common way to obtain CSL is through using picture description tasks such as the most frequently used image Cookie Theft (CT). However, questions have been raised about using CT for diverse communities. Little is known about the CSL produced in response to this task in Black/African American (BAA) adults aged 48-74.

Goals

The present study's goals were to characterize CSL in BAA adults by sex and APOE-ε4 status from Milwaukee in the Wisconsin Registry for Alzheimer's Prevention (WRAP) study when presented with the CT picture description task and to identify differences in CSL output between BAAs and non-Hispanic Whites (NHW).

Methods and Procedures

We collected CSL samples from the CT picture from 48 BAA participants and 30 NHW participants from the WRAP participants in Milwaukee, WI group. CSL was analyzed using chi-square tests, T-tests, and ANCOVA. Linear mixed effect regression models were used to determine the association between cognitive status and longitudinal CSL in BAA participants with more than 1 timepoint.

Outcomes and Results

Declines in CSL of BAA participants were associated with subtle declines in cognition. Among BAA participants, we found no significant differences in speech measures in terms of sex and APOE-ε4 status. Our results showed no significant differences in speech measures between BAA and NHW groups.

Conclusions

CSL analysis provides an inexpensive way to evaluate preclinical changes in cognitive status that may not be as affected by other factors, such as ethnocultural background. Future studies with larger sample sizes and participants from other geographic locations can clarify these findings.

Lexical and Acoustic Characteristics of Young and Older Healthy Adults

Purpose This study examines the effect of age on language use with an automated analysis of digitized speech obtained from semistructured, narrative speech samples. Method We examined the Cookie Theft picture descriptions produced by 37 older and 76 young healthy participants. Using modern natural language processing and automatic speech recognition tools, we automatically annotated part-of-speech categories of all tokens, calculated the number of tense-inflected verbs, mean length of clause, and vocabulary diversity, and we rated nouns and verbs for five lexical features: word frequency, familiarity, concreteness, age of acquisition, and semantic ambiguity. We also segmented the speech signals into speech and silence and calculated acoustic features, such as total speech time, mean speech and pause segment durations, and pitch values. Results Older speakers produced significantly more fillers, pronouns, and verbs and fewer conjunctions, determiners, nouns, and prepositions than young participants. Older speakers' nouns and verbs were more familiar, more frequent (verbs only), and less ambiguous compared to those of young speakers. Older speakers produced shorter clauses with a lower vocabulary diversity than young participants. They also produced shorter speech segments and longer pauses with increased total speech time and total number of words. Lastly, we observed an interaction of age and sex in pitch ranges. Conclusions Our results suggest that older speakers' lexical content is less diverse, and these speakers produce shorter clauses than young participants in monologic, narrative speech. Our findings show that lexical and acoustic characteristics of semistructured speech samples can be examined with automated methods.

Fast Periodic Visual Stimulation indexes preserved semantic memory in healthy ageing

Behavioural studies investigating the preservation of semantic memory in healthy ageing have reported mixed findings. One suggested reason for this discrepancy is that the processes underpinning lexical access to semantic knowledge may be sensitive to ageing. It is therefore necessary to assess semantic memory utilising tasks that are not explicitly linguistic. In this study, a fast periodic visual stimulation (FPVS) paradigm coupled with EEG was used to assess the ability of younger and older adults to automatically distinguish between images by their semantic category. Participants were presented with a 6 Hz stream of images drawn from one semantic category except every fifth image (occurring at a rate of 1.2 Hz) which was drawn from an alternate semantic category. For both younger and older adults, results demonstrate successful and comparable semantic categorisation. This was detectable at the individual level for 71% and 72% of older and younger adults, respectively. Given the rapid presentation rate and absence of explicit instruction to categorise images, the task is unlikely to utilise linguistic strategies and suggests the maintenance of semantic memory in healthy ageing. Moreover, this study utilised mobile EEG equipment and short presentation times that would be suitable for practical application outside a research setting.

A new revised Graded Naming Test and new normative data including older adults (80-97 years)

The Graded Naming Test (GNT) is commonly used in clinical and research settings to assess nominal functions. However, normative data for the GNT is over 20 years old and norms for the older adult population are rather limited. Hence, confounding factors such as generational familiarity due to cultural changes need to be considered when applying the currently available norms. Moreover, normative data for the older population (80-97) are virtually absent. Such factors can be powerful confounds that can lead to incorrect interpretation of test scores. We gathered data for the GNT from 326 healthy controls aged between 18 and 97 years. Surprisingly, we found no decline in performance for older adults, even for the cohort aged 80-97 years (N = 40). In contrast, the youngest cohort (aged 18-29 years) performed unexpectedly below the whole sample mean. An item-by-item analysis revealed that five test items were unfamiliar to the youngest age cohort. To account for this generational familiarity effect, we created a revised 25-item GNT. The performance of the youngest cohort on the 25-item GNT was no longer below the whole sample mean. The performance of the oldest cohort (80-97 years old) on the revised GNT was characterized by a significant decline in performance for the oldest cohort with an average NART IQ. By contrast, those with a NART IQ above the average range did not show a decline. This suggests that factors such cognitive reserve arrested the decline in performance in the oldest age cohort with higher premorbid IQ.

