Semantic memory is a type of explicit, declarative long-term memory that stores knowledge extending beyond specific and autobiographical experiences to include general facts (e.g., Australia is south of the equator), word meanings, and object and action information (e.g., swimming is typically done in water).1 Semantic memory not only contains knowledge about objects and actions but also about events. Events involve world knowledge of associated objects, actions, and contexts that commonly co-occur.2–4 For example, semantic memory for events might include knowledge that an action of measuring by a baker would likely involve flour and take place in a kitchen, whereas measuring by a carpenter likely involves wood and takes place in a workshop.4,5 Event representations are thus complex and multidimensional: they connect multiple types of semantic-memory representations, including actions and objects.6

Semantic memory is the starting point for language production and is critically accessed during language comprehension at the word, sentence, and discourse levels.5 It may also serve as the basis for efficacious language treatment for aphasia.7,8 This makes the assessment of semantic memory function critical in patients with post-stroke aphasia. There are clinically established assessments of semantic memory for both objects (Pyramids and Palm Trees [PPT]9) and actions (Kissing and Dancing Test [KDT]10). These assessments use line-drawing pictures and ask participants to make judgments about the relationships among depicted objects or actions. Notably, no words are used in the assessments, only images, removing the need for translations to other languages. Furthermore, these assessments are sensitive to the presence and severity of semantic-memory impairments across a number of neurologically impaired populations, including post-stroke aphasia.10,11 However, a measure of semantic memory for events is not clinically available, despite recent efforts3 to develop such measures (see discussion below).

Event, action, and object knowledge stored in semantic memory are contingent on a person's perceptual, linguistic, and interactive experience with the world.1,12 Therefore, the content of semantic memory may vary based on cultural and linguistic differences. There is preliminary evidence that cultural and linguistic differences affect performance on clinical-standard measures of object- and action-related semantic memory (PPT and KDT), requiring culture-specific norming efforts.13–16 There is also preliminary evidence for cross-linguistic and cross-cultural variability in event representations. Specifically, the co-occurrence between objects, actions, and contexts that make up event representations may differ across cultures, and event representations may also differ across languages, with different lexical–structural encoding of elements like space, number, motion, and event structure.16 Sociolinguistic differences in object, action, and event representations have not been systematically examined to date, nor has their association with the presence of language disorders such as aphasia.

Given potential differences in semantic memory across sociolinguistic backgrounds, it is possible that clinical assessments and cognitive findings from English-speaking samples may not be similar in speakers of other languages. This research serves as a preliminary investigation to assess semantic memory in monolingual Spanish-speaking Colombian adults with and without post-stroke aphasia. In particular, we seek to replicate findings from Dresang et al. (2019), which to our knowledge, has been the only study to directly compare performance across object-, action-, and event-related semantic memory and relate this to the presence of post-stroke aphasia. We investigate whether 2 major findings from this work extend to a sample of adults with a distinct sociolinguistic background—monolingual Spanish-speakers from Colombia.

First, Dresang et al.,3 found that performance on both object and action semantic-memory clinical assessments reliably predicted event semantic memory performance. Consistent with theoretical models of event representations,4–6 these results indicate that semantic memory for events reflects a confluence of object and action knowledge.3Therefore, the first objective of the current research was to assess the reproducibility of these findings by examining whether event semantic memory is associated with object and action semantic-memory performance in Colombian adults with aphasia. Because this finding reflects the structure underlying semantic memory domains, we predicted that the findings reported in Dresang et al.3 should hold true for adults with a Colombian sociolinguistic profile.

Second, Dresang et al.,3 found that clinical-standard semantic memory assessments for objects, actions, and events distinguished neurologically impaired adults from matched neurotypical controls. This finding replicated evidence supporting that clinical-standard measures for object-related (PPT9) and action-related semantic memory (KDT17) can distinguish between individuals with and without neurological impairments, such as aphasia.10,11 Moreover, Dresang and colleagues extended this evidence by finding that event semantic memory reliably differentiated individuals with aphasia from matched neurotypicals as well. Although this finding is consistent with the hypothesis that access to semantic memory is associated with language performance,1,12 it remains unclear to what extent cultural and linguistic differences may affect the relationship between semantic memory and aphasia. Therefore, the second objective of our research was to investigate whether clinical-standard semantic memory assessments for objects, actions, and events distinguished neurologically impaired adults from matched controls in Colombia. Given that semantic memory and event representations, in particular, may be subject to significant sociolinguistic variability,16 there may be differences in the ability of different semantic-memory measures (for objects, actions, and events) to detect the presence of neurological impairment.

For research question 1 regarding the relationship between object, action, and event semantic memory, we found that KDT was a reliable predictor of Event Task performance (β = 0.64, 90% CI: 0.15, 1.28). Although PPT was not a reliable predictor of Event Task performance (β = 0.45, 90% CI: −0.04, 0.93), there was evidence of positive effects when examining its posterior distribution. Specifically, 94% of the posterior distribution for this effect was greater than zero. This provides weak but positive evidence that PPT is associated with Event Task performance. Together, these results provide preliminary evidence that better access to object and action semantic memory may be associated with better Event Task performance in Colombian people with aphasia. Semantic memory performance for all participants is reported in Table 3.

