The influence of age and ASD on verbal fluency networks

Abstract

Background:The integrity and connectivity of the frontal lobe, which subserves fluency, may be compromised by both ASD and aging. Alternate networks often integrate to help compensate for compromised functions during aging. We used network analyses to study how compensation may overcome age-related compromised in individuals with ASD.Method: Participants consisted of middle-aged (40-60; n=24) or young (18-25; n=18) righthanded males who have a diagnosis of ASD, and age-and IQ-matched control participants (n=20, 14, respectively). All performed tests of language and executive functioning and a fluency functional MRI task. We first used group individual component analysis (ICA) for each of the 4 groups to determine whether different networks were engaged. An SPM analysis was used to compare activity detected in the network nodes from the ICA analyses. Results:The individuals with ASD performed more slowly on two cognitive tasks (Stroop word reading and Trailmaking Part A). The 4 groups engaged different networks during the fluency fMRI task despite equivalent performance. Comparisons of specific regions within these networks indicated younger individuals had greater engagement of the thalamus and supplementary speech area, while older adults engaged the superior temporal gyrus. Individuals with ASD did not disengage from the Default Mode Network during word generation. Conclusion:Interactions between diagnosis and aging were not found in this study of young and middle-aged men, but evidence for differential engagement of compensatory networks was observed.

Short‐Term Memory Span and Cross‐Modality Integration in Younger and Older Adults With and Without Autism Spectrum Disorder

“…Geurts and Vissers [2012], by contrast found greater age‐related performance differences in ASD than in TD on immediate recall from visual memory but not in verbal memory leading them to suggest that since some cognitive difficulties (such as with verbal memory, planning and fluency) appear to reduce with age, growing older might be a protective factor in these domains in individuals with ASD. Although it is tempting to draw a similar conclusion from the findings of the present study, an alternative conclusion might be in terms of recruitment of compensatory neural mechanisms as was found, for example, by Baxter et al [2019].…”

Intact fluency in autism? A comprehensive approach of verbal fluency task including word imageability and concreteness

“…Regarding which we also have to consider the possibility that a certain subset of the people with ASD group mobilizes different brain networks and behavioral elements to compensate, a proposal of which F I G U R E 4 Proportion of words produced by ASD and NTP groups getting high (6 or above) concreteness (panel a) and imageability (panel b) scores during the first and second part of the task. The top and the bottom of the box show the upper (Q3) and lower (Q1) quartiles, the line dividing the box represents the median, and notches show 95% confidence interval around the median was underlined by the recent neuroimaging studies of Baxter et al (2019) and Beacher et al (2012). Furthermore, this result might lead to the questioning of a verbal fluency initiation deficit for autistic participants without intellectual disability or language impairment.…”

“…The results above, thus, point us to the idea that ASD participants without intellectual disability and language impairment may inherently perform just as well in a fluency test as NTP participants or otherwise be using compensatory mechanisms. Regarding which we also have to consider the possibility that a certain subset of the people with ASD group mobilizes different brain networks and behavioral elements to compensate, a proposal of which was underlined by the recent neuroimaging studies of Baxter et al ( 2019 ) and Beacher et al ( 2012 ). Furthermore, this result might lead to the questioning of a verbal fluency initiation deficit for autistic participants without intellectual disability or language impairment.…”

“…Even though research of verbal fluency in ASD has mostly focused on high functioning autism (HFA) or Asperger syndrome (Borkowska, 2015 ; Carmo et al, 2015 ; Corbett et al, 2009 ; Inokuchi & Kamio, 2013 ; Kenworthy et al, 2009 ; Spek et al, 2009 ), the studies reported contradicting results. The mentioned studies either found significant impairment in both semantic and phonemic tasks (Corbett et al, 2009 ; Czermainski et al, 2014 ; Kenworthy et al, 2009 ; Kleinhans et al, 2005 ), or similar performance (Borkowska, 2015 ) to the neurotypical group (NTP) but the use of different brain structures or compensatory methods (Baxter et al, 2019 ; Beacher et al, 2012 ). Similarly, different results can be found for clustering and switching: Begeer et al ( 2014 ) found a similar total number of words with the ASD group producing longer but fewer clusters while Ehlen et al ( 2020 ) observed, that the ASD group produced smaller clusters and also fewer words then the NTP group.…”

“…Similarly, different results can be found for clustering and switching: Begeer et al ( 2014 ) found a similar total number of words with the ASD group producing longer but fewer clusters while Ehlen et al ( 2020 ) observed, that the ASD group produced smaller clusters and also fewer words then the NTP group. On the other hand, up until the 2010s, researchers predominantly tested the verbal fluency of children with ASD (Begeer et al, 2014 ; Corbett et al, 2009 ; Czermainski et al, 2014 ; Kenworthy et al, 2009 ; Sauzéon et al, 2004 ) while the scientific research of adults has been more common in the last few years (Baxter et al, 2019 ; Carmo et al, 2015 ; Ehlen et al, 2020 ; Kiep & Spek, 2017 ; Sauzéon et al, 2004 ). On the assumption that measuring only the overall score in fluency tasks does not capture essential qualitative aspects of the performance research, Carmo et al ( 2017 ) have also perceived verbal fluency as a function of time and observed performance across time intervals.…”