On comprehension across the adult lifespan

Syntactic complexity differentially affects auditory sentence comprehension performance for individuals with age-related hearing loss

Objectives

This study examined whether older adults with hearing loss (HL) experience greater difficulties in auditory sentence comprehension compared to those with typical-hearing (TH) when the linguistic burdens of syntactic complexity were systematically manipulated by varying either the sentence type (active vs. passive) or sentence length (3- vs. 4-phrases).

Methods

A total of 22 individuals with HL and 24 controls participated in the study, completing sentence comprehension test (SCT), standardized memory assessments, and pure-tone audiometry tests. Generalized linear mixed effects models were employed to compare the effects of sentence type and length on SCT accuracy, while Pearson correlation coefficients were conducted to explore the relationships between SCT accuracy and other factors. Additionally, stepwise regression analyses were employed to identify memory-related predictors of sentence comprehension ability.

Results

Older adults with HL exhibited poorer performance on passive sentences than on active sentences compared to controls, while the sentence length was controlled. Greater difficulties on passive sentences were linked to working memory capacity, emerging as the most significant predictor for the comprehension of passive sentences among participants with HL.

Conclusion

Our findings contribute to the understanding of the linguistic-cognitive deficits linked to age-related hearing loss by demonstrating its detrimental impact on the processing of passive sentences. Cognitively healthy adults with hearing difficulties may face challenges in comprehending syntactically more complex sentences that require higher computational demands, particularly in working memory allocation.

Sentence Comprehension in Primary Progressive Aphasia: A Study of the Application of the Brazilian Version of the Test for the Reception of Grammar (TROG2-Br)

Sentence-comprehension deficits have been described in patients with primary progressive aphasia (PPA). However, most instruments to address this domain in more detail and in a clinical context have not been adapted and translated into several languages, posing limitations to clinical practice and cross-language research.

Objectives

The study aimed to (1) test the applicability of the Brazilian version of the Test for Reception of Grammar (TROG2-Br) to detect morphosyntactic deficits in patients with PPA; (2) investigate the association between performance in the test and sociodemographic and clinical variables (age, years of formal education, and disease duration); (3) characterize the performance of individuals presenting with the three more common variants of PPA (non-fluent, semantic, and logopenic) and mixed PPA (PPA-Mx) and analyze whether TROG-2 may assist in the distinction of these clinical profiles.

Methods

A total of 74 cognitively healthy participants and 34 individuals diagnosed with PPA were assessed with TROG2-Br. Overall scores (correct items, passed blocks), types, and categories of errors were analyzed.

Results

In controls, block scores were significantly correlated with years of formal education (Spearman's r = 0.33, p = 004) but not with age. In PPA, age, education, and disease duration were not significantly associated with performance in the test. Controls presented a significantly higher performance on TROG2-Br compared to PPA individuals and their errors pattern pointed to mild general cognitive processing difficulties (attention, working memory). PPA error types pointed to processing and morphosyntactic deficits in nonfluent or agrammatic PPA, (PPA-NF/A), logopenic PPA (PPA-L), and PPA-Mx. The semantic PPA (PPA-S) subgroup was qualitatively more similar to controls (processing difficulties and lower percentage of morphosyntactic errors). TROG2-Br presented good internal consistency and concurrent validity.

Discussion

Our results corroborate findings with TROG-2 in other populations. The performance of typical older adults with heterogeneous levels of education is discussed along with recommendations for clinical use of the test and future directions of research.

Syntactic Complexity as a Linguistic Marker to Differentiate Mild Cognitive Impairment From Normal Aging

Purpose In this study, we sought to identify critical linguistic markers that can differentiate sentence processing of individuals with mild cognitive impairment (MCI) from the sentence processing of normal-aging populations by manipulating sentences' linguistic complexity. We investigated whether passive sentences, as linguistically complex structures, can serve as linguistic markers that can contribute to diagnoses that distinguish MCI from normal aging. Method In total, 52 participants, including 26 adults with amnestic MCI and 26 cognitively unimpaired adults, participated in the study. All participants were native speakers of Korean. We administered the two subsets of active and passive conditions using a sentence-picture paradigm with semantically reversible sentences to both groups. Results A mixed-effects model using PROC NLMIXED demonstrated that the MCI group exhibited differentially greater difficulty in processing passive than active sentences compared to the normal-aging group. A logistic regression fitted with the PROC LOGISTIC model identified the sum of the passive sentences, with age and education effects as the best models to distinguish individuals with MCI from the normal-aging group. Conclusion Sentence comprehension deficits emerged in the MCI stage when the syntactic complexity was increased. Furthermore, a passive structure was the best predictor for efficiently distinguishing the MCI group from the normal-aging group. These results are clinically and theoretically important, given that linguistic complexity can serve as a critical behavioral marker in the detection of early symptoms associated with linguistic-cognitive decline.

