Brain and Language Lab
Aging and Age-Related Disorders
We investigate how language, memory, and other aspects of cognition are affected both in healthy aging and in age-related disorders such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and aphasia, as well as other adult-onset disorders.
HEALTHY AGING
We investigate healthy (typical) aging and its effects on language and various cognitive functions. In one large project, in collaboration with João Veríssimo, Jana Reifegerste, Christos Pliatsikas, Maxine Weinstein, Noreen Goldman, and Dana Glei, we are examining various aspects of cognition in a sample of about 1000 middle-aged to older adults in Taiwan (ages from less than 60 to almost 100). This cross-sectional study tests how aging affects working memory, learning in declarative memory, and aspects of attention and executive function, and how factors such as sex, early-life education, and language background (monolingualism, bilingualism, multilingualism), as well as genotype (e.g., for APOE, among others) might moderate age-related changes.
The findings suggests that whereas both working memory and declarative memory abilities decrease with increasing age, sex interacts with age, such that both types of abilities decrease more for males than females between the ages of about 60 and 100 (Pliatsikas et al., 2019; Reifegerste et al., 2020). Additionally, for both working and declarative memory, more years of early-life education are associated with better performance, moreover with an interaction with sex, such that females benefit more from early-life education than males. For example, that data suggest that women with 16 years of education would have similar declarative memory abilities at age 80 as women with 12 years of education would have at age 60 (Reifegerste et al., 2020).
Strikingly, the findings from this project for attention and executive functions suggest that not all aspects of this broad domain decline in aging. Rather, while some decline ('alerting' and working memory), others actually show age-related improvements ('orienting' and inhibitory control) (Veríssimo et al., 2022). The results are robust, as the study controlled for multiple potentially confounding factors, including overall processing speed, visual declines, and sample selectivity. The findings contradict the widely-accepted view that attention and executive functions show broad declines in aging. Given the importance of attention and executive function, including inhibitory control, in a wide range of everyday behaviors and cognitive domains (e.g., language, math, decision making), the findings have important implications.
Another recent study examined aspects of lexical declines in aging, perhaps the most widespread and frustrating age-related changes in language (e.g., finding the word for that whatchamacallit). The study showed that words that are related to human movements (e.g., knife, hammer, kick) decline significantly less during aging than words that are not (e.g., steak, plant, think) (Reifegerste et al., 2021). This pattern was obtained in three experiments: across three different languages (Dutch, German, English), with two tasks (lexical decision, object naming), with both nouns and verbs, and with both response times and accuracy as the dependent measures. In fact, in two of the experiments the motor-related words did not show any significant age-related declines, even while the non-motor words show declines in all three experiments. Moreover, whether or not (and how much) a word was motor-related moderated declines more than several other variables that were examined at the same time (e.g, word frequency, word length, word age of acquisition, word imageability). Overall, the study suggests that the motor-relatedness of a word can attenuate or even prevent lexical declines in aging. We suggest that the attenuation of lexical declines by motor-relatedness may be due to compensatory roles of procedural memory and/or motor brain circuits (e.g., inferior parietal cortex).
Additionally, in a new behavioral and brain imaging project funded by the National Science Foundation (see News), we are investigating the trajectory of language abilities across the adult lifespan, with a focus on lexical processing. The primary collaborator, who co-wrote the grant and co-designed the study, is Jana Reifegerste. The study tests a new explanatory account for age-related lexical declines. This new hypothesis is called DAD: the Declarative Aging Hypothesis. According to DAD, lexical declines in aging are largely explained by concomitant declines of hippocampal-based declarative memory. The study tests this hypothesis by giving adults from about age 20 to 80+ a range of specific tasks probing word learning and processing, declarative memory, and various other aspects of language and cognition, while also scanning their brains with magnetic resonance imaging.
Publications:
Veríssimo, J., Verhaeghen, P., Goldman, N., Weinstein, M., & Ullman, M. T. (2022). Evidence that ageing yields improvements as well as declines across attention and executive functions. Nature Human Behaviour, 6, 97–110. (Supplementary Information).