The Multilingual Naming Test (MINT) as a Measure of Picture Naming Ability in Alzheimer's Disease

OBJECTIVE

The present study investigated the ability of the Multilingual Naming Test (MINT), a picture naming test recently added to the National Alzheimer's Coordinating Center's (NACC) Uniform Data Set neuropsychological test battery, to detect naming impairment (i.e., dysnomia) across stages of Alzheimer's disease (AD).

METHOD

Data from the initial administration of the MINT were obtained on NACC participants who were cognitively normal (N = 3,981) or diagnosed with mild cognitive impairment (N = 852) or dementia (N = 1,148) with presumed etiology of AD. Dementia severity was rated using the Clinical Dementia Rating (CDR) scale.

RESULTS

Cross-sectional multiple regression analyses revealed significant effects of diagnostic group, sex, education, age, and race on naming scores. Planned comparisons collapsing across age and education groups revealed significant group differences in naming scores across levels of dementia severity. ROC curve analyses showed good diagnostic accuracy of MINT scores for distinguishing cognitively normal controls from AD dementia, but not from MCI. Within the cognitively normal group, there was a robust interaction between age and education such that naming scores exhibited the most precipitous drop across age groups for the least educated participants. Additionally, education effects were stronger in African-Americans than in Whites (a race-by-education interaction), and race effects were stronger in older than in younger age groups (a race-by-age interaction).

CONCLUSIONS

The MINT successfully detects naming deficits at different levels of cognitive impairment in patients with MCI or AD dementia, but comparison to age, sex, race, and education-corrected norms to determine impairment is essential.

The Role of Executive Functions in Object- and Action-Naming among Older Adults

Background/Study Context: Lexical retrieval abilities and executive function skills decline with age. The extent to which these processes might be interdependent remains unknown. The aim of the current study was to examine whether individual differences in three executive functions (shifting, fluency, and inhibition) predicted naming performance in older adults. Methods: The sample included 264 adults aged 55-84. Six measures of executive functions were combined to make three executive function composites scores. Lexical retrieval performance was measured by accuracy and response time on two tasks: object naming and action naming. We conducted a series of multiple regressions to test whether executive function performance predicts naming abilities in older adults. Results: We found that different executive functions predicted naming speed and accuracy. Shifting predicted naming accuracy for both object and action naming while fluency predicted response times on both tests as well as object naming accuracy, after controlling for education, gender, age, working memory span, and speed of processing in all regressions. Interestingly, inhibition did not contribute to naming accuracy or response times on either task. Conclusion: The findings support the notion that preservation of some executive functions contributes to successful naming in older adults and that different executive functions are associated with naming speed and accuracy.

Language planning and pauses in story retell: Evidence from aging and Parkinson's disease

We examined if and how pauses during connected speech reflect cognitive processes underlying language formulation in typical aging and Parkinson's disease (PD), beyond respiratory and motor-speech mechanisms. The frequency of silent pauses was measured (a) in relation to different linguistic (independent clausal, subordinate clausal, phrasal, and atypical) boundaries and (b) proficiency measures of language production in young adults, older adults, and individuals with PD. At the group level, aging, but not PD, resulted in increased pausing at atypical linguistic locations. However, in both aging and PD, individuals' reduced production of syntactically complex sentences was associated with more frequent pausing at various typical prosodic (clausal or phrasal) boundaries. Frequency of pauses was not associated with individual performance in grammaticality of sentences and lexical-semantic production. Overall, the present study demonstrated that production of pauses during connected speech reflects cognitive processes underlying language production beyond respiratory-physiological processes of communication. Assessing production of pauses in connected speech may augment, but does not replace, assessment of language production in clinical practice.

Aging deficits in naturalistic speech production and monitoring revealed through reading aloud

The current study investigated how aging affects production and self-correction of errors in connected speech elicited via a read aloud task. Thirty-five cognitively healthy older and 56 younger participants read aloud 6 paragraphs in each of three conditions increasing in difficulty: (a) normal, (b) nouns-swapped (in which nouns were shuffled across pairs of sentences in each paragraph), and (c) exchange (in which adjacent words in every two sentences were reversed in order). Reading times and errors increased with task difficulty, but self-correction rates were lowest in the nouns-swapped condition. Older participants read aloud more slowly, and after controlling for aging-related advantages in vocabulary knowledge, produced more speech errors (especially in the normal condition), and self-corrected errors less often than younger participants. Exploratory analysis of error types revealed that aging increased the rate of function word substitution errors (saying the instead of a), whereas younger participants omitted content words more often than did older participants. This pattern of aging deficits reveals powerful effects of vocabulary knowledge on speech production and suggests aging speakers can compensate for aging-related decline in control over speech production with their higher vocabulary knowledge and careful attention to speech planning in more difficult speaking conditions. These results suggest a model of speech production in which planning of speech is relatively automatic, whereas monitoring and self-correction are more attention-demanding, in turn leaving speech production relatively intact in aging. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Healthy Aging and Dementia: Two Roads Diverging in Midlife?

