Wednesday, January 17, 2018

Reading :: Executive Functions and the Frontal Lobes

Executive Functions and the Frontal Lobes: A Lifespan Perspective
Edited by Peter J. Anderson,‎ Vicki Anderson,‎ and Rani Jacobs

In this collection, the authors discuss the fascinating subject of executive functions, something that I have lightly covered on this blog in my recent reviews of books on aphasia. This collection, however, covers the entire lifespan: childhood to old age, healthy development to recoveries from injuries.

"Executive function," Peter J. Anderson explains in Chapter 1 ("Towards a developmental model of executive function"), "is not a unitary cognitive process, but instead is a psychological construct that is composed of multiple interrelated high-level cognitive skills" (p.3). It is
a collection of interrelated functions, or processes, which are responsible for goal-directed or future-oriented behavior, and have been referred to as the 'conductor' which controls, organizes, and directs cognitive activity, emotional responses and behavior (Gioia, Isquith, & Guy, 2001). The key elements of executive function include (a) anticipation and deployment of attention; (b) impulse control and self-regulation; (c) initiation of activity; (d) working memory; (e) mental flexibility and utilization of feedback; (f) planning ability and organization; and (g) selection of efficient problem-solving strategies. (p.4)
Anderson overviews several models of executive function, including the supervisory attentional system (SAS) model (pp.7-9), the working memory model (pp.9-11), the model of executive (self-regulatory) functions (pp.11-13), components of executive functions (pp.13-14), problem-solving framework (pp.14-15), and executive control system (pp.15-18).  He identifies strengths and weaknesses of each. (Note: In Chapter 17, "Models for the rehabilitation of executive impairments," authors Barbara A. Wilson and Jonathan Evans state that the SAS model is closely related to Luria's conception of problem-solving; p.389).

In Chapter 2, Cinzia R. De Luca and Richard J. Leventer discuss "Developmental trajectories of executive functions across the lifespan." They begin by explaining that EF are not just localized to the frontal lobes (and call out Luria 1973 for treating the two as synonymous) (p.24). But the frontal lobes do play a large role in EFs, and the frontal lobes degenerate first—both in aging and in pathological dementias (p.25).

The authors break down development into several stages and provide detailed tables for each stage, allowing us to see how brain development and EF relate by year. For instance, we find that at age 4, children increase both gray and white matter volumes as well as metabolism; they see improved cognitive flexibility at this age (p.34). Between ages 9-12, most EFs demonstrate a spurt, including working memory, strategic thinking, fluency, and goal-directed behavior (p.35). Through adolescence, white matter increases and gray matter volume decreases (p.36). From the mid-20s until the late 30s, "the major change in the PFC [prefrontal cortex] is the continued steady increase in myelination" or the fatty insulation around axions (p.39). Peak EF skills are realized from 20-29. Alas, "brain weight begins to decline from age 30, dropping by 10% to age 90," correlating with a long slow decline in EF skills (p.40).

But there is hope for us above 30. Although older people perform more poorly on clinical planning tasks, they perform as well as a younger cohort on ecologically valid planning tasks (p.41). The discrepancy reflects "the greater opportunity to effectively apply compensatory strategies and knowledge to successfully perform everyday task types" (p.41)—in other words, older people have learned mediatory strategies or picked up mediatory tools to which they can shift some of the cognitive burden.

In Chapter 3, Louise H. Phillips and Julie D. Henry discuss "Adult aging and executive functioning" in more detail. They note that since each EF "involves a complex network of brain areas and multiple cognitive processes," aging does not affect all in the same way (p.58). Interestingly, older adults see more prefrontal activation, and more bilateralized activation, than younger adults when performing the same cognitive tasks—likely because prefrontal decline requires more neural recruitment to compensate (pp.58-59).

The authors examine the evidence of how aging affects various EFs. Interestingly, in older people, planning is slower and involves more moves, but goal conflict handling—which is involved in the most difficult planning tasks—does not appear to decline (pp.68-69). The authors conclude by calling for more research on "well-practiced or socially relevant executive tasks" (p.73).