Subjective rating scale for discourse: Evidence from the efficacy of subjective rating scale in amnestic mild cognitive impairments

In clinical settings, the language ability of patients with neurologic communication disorders have been measured by quantitative parameters such as the total number of words in dialogue and picture description tasks. However, this quantitative analysis requires a long period of time in order to analyze the quantitative parameters, and results can differ according to discourse tasks. The purposes of this study are to explore whether SR-D may predict the quantitative measures of discourse tasks. Forty patients with amnestic MCI and 40 normal elderly participated in the study. We gathered responses to 10 items regarding SR-D and analyzed the quantitative measures of narrative discourse through 3 discourse tasks (i.e, picture description, dialogue, procedural discourse). We found significant differences in MLTW, CIU, and SR-D scores between the 2 groups. In particular, 4 items were significantly correlated with the performance of MLTW and CIU. Sensitivity and specificity of these 4 items were 100% and 75%, respectively. In terms of economic opportunity costs, objective measures cannot be evaluated to be practical, since it is used in research rather than clinical diagnosis in general. Therefore, evaluation of discourse using a few items proven in its sensitivity and specificity could allow a wide use of such measure in not only research but also in clinical diagnosis. These findings suggest that subjective measures of narrative discourse may be valid with objective language tests to predict individual discourse performance.

Effects of age, working memory, and word order on passive-sentence comprehension: evidence from a verb-final language

BACKGROUND

The purpose of the current study was to investigate the effects of working-memory (WM) capacity on age-related changes in abilities to comprehend passive sentences when the word order was systematically manipulated.

METHODS

A total of 134 individuals participated in the study. The sentence-comprehension task consisted of the canonical and non-canonical word-order conditions. A composite measure of WM scores was used as an index of WM capacity.

RESULTS

Participants exhibited worse performance on sentences with non-canonical word order than canonical word order. The two-way interaction between age and WM was significant, suggesting that WM effects were greater than age effects on the task.

CONCLUSIONS

WM capacity effects on passive-sentence comprehension increased dramatically as people aged, suggesting that those who have larger WM capacity are less vulnerable to age-related changes in sentence-comprehension abilities. WM capacity may serve as a cognitive reserve associated with sentence-comprehension abilities for elderly adults.

Encoding Operations and the Next-in-Line Effect

In a verbal interaction, people take turns speaking. Later, they may have difficulty remembering certain parts of the interaction. In particular, they may not recall what was said just before they began to speak. Previous research indicates that this next-in-line memory deficit reflects a failure at encoding, rather than retrieval. The current study assessed two explanations for the next-in-line encoding failure. One explanation locates the failure in a peripheral encoding operation, eye contact; the other locates it in a central operation, elaborative rehearsal. In the current study, verbal elaboration eliminated the next-in-line effect, and eye contact did not. As these results suggest, the next-in-line memory deficit reflects a failure at elaborative rehearsal.

Influences of word predictability and type of masker noise on intelligibility of sung text in live concerts

Vocal music is often intended to convey meaning, but how effectively this is achieved is poorly understood. This study systematically assessed the influence of three non-phonetic factors on the intelligibility of sung words in six public concerts in different venues: word predictability from sentence context, type of masker noise (spoken babble, sung vowels, [∫(w)]), and signal-to-noise ratio (SNR). Stimuli were sung live by a professional a cappella ensemble with one male singing target sentences and five others (two female) producing the masker sounds. The concert audiences (N = 319) reported the final word of each sentence using a handheld voting device, from four phonetically- and semantically-controlled written alternatives projected onto a screen after the sentence was sung. Although overall accuracy differed between performances, intelligibility patterns were robust across concerts. They included predicted main effects of masker noise type ([∫(w)] masking least disruptive, babble most), SNR (high > low), semantic predictability (high > low), listener age (young > old), and listener language status (native > non-native), and some strong interactions. These results suggest that, despite acoustic differences between sung and spoken words and the unusual and varied experimental venues, key findings from traditional speech research apply to sung words, given appropriate musical composition.

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.

Effects of hypertension and diabetes on sentence comprehension in aging

OBJECTIVES

To assess the impact of hypertension and diabetes mellitus on sentence comprehension in older adults.