Dementia, particularly Alzheimer’s disease (AD), is a growing pandemic that presents profound challenges to healthcare systems, families, and societies throughout the world. By 2050, the number of people living with dementia worldwide could almost triple, from 47 to 132 million, with associated costs rising to $3 trillion. To reduce the future incidence of dementia, there is an immediate need for interventions that target the disease process from its earliest stages. Research programs are increasingly starting to focus on midlife as a critical period for the beginning of AD-related pathology, yet the indicators of the incipient disease process in asymptomatic individuals remain poorly understood. We address this important knowledge gap by examining evidence for cognitive and structural brain changes that may differentiate, from midlife, healthy aging and pathological AD-related processes. This review crystallizes emerging trends for divergence between the two and highlights current limitations and opportunities for future research in this area.

The Effect of Stimulus Valence on Lexical Retrieval in Younger and Older Adults

PURPOSE

Although there is evidence that emotional valence of stimuli impacts lexical processes, there is limited work investigating its specific impact on lexical retrieval. The current study aimed to determine the degree to which emotional valence of pictured stimuli impacts naming latencies in healthy younger and older adults.

METHOD

Eighteen healthy younger adults and 18 healthy older adults named positive, negative, and neutral images, and reaction time was measured.

RESULTS

Reaction times for positive and negative images were significantly longer than reaction times for neutral images. Reaction times for positive and negative images were not significantly different. Whereas older adults demonstrated significantly longer naming latencies overall than younger adults, the discrepancy in latency with age was far greater when naming emotional pictures.

CONCLUSIONS

Emotional arousal of pictures appears to impact naming latency in younger and older adults. We hypothesize that the increase in naming latency for emotional stimuli is the result of a necessary disengagement of attentional resources from the emotional images prior to completion of the naming task. We propose that this process may affect older adults disproportionately due to a decline in attentional resources as part of normal aging, combined with a greater attentional preference for emotional stimuli.

Effects of Education on Differential Item Functioning on the 15-Item Modified Korean Version of the Boston Naming Test

OBJECTIVE

Education is expected to have an effect on differential item functioning (DIF) on the 15-item Modified Boston Naming Test in the Korean version of the Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet (BNT-KC). However, no study has examined DIF in the BNT-KC.

METHODS

We used the item response theory to investigate the impact of education on the DIF in the BNT-KC among elderly individuals with or without dementia (n=720). A two-parameter item response model was used to determine the difficulty and discrimination parameters of each item. The Benjamini-Hochberg procedure was used to address the risk of Type I errors on multiple testing.

RESULTS

Four items, "mermaid," "acorn," "compass," and "pomegranate" continued to demonstrate DIF after controlling for multiple comparisons. Those with low education levels were more likely to error on "mermaid" and "compass," while those with high education levels were more likely to error on "acorn" and "pomegranate." "Hand" and "red pepper" were too easily identified to be used for detecting dementia patients. "Monk's hat" and "pomegranate" were less discriminating than other items, limiting their usefulness in clinical setting.

CONCLUSION

These findings may provide useful information for the development of a revised version of the BNT-KC to help clinicians make diagnostic decisions more accurately.

Usefulness of investigating error profiles in diagnosis of naming impairments

BACKGROUND

Word-retrieval difficulties are commonly experienced by people with aphasia (PwA) and also by typically ageing persons. Differentiation between true naming impairments and naming difficulties found in healthy persons may, therefore, be challenging.

AIMS

To investigate the extent to which the Maltese adaptation of the Boston Naming Test (BNT) can identify people with lexical retrieval difficulties and to differentiate them from people with unimpaired word finding.

METHODS & PROCEDURES

Naming performance of a group of PwA was compared with the performance of a control group. Performance on the Maltese adaptation of the BNT was investigated in terms of scores, range of scores and error profiles of the two groups.

OUTCOMES & RESULTS

All PwA scored below the mean score of the controls, indicating that persons who scored above the mean score may be considered as unimpaired. However, a number of the controls obtained very low scores that overlapped with the scores obtained by the PwA. This indicated that scores alone cannot be used to differentiate between impaired and unimpaired people. Some types of errors were only produced by people with impaired naming, and did not appear at all in error profiles of unimpaired individuals.

CONCLUSIONS & IMPLICATIONS

Mild-moderate anomic impairments may be missed if naming impairment is assessed and diagnosed using a cut-off score. In order to differentiate between people with impaired and unimpaired naming, it is necessary to look at error profiles, apart from the number of errors, as the presence of atypical errors may be an important indicator of naming impairments.