For research question 2, group reliably predicted trial-level accuracy on PPT (β= −0.57, 90% CI: −1.03, −0.11), with participants with aphasia performing worse than controls. Group did not reliably predicted trial-level accuracy on KDT (β= −0.63, 90% CI: −1.25, 0.01) or the Event Task (β= −0.47, 90% CI: −0.01, 0.08); however, there was evidence of positive effects when examining their posterior distributions. Specifically, 95% and 92% of the posterior distributions for group predicting KDT and the Event Task, respectively, were below zero. These results provide weak but positive evidence that participants with aphasia performed worse than controls in both of these assessments. Taking these results into consideration, we provide preliminary evidence that PPT, KDT, and the Event Task could each distinguish between people with and without aphasia in the Colombian context. However, these findings require additional examination and replication.

This work examined semantic memory performance in a group of Colombian adults with post-stroke aphasia and age-matched neurotypical controls to address 2 research questions. First, this study investigated the relationship of impaired performance across domains of semantic memory, examining whether event knowledge impairments were related to action- and object-knowledge impairments, as has previously been found in a sample of English-speaking US stroke survivors with aphasia.3 Second, this study evaluated whether assessments of object-, action-, and event-related semantic memory could distinguish between people with and without aphasia in monolingual Colombian Spanish-speaking adults. This preliminary work provides a step toward developing sociolinguistically sensitive models of cognitive impairments and assessment measures for diverse patient populations.

The current results are largely consistent with previous findings that performance on object- and action-related semantic memory can independently predict event semantic memory performance in adults with aphasia. We found that stronger action semantic performance was robustly associated with stronger event semantic memory. We also found weak, but positive evidence that object semantic memory was associated with event semantic memory. This broadly replicates findings from the same assessment measures used in adults with aphasia in the USA: Dresang and colleagues3 found that both PPT and KDT performance predicted Event Task performance in 26 English-speaking adults with chronic stroke aphasia. If replicated and further examined, these results would support the hypothesis that event representations reflect a combination and possible binding of object and action semantic knowledge.2,3,6 As such, specific variations in world knowledge may not be expected to influence general interactions between object, action, and event domains of semantic memory. However, future work is still required to thoroughly evaluate the contributions of sociolinguistic variations in semantic memory.

In addition, this study offers preliminary evidence suggesting that different semantic-memory measures may distinguish between people with and without aphasia in Spanish-speaking Colombian adults. We found that participant group status reliably predicted performance on object-related semantic memory, but action- and event-related semantic memory did not. However, the posterior distributions provide weak but positive evidence suggesting that all 3 semantic memory assessments could be sensitive to the presence of aphasia, which is consistent with previous findings in monolingual English-speaking adults in the USA.3 Given the semantically rich and experience-driven nature of event knowledge, it is possible that compared to objects, event semantic memory may be susceptible to greater variation across individuals of different cultural and linguistic backgrounds.16,33 Thus, action and event semantic memory measures that are more sociolinguistically appropriate to the target population might improve reliability in distinguishing between Colombian adults with and without aphasia. Additional research is required to characterize sociolinguistic similarities and differences in semantic memory and to establish clinical assessments that are sensitive to semantic memory impairments in diverse patient populations.

There remains a lack of assessments with appropriate psychometric properties that measure semantic memory in Spanish speakers with aphasia, particularly in Latin American countries. More broadly, very few aphasia tests have been standardized and normed in languages other than English, which challenges the reliability and validity of these measures when applied to diverse populations.18 This study takes an important first step in examining semantic memory assessments in monolingual Spanish-speaking Colombian adults with and without aphasia. As a preliminary investigation, this work is limited by a non-standardized translation of the LAST and modest sample sizes. Future work should use a Spanish-normed assessment of aphasia severity and pursue larger sample sizes in this and other Latin American groups. As mentioned above, culturally and linguistically appropriate assessment adaptations are also required. Overall, it is crucial to continue to pursue adaptations of aphasia assessments and treatments to multiple languages.

The current study replicated and extended previous findings that object and action deficits contribute to event memory impairments in aphasia. Furthermore, the current findings provided preliminary evidence that clinical-standard semantic memory assessments could distinguish between Colombian adults with and without aphasia, but further examination is required. This work underscores the need for culturally and linguistically appropriate adaptations of neuropsychological tests so that clinical advancements can reach broader patient populations in Spanish-speaking Latin American communities.

This work involved the use of human subjects. All work described herein has been carried out in accordance with The Code of Ethics of the World Medical Association (Declaration of Helsinki) for experiments involving humans. All subjects had comprehension sufficient to understanding study demands and participation involvement. Informed consent was obtained, and privacy rights of human subjects were observed in accordance with the University of Pittsburgh Institutional Review Board approval.

The Institutional Review Board (IRB) of the University of Pittsburgh approved this international research. Ethical approval from the partner institutions in Colombia was also obtained (Colombian Institute of Neurosciences and the aphasia support group [EFUNA] sponsored by the National University of Colombia). All work was carried out in accordance with The Code of Ethics of the World Medical Association (Declaration of Helsinki).

This research was supported by the Tinker Summer Field Research Grant from the Center for Latin American Studies (University of Pittsburgh) awarded to Yina Quique. It was also supported by the Stanley Prostrednik Health Sciences Grant from the University of Pittsburgh‘s Nationality Rooms and Intercultural Exchange Programs awarded to Haley Dresang. The authors are grateful to the Instituto Colombiano de Neurociencias (Dr. Jorge Eslava) and the EFUNA team at Universidad Nacional de Colombia.