METHOD

Two hundred and ninety-five adults aged 55 to 84 (52% men) participated in this study. Self-report mail survey combined with medical evaluations were used to determine eligibility. Multiple sources were used to determine whether hypertension and diabetes were present or absent and controlled or uncontrolled. Sentence comprehension was evaluated with two tasks: embedded sentences (ES) and sentences with multiple negatives (MN). Outcome measures were percent accuracy and mean reaction time of correct responses on each task.

RESULTS

Regression models adjusted for age, gender, and education showed that the presence of hypertension impaired comprehension on the multiple negatives task (p < .01), whereas the presence of diabetes impaired the comprehension of embedded sentences (p < .05). Uncontrolled diabetes significantly impaired accurate comprehension of sentences with multiple negatives (p < .05). No significant patterns were found for reaction time.

DISCUSSION

The presence of hypertension and diabetes adversely affected sentence comprehension, but the relative contribution of each was different. These findings support the researchers' earlier speculations on the neurobiological mechanisms underlying the effects of hypertension and diabetes on language and cognition in aging. Uncontrolled disease status demonstrated more complicated age-related effects on sentence processing, highlighting the clinical importance for cognitive aging of identifying and managing vascular risk factors.

The clinical problem of symptomatic Alzheimer disease and mild cognitive impairment

Alzheimer disease (AD) is the most common cause of dementia in the elderly. Clinicopathological studies support the presence of a long preclinical phase of the disease, with the initial deposition of AD pathology estimated to begin approximately 10-15 years prior to the onset of clinical symptoms. The hallmark clinical phenotype of AD is a gradual and progressive decline in two or more cognitive domains, most commonly involving episodic memory and executive functions, that is sufficient to cause social or occupational impairment. Current diagnostic criteria can accurately identify AD in the majority of cases. As disease-modifying therapies are being developed, there is growing interest in the identification of individuals in the earliest symptomatic, as well as presymptomatic, stages of disease, because it is in this population that such therapies may have the greatest chance of success. The use of informant-based methods to establish cognitive and functional decline of an individual from previously attained levels of performance best allows for the identification of individuals in the very mildest stages of cognitive impairment.

Listening comprehension across the adult lifespan

OBJECTIVES

Although age-related declines in perceiving spoken language are well established, the primary focus of research has been on perception of phonemes, words, and sentences. In contrast, relatively few investigations have been directed at establishing the effects of age on the comprehension of extended spoken passages. Moreover, most previous work has used extreme-group designs in which the performance of a group of young adults is contrasted with that of a group of older adults and little if any information is available regarding changes in listening comprehension across the adult lifespan. Accordingly, the goals of the current investigation were to determine whether there are age differences in listening comprehension across the adult lifespan and, if so, whether similar trajectories are observed for age-related changes in auditory sensitivity and listening comprehension.

DESIGN

This study used a cross-sectional lifespan design in which approximately 60 individuals in each of 7 decades, from age 20 to 89 yr (a total of 433 participants), were tested on three different measures of listening comprehension. In addition, we obtained measures of auditory sensitivity from all participants.

RESULTS

Changes in auditory sensitivity across the adult lifespan exhibited the progressive high-frequency loss typical of age-related hearing impairment. Performance on the listening comprehension measures, however, demonstrated a very different pattern, with scores on all measures remaining relatively stable until age 65 to 70 yr, after which significant declines were observed. Follow-up analyses indicated that this same general pattern was observed across three different types of passages (lectures, interviews, and narratives) and three different question types (information, integration, and inference). Multiple regression analyses indicated that low-frequency pure-tone average was the single largest contributor to age-related variance in listening comprehension for individuals older than 65 yr, but that age accounted for significant variance even after controlling for auditory sensitivity.

CONCLUSIONS

Results suggest that age-related reductions in auditory sensitivity account for a sizable portion of individual variance in listening comprehension that was observed across the adult lifespan. Other potential contributors including a possible role for age-related declines in perceptual and cognitive abilities are discussed. Clinically, the results suggest that amplification is likely to improve listening comprehension but that increased audibility alone may not be sufficient to maintain listening comprehension beyond age 65 and 70 yr. Additional research will be needed to identify potential target abilities for training or other rehabilitation procedures that could supplement sensory aids to provide additional improvements in listening comprehension.

The Carhart Memorial Lecture, American Auditory Society, Salt Lake City, Utah 1996. Phoneme and word recognition for words in isolation and in sentences

OBJECTIVE

To evaluate relations among scores for phonemes, words in isolation, and words in sentences for listeners with normal hearing and for listeners with sensorineural hearing loss.