A Maltese adaptation of the Boston Naming Test: A shortened version

The Boston Naming Test (BNT) is the most widely used naming test worldwide in research and clinical settings. This study aimed to develop a method for adapting the BNT to suit different linguistic and cultural characteristics using the example of Maltese in a bilingual context. In addition, it investigated the effects in Malta of age and level of education on naming performance. The words of the BNT were first translated into Maltese. The test was then piloted to establish target and alternative responses. Naming performance data were later collected from individuals of different ages and levels of education. Only 38 BNT items had at least 70% name agreement. Main effects of age and education were found. A Maltese adaptation was proposed using 38 items and lenient scoring. Similar procedures may be used in other bilingual populations. The study suggests that normative data should be stratified according to age and education.

When a funnel becomes a martini glass: Adolescent performance on the Boston Naming Test

The Boston Naming Test (BNT), a component of the Boston Diagnostic Aphasia Examination, is often used by neuropsychologists to assess confrontation naming. Research indicates that performance on the BNT is impacted by a variety of factors including age, gender, measured intelligence, educational attainment, vocabulary knowledge, level of acculturation, and ethnicity. Extant normative data are available for adults and for younger children; however, descriptive data are lacking for neurologically intact adolescents. The current study obtained normative data for the BNT, second edition in 15- to 18-year-old adolescents. The sample included 200 participants (100 male, 100 female) who were screened to exclude individuals with neurologic, psychiatric, or academic difficulties. There were no statistically significant differences in BNT scores based on gender, age, or grade. Normative means and standard deviations, collapsed across age and gender, are provided. The relationship of the current data to existing child and adult norms, as well as the clinical utility of examining individual item responses for the BNT in this sample are addressed.

The timing of cognitive plasticity in physiological aging: a tDCS study of naming

This study aimed to explore the effects of transcranial direct current stimulation (tDCS) on physiologically aging adults performing a naming task. tDCS is a method that modulates human cortical excitability. Neuroplasticity is considered to have its foundation in cortical excitability as a property that adjusts the connection strength between neurons in the brain. Language efficiency, as all functions, relies on integration of information (i.e., effectiveness of connectivity) through neurons in the brain. So the use of tDCS, to modulate cortical excitability, can help to define the state of cognitive plasticity in the aging brain. Based on Hebb's rule, an increase in synaptic efficacy does not rely only on the increase of excitability but also on the timing of activation. Therefore, a key issue in this study is the timing of tDCS application in relation to a task: When to deliver tDCS to induce modulatory effects on task execution to facilitate naming. Anodal tDCS was applied to the left dorsolateral prefrontal cortex of older and young adults before and during a naming task. In older adults, tDCS improved naming performance and decreased the verbal reaction times only if it was applied during the task execution, whereas in young subjects both stimulation conditions improved naming performance. These findings highlight that in healthy aging adults, the cerebral network dedicated to lexical retrieval processing may be facilitated only if stimulation is applied to an "active" neural network. We hypothesize that this change is due to the neuronal synaptic changes, in the aging brain, which reduce the window of when cortical excitability can facilitate synaptic efficacy and therefore plasticity.

Brain and language: evidence for neural multifunctionality

This review paper presents converging evidence from studies of brain damage and longitudinal studies of language in aging which supports the following thesis: the neural basis of language can best be understood by the concept of neural multifunctionality. In this paper the term "neural multifunctionality" refers to incorporation of nonlinguistic functions into language models of the intact brain, reflecting a multifunctional perspective whereby a constant and dynamic interaction exists among neural networks subserving cognitive, affective, and praxic functions with neural networks specialized for lexical retrieval, sentence comprehension, and discourse processing, giving rise to language as we know it. By way of example, we consider effects of executive system functions on aspects of semantic processing among persons with and without aphasia, as well as the interaction of executive and language functions among older adults. We conclude by indicating how this multifunctional view of brain-language relations extends to the realm of language recovery from aphasia, where evidence of the influence of nonlinguistic factors on the reshaping of neural circuitry for aphasia rehabilitation is clearly emerging.

Superior longitudinal fasciculus and language functioning in healthy aging

Structural deterioration of brain tissue in older adults is thought to be responsible for the majority of age-related cognitive decline. Disruption of widespread cortical networks due to a loss of axonal integrity may also play an important role. Research examining correlations between structural change and functional decline has focused heavily on working memory, processing speed, and executive processes while other aspects of cognition, such as language functioning, have received less attention. The current study aimed to determine whether age-related changes in the superior longitudinal fasciculus (SLF), are responsible for the deterioration in language functioning associated with age. Subjects included 112 right-handed volunteers (ages 19-76). For each subject, the SLF of the left hemisphere was reconstructed from diffusion tensor images (DTI). Mean fractional anisotropy (FA) values were extracted from parietal (SLFp) and temporal (SLFt) bundles. Language functioning was measured using the Peabody Picture Vocabulary Test (PPVT), Boston Naming Test (BNT), Controlled Oral Word Association Test (COWAT), and Semantic Fluency Test (SFT). Regression analyses revealed that males and females showed a different pattern of decline in FA across adulthood. For males, greater SLFt FA was significantly associated with increased COWAT performance, and there was a positive relationship between both age and SLFp FA with BNT scores. In females, greater SLFp FA was related to lower COWAT performance. Taken together, the results suggest that white matter integrity of the SLF follows a different pattern of decline in adulthood for males and females, and this decline differentially affects language functioning.