Reifegerste, J., Meyer, A., Zwitserlood, P., & Ullman, M.T. (2021). Aging affects steaks more than knives: Evidence that the processing of words related to motor skills is relatively spared in aging. Brain and Language, 218, 104941. (Supplemental Material).
Pliatsikas, C., Veríssimo, J., Babcock, L., Pullman, M. Y., Glei, D. A., Weinstein, M., Goldman, N., & Ullman, M. T. (2019). Working memory in older adults declines with age, but is modulated by sex and education. Quarterly Journal of Experimental Psychology, 72(6), 1308-1327. (Supplemental Material).
ALZHEIMER'S DISEASE
We are interested in the neurocognition of language and memory in Alzheimer’s disease (AD). We have found that patients with AD have more difficulty with lexical than grammatical abilities, both in English (Ullman et al., 1997) and Italian (Walenski et al., 2009). This may be due to the dependence of lexical abilities on declarative memory, which is impaired in the disorder, while grammar depends importantly on procedural memory, which remains relatively spared (Ullman et al., 1997; Ullman, 2004).
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PARKINSON'S DISEASE
We are interested in the neurocognitive of language and memory in Parkinson's disease (PD). We have found that patients with PD have more difficulty with grammatical than lexical abilities (Ullman et al., 1997; Johari et al., 2019a; Johari et al., 2019b; Reifegerste et al., 2020). This may be explained at least in part by the dependence of grammatical abilities on procedural memory, which is impaired in the disorder (Clark et al., 2014), while lexical memory depends importantly on declarative memory, which remains relatively spared in non-demented PD patients (Reifegerste et al., 2020). Interestingly, we found that deep brain stimulation of the basal ganglia (subthalamic nucleus) leads to degraded performance at grammatical but not lexical abilities, while it concurrently results in improved motor function (Phillips et al., 2012). Evidence also suggests that declarative memory may compensate for procedural memory and other deficits in Parkinson’s disease (Ullman & Pullman, 2015). In fact, as expected due to a greater dependence of grammar on declarative memory in women than men (see Effects of Sex Differences), male PD patients show more grammatical impairments than female PD patients, apparently due to more successful grammatical compensation by declarative memory among the female patients (Ullman et al., 2002; Johari et al., 2019; Reifegerste et al., 2020).
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HUNTINGTON'S DISEASE
We are interested in the neurocognition of language and memory in Huntington’s disease (HD). We have found that patients with HD show evidence of unsuppressed grammatical rule use, both in English (Ullman et al., 1997) and in Hungarian, even in individuals who are pre-symptomatic (Nemeth et al., 2012). This pattern may be due to the dependence of grammatical abilities on the basal ganglia and procedural memory, which are abnormal in the disorder; in contrast, lexical memory depends importantly on declarative memory, which remains relatively spared in HD (Ullman et al., 1997; Ullman, 2004).
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APHASIA
Are lexical and grammatical abilities, in morphology and in other aspects of language, dissociable across different types of aphasia? Are lexical and grammatical impairments linked to lesions of particular brain structures? What is the relation between these impairments and declarative and procedural memory? What neurocognitive systems do aphasics use to compensate for their deficits? We are investigating these and related questions in aphasia.
Evidence suggests that anterior aphasia, which is associated with frontal lesions, is linked to grammatical more than lexical impairments, whereas posterior aphasia, which is associated with temporal/parietal lesions, is linked to lexical more than grammatical difficulties (Ullman et al., 1997; Ullman et al., 2005). This may be due to grammar being learned and processed primarily in procedural memory, while lexical memory depends on declarative memory (Ullman et al., 1997; Ullman, 2004). Interestingly, as with various other disorders (see Declarative Memory Compensation Hypothesis) lexical/declarative memory appears to compensate for grammatical deficits in aphasia (Drury & Ullman, 2002; Ullman & Pullman, 2015).
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OTHER ADULT-ONSET DISORDERS
We are also interested in language and memory in other adult-onset disorders, including amnesia (in the well-known patient H.M.) and patients with cerebellar abnormalities or lesions.