DESIGN

Ten-word lists of consonant-vowel-consonant monosyllables with each list utilizing the same 10 vowels and 20 consonants (Boothroyd, 1968) were devised and recorded. These words also were incorporated into contextually correct sentences and recorded by the same talker. The materials were presented in quiet to 36 listeners with normal hearing and to 876 listeners (1260 ears) with sensorineural hearing loss. Formulae derived by Boothroyd and Nittrouer (1988) to relate scores for phonemes, words, and sentences were applied to the data.

RESULTS

Phoneme scoring yielded scores that were on the order of 20% higher than scores for whole words heard in isolation, and scores for words in sentences were about 20% higher than when the same words were heard singly. Relations among scores for phonemes, words in isolation, and words in sentences were very similar to those observed by Boothroyd and Nittrouer (1988). The constants derived from application of their formulae to our data were very similar to the constants Boothroyd and Nittrouer obtained for a different set of materials presented against a noise background to listeners with normal hearing. Further, the constants were similar for our group of listeners with normal hearing and our large sample of listeners with sensorineural hearing loss.

CONCLUSIONS

1) These findings support Bilger's (1984) unifying assumptions that speech recognition is a single construct; therefore, scores on all speech recognition tests must be related and scores on one speech recognition test should be predictive of scores on other tests. 2) Advantages of phoneme scoring include: A) It increases the sample size of scored items for a given list of words, thereby reducing variability in test results. B) Statistical equivalence of phoneme scores for the same 30 phonemes in each of two isophonemic word lists can be evaluated quickly and easily by applying the binomial distribution model to the scores (Thornton & Raffin, 1978). C) Phoneme scores are reasonably accurate predictors of recognition of words in the contextually correct but generally low probability sentences used in this study.

Spontaneous language production and aging: sex and educational effects

Sex and educational level effects on spontaneous language production at different ages were analyzed in a 180-normal subject sample taken from the general population. Subjects were divided into groups according to three variables: (1) age (16-30, 31-50, and 51-65 years), (2) educational level (3-7, 8-12 and more than 12 years of formal educational), and (3) sex (males and females) with 10 subjects in each cell. The oral description of the Plate #1 ("The Cookie Theft") from the Boston Diagnostic Aphasia Examination (Goodglass & Kaplan, 1972) was selected. Number of nouns, verbs, adjectives and grammatical connectors were scored for each subject's picture description. It was concluded that: (1) the ratio among different phrase elements was very uniform across age, educational level and sex groups; (2) the total number of words used to describe the "The Cookie Theft" picture significantly increased with the subject's educational level; (3) the amount of spontaneous language in general decreased with age; however, a significant interaction-effect between age and sex was observed. A steady and pronounced spontaneous language decrease across age-groups was observed in males. However, only mild differences across age-groups were observed in female subjects. It was hypothetized that language changes during aging are strongly sex-dependent: while in men spontaneous language rapidly decreases with aging, in women spontaneous language production remains quite well-preserved.

A quantitative dendritic analysis of Wernicke's area in humans. II. Gender, hemispheric, and environmental factors

This quantitative Golgi study extends our investigation of relationships between cortical dendrite systems in humans and higher cognitive functions. Here we examine the relationship between the basilar dendrites of supragranular pyramidal cells in Wernicke's area and selected intrinsic (i.e., gender and hemisphere) and extrinsic (i.e., education and personal history) variables. Tissue was obtained from 20 neurologically normal right-handers: 10 males (Mage = 52.2) and 10 females (Mage = 47.8). Several independent variables were investigated: GENDER (male, female), HEMISPHERE (left, right), and EDUCATION (less than high school, high school, and university). These were evaluated according to Total Dendritic Length, Mean Dendritic Length, and Dendritic Segment Count. A distinction was made between proximal (1st, 2nd, and 3rd order) and ontogenetically later developing distal (4th order and above) branches. There was significant interindividual variation in dendritic measurements, which roughly reflected individuals' personal backgrounds. Females exhibited slightly greater dendritic values and variability than males across the age range examined. On the whole, the left hemisphere maintained a slight advantage over the right hemisphere for all dendritic measures when all subjects were pooled, but these differences were not in a consistent direction across individuals. Education had a consistent and substantial effect such that dendritic measures increased as educational levels increased. Dendritic differences between independent variable levels were most clearly illustrated in the total dendritic length of 3rd and 4th order branches. Distal dendritic branches appeared to exhibit greater epigenetic flexibility than proximal dendrites. The present findings concur with environmental enrichment research results in animals and suggest that dendritic systems in humans function as a sensitive indicator of an individual's (a)vocational activities.