Grey matter correlates of three language tests in non-demented older adults

Language has been extensively investigated by functional neuroimaging studies. However, only a limited number of structural neuroimaging studies have examined the relationship between language performance and brain structure in healthy adults, and the number is even less in older adults. The present study sought to investigate correlations between grey matter volumes and three standardized language tests in late life. The participants were 344 non-demented, community-dwelling adults aged 70-90 years, who were drawn from the population-based Sydney Memory and Ageing Study. The three language tests included the Controlled Oral Word Association Task (COWAT), Category Fluency (CF), and Boston Naming Test (BNT). Correlation analyses between voxel-wise GM volumes and language tests showed distinctive GM correlation patterns for each language test. The GM correlates were located in the right frontal and left temporal lobes for COWAT, in the left frontal and temporal lobes for CF, and in bilateral temporal lobes for BNT. Our findings largely corresponded to the neural substrates of language tasks revealed in fMRI studies, and we also observed a less hemispheric asymmetry in the GM correlates of the language tests. Furthermore, we divided the participants into two age groups (70-79 and 80-90 years old), and then examined the correlations between structural laterality indices and language performance for each group. A trend toward significant difference in the correlations was found between the two age groups, with stronger correlations in the group of 70-79 years old than those in the group of 80-90 years old. This difference might suggest a further decline of language lateralization in different stages of late life.

Age-related changes of gene expression in the neocortex: preliminary data on RNA-Seq of the transcriptome in three functionally distinct cortical areas

The study of gene expression (i.e., the study of the transcriptome) in different cells and tissues allows us to understand the molecular mechanisms of their differentiation, development and functioning. In this article, we describe some studies of gene-expression profiling for the purposes of understanding developmental (age-related) changes in the brain using different technologies (e.g., DNA-Microarray) and the new and increasingly popular RNA-Seq. We focus on advancements in studies of gene expression in the human brain, which have provided data on the structure and age-related variability of the transcriptome in the brain. We present data on RNA-Seq of the transcriptome in three distinct areas of the neocortex from different ages: mature and elderly individuals. We report that most age-related transcriptional changes affect cellular signaling systems, and, as a result, the transmission of nerve impulses. In general, the results demonstrate the high potential of RNA-Seq for the study of distinctive features of gene expression among cortical areas and the changes in expression through normal and atypical development of the central nervous system.

Changes in naming and semantic abilities with aging from 50 to 90 years

The aim of this study was to determine whether naming difficulties arise in individuals as young as their 50s. Participants of 25-35, 50-59, 60-69, and above 70 years of age were given a picture naming task. To uncover subtle naming difficulties, latencies were analyzed in addition to accuracy. To control whether the expected slower naming latencies could be due to a general slowing affecting all cognitive tasks, participants were also given an odd/even judgment task to assess cognitive processing speed. The results confirmed that participants in their 50s presented decline in naming performance, reflected by an increase in naming latencies, whereas adults in their 60s and their 70s showed both a decrease in accuracy and an increase in latency. Moreover, the increase in naming latencies remained significant even after controlling for odd/even judgment latencies, suggesting a degradation specific to the picture naming task. We assumed that these slower latencies may result from a language-specific impairment. As a further test for language-specific degradation, participants' semantic capacities were also assessed with a synonym judgment task and the Pyramids and Palm Trees test. The above-70 group showed semantic degradation. The contributions of multiple factors to naming difficulties in aging are discussed.

Determiner primes as facilitators of lexical retrieval in English

Gender priming studies have demonstrated facilitation of noun production following pre-activation of a target noun's grammatical gender. Findings provide support for models in which syntactic information relating to words is stored within the lexicon and activated during lexical retrieval. Priming effects are observed in the context of determiner plus noun phrase production. Few studies demonstrate gender priming effects in bare noun production (i.e., nouns in isolation). We investigated the effects of English determiner primes on bare mass and count noun production. In two experiments, participants named pictures after exposure to primes involving congruent, incongruent and neutral determiners. Facilitation of noun production by congruent and neutral determiner primes was found in both experiments. The results suggest that noun phrase syntax is activated in lexical retrieval, even when not explicitly required for production. Post hoc analysis of the relative frequency of congruent and incongruent prime-target pairs provides support for a frequency-based interpretation of the data.

Anatomical correlates for category-specific naming of objects and actions: a brain stimulation mapping study

The production of object and action words can be dissociated in aphasics, yet their anatomical correlates have been difficult to distinguish in functional imaging studies. To investigate the extent to which the cortical neural networks underlying object- and action-naming processing overlap, we performed electrostimulation mapping (ESM), which is a neurosurgical mapping technique routinely used to examine language function during brain-tumor resections. Forty-one right-handed patients who had surgery for a brain tumor were asked to perform overt naming of object and action pictures under stimulation. Overall, 73 out of the 633 stimulated cortical sites (11.5%) were associated with stimulation-induced language interferences. These interference sites were very much localized (<1 cm(2) ), and showed substantial variability across individuals in their exact localization. Stimulation interfered with both object and action naming over 44 sites, whereas it specifically interfered with object naming over 19 sites and with action naming over 10 sites. Specific object-naming sites were mainly identified in Broca's area (Brodmann area 44/45) and the temporal cortex, whereas action-naming specific sites were mainly identified in the posterior midfrontal gyrus (Brodmann area 6/9) and Broca's area (P = 0.003 by the Fisher's exact test). The anatomical loci we emphasized are in line with a cortical distinction between objects and actions based on conceptual/semantic features, so the prefrontal/premotor cortex would preferentially support sensorimotor contingencies associated with actions, whereas the temporal cortex would preferentially underpin (functional) properties of objects.

Naming ability changes in physiological and pathological aging

Over the last two decades, age-related anatomical and functional brain changes have been characterized by evidence acquired primarily by means of non-invasive functional neuroimaging. These functional changes are believed to favor positive reorganization driven by adaptations to system changes as compensation for cognitive decline. These functional modifications have been linked to residual brain plasticity mechanisms, suggesting that all areas of the brain remain plastic during physiological and pathological aging. A technique that can be used to investigate changes in physiological and pathological aging is non-invasive brain stimulation (NIBS). The present paper reviews studies that have applied NIBS in younger and older adults and in patients with dementia to track changes in the cerebral areas involved in a language task (naming). The results of this research suggest that the left frontal and temporal areas are crucial during naming. Moreover, it is suggested that in older adults and patients with dementia, the right prefrontal cortex is also engaged during naming tasks, and naming performance correlates with age and/or the degree of the pathological process. Potential theories underlying the bilateral involvement of the prefrontal cortex are discussed, and the relationship between the bilateral engagement of the prefrontal cortex and the age or degree of pathology is explored.

Item-level psychometrics and predictors of performance for Spanish/English bilingual speakers on an object and action naming battery

PURPOSE

There is a pressing need for psychometrically sound naming materials for Spanish/English bilingual adults. To address this need, in this study the authors examined the psychometric properties of An Object and Action Naming Battery (An O&A Battery; Druks & Masterson, 2000) in bilingual speakers.

METHOD

Ninety-one Spanish/English bilinguals named O&A Battery items in English and Spanish. Responses underwent a Rasch analysis. Using correlation and regression analyses, the authors evaluated the effect of psycholinguistic (e.g., imageability) and participant (e.g., proficiency ratings) variables on accuracy.

RESULTS

Rasch analysis determined unidimensionality across English and Spanish nouns and verbs and robust item-level psychometric properties, evidence for content validity. Few items did not fit the model, there were no ceiling or floor effects after uninformative and misfit items were removed, and items reflected a range of difficulty. Reliability coefficients were high, and the number of statistically different ability levels provided indices of sensitivity. Regression analyses revealed significant correlations between psycholinguistic variables and accuracy, providing preliminary construct validity. The participant variables that contributed most to accuracy were proficiency ratings and time of language use.

CONCLUSIONS

Results suggest adequate content and construct validity of O&A items retained in the analysis for Spanish/English bilingual adults and support future efforts to evaluate naming in older bilinguals and persons with bilingual aphasia.

Boston Naming Test:: Normative data for older Australians

Individuals aged over 80 years represent the fastest growing segment of the population. It is becoming increasingly important to investigate the effect of age on cognitive functions such as language, in order to document “normal” and “abnormal” functioning. A task commonly used to test naming ability in clinical practice is the Boston Naming Test (BNT). Although norms exist for this age group, they may have limited applications because of small sample sizes on which they were derived. In addition, this test uses stimulus items that have been shown to be culturally specific. This study presents normative data for the BNT for two levels of education and two age bands based on a randomly selected Australian sample of older adults between the age of 81 and 94 years. Frequencies of the most common error types made in this group of nondemented individuals are also reported.

Natural and constrained language production as a function of age and cognitive abilities

Although it is often claimed that verbal abilities are relatively well maintained across the adult lifespan, certain aspects of language production have been found to exhibit cross-sectional differences and longitudinal declines. In the current project age-related differences in controlled and naturalistic elicited language production tasks were examined within the context of a reference battery of cognitive abilities in a moderately large sample of individuals aged 18-90. The results provide support for age-related increases in lexical sophistication and diversity at the discourse level, and declines in grammatical complexity in controlled and naturalistic contexts. Further, age-related decreases in facility with complex grammatical constructions in controlled sentence production were statistically independent of the cognitive abilities assessed in this project.

Effects of perceptual and contextual enrichment on visual confrontation naming in adult aging

PURPOSE

The purpose of this study was to determine the effects of enriching line drawings with color/texture and environmental context as a facilitator of naming speed and accuracy in older adults.

METHOD

Twenty young and 23 older adults named high-frequency picture stimuli from the Boston Naming Test (Kaplan, Goodglass, & Weintraub, 2001) under three conditions: (a) black-and-white items, (b) colorized-texturized items, and (c) scene-primed colored items (e.g., "hammock" preceded 1,000 ms by a backyard scene).

RESULTS

With respect to speeded naming latencies, mixed-model analyses of variance revealed that young adults did not benefit from colorization-texturization but did show scene-priming effects. In contrast, older adults failed to show facilitation effects from either colorized-texturized or scene-primed items. Moreover, older adults were consistently slower to initiate naming than were their younger counterparts across all conditions.

CONCLUSIONS

Perceptual and contextual enrichment of sparse line drawings does not appear to facilitate visual confrontation naming in older adults, whereas younger adults do tend to show benefits of scene priming. We interpret these findings as generally supportive of a processing speed account of age-related object picture-naming difficulty.

Age-related differences in idiom production in adulthood

To investigate whether idiom production was vulnerable to age-related difficulties, we asked 40 younger (ages 18-30) and 40 older healthy adults (ages 60-85) to produce idiomatic expressions in a story-completion task. Younger adults produced significantly more correct idiom responses (73%) than did older adults (60%). When older adults generated partially correct responses, they were less likely than younger participants to eventually produce the complete target idiom (old: 32%; young: 70%); first-word cues after initial failure to retrieve an idiom resulted in more correct idioms for older (24%) than younger (15%) participants. Correlations between age and idiom correctness were positive for the young group and negative for the older group, suggesting mastery of familiar idioms continues into adulthood. Within each group, scores on the Boston Naming Test correlated with performance on the idiom task. Findings for retrieving idiomatic expressions are thus similar to those for retrieving lexical items.

Action and Object Naming in Physiological Aging: An rTMS Study

Word-retrieval difficulties commonly occur in healthy aging. Recent studies report an improved ability to name pictures after the administration of high-frequency repetitive transcranial magnetic stimulation (rTMS) in healthy younger adults and in patients with neurological disease. The aim of this study was to assess the effect of high-frequency rTMS applied to the dorsolateral prefrontal cortex (DLPFC) on picture naming in healthy older adults. High-frequency rTMS was applied to the left and right DLPFC during object and action naming in 13 healthy older adults. The naming latency for actions was shortened after stimulation of the left and right DLPFC compared to application of the sham stimulation. Stimulation was not observed to have any effect on correctness of naming. Our data demonstrate the involvement of the left and right DLPFC in a sample of healthy aging subjects during an action-naming task. The bilateral involvement of the DLPFC in these participants is discussed together with data on younger adults and on Alzheimer's patients.

Lesion characteristics related to treatment improvement in object and action naming for patients with chronic aphasia

Few studies have examined the relationship between degree of lesion in various locations and improvement during treatment in stroke patients with chronic aphasia. The main purpose of this study was to determine whether the degree of lesion in specific brain regions was related to magnitude of improvement over the course of object and action naming treatments.

PARTICIPANTS AND METHODS

Fifteen left hemisphere stroke patients with aphasia participated in treatments for object and/or action naming. Two raters assessed extent of lesion in 18 left hemisphere cortical and subcortical regions of interest (ROIs) on CT or MRI scans. Correlations were calculated between composite basal ganglia, anterior cortical, and posterior cortical lesion ratings, on the one hand, and both pretreatment scores and treatment change for both object and action naming, on the other hand.

RESULTS

Unexpectedly, greater anterior cortical lesion extent was highly correlated with better object and action naming scores prior to treatment and with greater improvement during treatment when partial correlations controlled for total basal ganglia lesion extent (r ranging from .730 to .858). Greater total basal ganglia lesion extent was highly correlated with worse object and action naming scores prior to treatment and with less improvement during treatment when partial correlations controlled for total anterior lesion extent (r ranging from -.623 to -.785). Correlations between degree of posterior cortical lesion and naming indices generally were not significant. No consistent differences were found between the correlations of ROI lesion ratings with object naming versus action naming scores.

CONCLUSION

Large anterior cortical lesions and intactness of the basal ganglia may both contribute to more efficient reorganization of language functions.

Evidence-based systematic review: effects of intensity of treatment and constraint-induced language therapy for individuals with stroke-induced aphasia

PURPOSE

This systematic review summarizes evidence for intensity of treatment and constraint-induced language therapy (CILT) on measures of language impairment and communication activity/participation in individuals with stroke-induced aphasia.

METHOD

A systematic search of the aphasia literature using 15 electronic databases (e.g., PubMed, CINAHL) identified 10 studies meeting inclusion/exclusion criteria. A review panel evaluated studies for methodological quality. Studies were characterized by research stage (i.e., discovery, efficacy, effectiveness, cost-benefit/public policy research), and effect sizes (ESs) were calculated wherever possible.

RESULTS

In chronic aphasia, studies provided modest evidence for more intensive treatment and the positive effects of CILT. In acute aphasia, 1 study evaluated high-intensity treatment positively; no studies examined CILT. Four studies reported discovery research, with quality scores ranging from 3 to 6 of 8 possible markers. Five treatment efficacy studies had quality scores ranging from 5 to 7 of 9 possible markers. One study of treatment effectiveness received a score of 4 of 8 possible markers.

CONCLUSION

Although modest evidence exists for more intensive treatment and CILT for individuals with stroke-induced aphasia, the results of this review should be considered preliminary and, when making treatment decisions, should be used in conjunction with clinical expertise and the client's individual values.

Lexical attrition in younger and older bilingual adults

Healthy monolingual older adults experience changes in their lexical abilities. Bilingual individuals immersed in an environment in which their second language is dominant experience lexical changes, or attrition, in their first language. Changes in lexical skills in the first language of older individuals who are bilinguals, therefore, can be attributed to the typical processes accompanying older age, the typical processes accompanying first-language attrition in bilingual contexts, or both. The challenge, then, in understanding how lexical skills change in bilingual older individuals, lies in dissociating these processes. This paper addresses the difficulty of teasing apart the effects of ageing and attrition in older bilinguals and proposes some solutions. It presents preliminary results from a study of lexical processing in bilingual younger and older individuals. Processing differences were found for the older bilingual participants in their first language (L1), but not in their second language (L2). It is concluded that the lexical behaviour found for older bilinguals in this study can be attributed to L1 attrition and not to processes of ageing. These findings are discussed in the context of previous reports concerning changes in lexical skills associated with typical ageing and those associated with bilingual L1 attrition.

Mimicking aphasic semantic errors in normal speech production: evidence from a novel experimental paradigm

Semantic errors are commonly found in semantic dementia (SD) and some forms of stroke aphasia and provide insights into semantic processing and speech production. Low error rates are found in standard picture naming tasks in normal controls. In order to increase error rates and thus provide an experimental model of aphasic performance, this study utilised a novel method- tempo picture naming. Experiment 1 showed that, compared to standard deadline naming tasks, participants made more errors on the tempo picture naming tasks. Further, RTs were longer and more errors were produced to living items than non-living items a pattern seen in both semantic dementia and semantically-impaired stroke aphasic patients. Experiment 2 showed that providing the initial phoneme as a cue enhanced performance whereas providing an incorrect phonemic cue further reduced performance. These results support the contention that the tempo picture naming paradigm reduces the time allowed for controlled semantic processing causing increased error rates. This experimental procedure would, therefore, appear to mimic the performance of aphasic patients with multi-modal semantic impairment that results from poor semantic control rather than the degradation of semantic representations observed in semantic dementia [Jefferies, E. A., & Lambon Ralph, M. A. (2006). Semantic impairment in stoke aphasia vs. semantic dementia: A case-series comparison. Brain, 129, 2132-2147]. Further implications for theories of semantic cognition and models of speech processing are discussed.

Normative data stratified for age, education, and gender on the Boston Naming Test

Stratified normative data for age, education, and gender are provided for the 60-item Boston Naming Test (BNT) on 1026 older participants ages 50-95 years using overlapping age ranges. Tables are presented that convert BNT raw scores to scaled scores and percentiles. Mild dementia cases were eliminated using a comprehensive cognitive battery. In a companion paper we found significantly poorer mean BNT scores and increasing variability with successively older age groups and decreasing educational levels indicating the need for demographically stratified normative data when determining an individual's degree of impairment. These norms should be clinically useful when assessing suspected dementia cases.

A cross-sectional study of the effects of age, education, and gender on the Boston Naming Test

The effects of age, education, and gender on visual confrontation naming using the 60-item Boston Naming Test (BNT) were studied in 1111 "normal" elderly (ages 50-101) and 61 younger adults (ages 20-49). Significantly poorer mean BNT scores and increasing variability (measured in standard deviations) were found with successively older age groups and with lower educational levels even after stratification on the demographic variables. There was a non-significant trend for males to score slightly higher than females. Age declines on the BNT were considerably greater for this cross-sectional data than for the longitudinal data we previously reported.

Knowledge of semantic categories in normal aged: Influence of education

Semantic memory seems to resist the effects of time, remaining stable even in more advanced ages.