In Chapter 8, "Assessment of behavioral aspects of executive function," authors Gerald A. Gioia, Peter K. Isquith, and Laura E. Kenealy begin by discussing ecological validity and the assessment of EF. They define ecological validity as "predictive value of functioning in the everyday environment" (p.179) and contrast it with traditional (construct) validity (p.181). Ecological validity has obvious ramifications for "implications and predictions for the individual in his or her everyday milieu" (p.181). The authors overview various assessment methods to get at ecological validity.

In Chapter 18, Mark Ylvisaker and Timothy Feeney's "Helping children without making them helpless: Facilitating development of executive self-regulation in children and adolescents," the authors specifically examine self-regulation in children. Children often have "weak self-regulation" if they have "neurological impairment or immaturity" such as ADHD; "chaotic, unpredictable, disorganized home environments"; "weak emotional attachments" to adults, such as children in the foster care system; "few opportunities for legitimate control over events in their lives"; and developmental immaturity (p.413). The authors embrace a Vygotskian approach and use "a typical developmental template for developing intervention and support strategies" (p.414). One typically Vygotskian approach they use is to provide a script that children can internalize "as automatic SR [self-regulation] self-talk" (p.416). The authors provide several cases to illustrate this approach. They also describe teaching compensatory strategies (p.425). They conclude by advocating the approach of identifying strengths and goals as opposed to "pathology-oriented interventions that focus primarily on identifying deficits for purposes of their amelioration" (p.432).

Overall, the book was fascinating to me. After reading the foundational works of Vygotsky and Luria, I have been thinking about how a Vygotskian approach to workplace/professional writing might involve better understanding the EFs that collectively support writing and information tasks. Reading this collection, in addition to similar work on aphasia, gave me a much better idea of what has been built on that Vygotsky-Luria foundation, as well as how complicated our cognition really is. If you're similarly interested in these themes, I recommend this book.

Wednesday, January 10, 2018

Reading :: The Power of Intuition

The Power of Intuition: How to Use Your Gut Feelings to Make Better Decisions at Work
By Gary Klein

Over ten years ago, I reviewed Klein's Sources of Power, in which he discusses decision-making in high-pressure situations (by firefighters, soldiers, neonatal nurses, etc.). Klein had expected that under pressure, decision-makers would identify two potential courses of action, compare them, then select one. Instead, he discovered that they typically only thought about one course of action, quickly modified it by modeling it mentally based on their previous experiences, then took it. He began discussing this process under the heading of intuition, which he defines as "the way we translate our experience into action" (p.xiv, his emphasis)

This book builds on that notion of insight—and uses many of the same studies for grounding. Here, Klein is addressing professionals (and especially managers) who want to build intuition at work. How is it built? How can you apply it? How do you safeguard it so that your team can act on it? Drawing on his experience in teaching intuition, Klein identifies principles for developing intuition and using it to lead effectively. He does this with plentiful examples from research and consulting, but he also offers several decision-making exercises (DMX) and discusses how to build your own DMXes to help prepare your own teams.

If you're interested in improving your decision-making skills in specific activities—or those of your team—take a look.

Reading :: The Entrepreneurial State

The Entrepreneurial State: Debunking Public vs. Private Sector Myths
By Mariana Mazzucado

A colleague recommended that I pick up this book, which was declared a Financial Times best book of the year. The book argues that, despite "the pervasive myth that the state is a laggard, bureaucratic apparatus at odds with a dynamic private sector," in reality "the state is, and has been, our boldest and most valuable innovator" (back cover). But because of this myth, the US government in particular has been disinvesting from innovation, with potentially negative consequences.

The book is closely argued and I'm sure it's very convincing. Yet I have very few notes in it, primarily because the thesis does not seem that radical or interesting to me. Yes, the State funds a lot of different innovation projects—including basic research in universities, innovation networks, and entrepreneurship training—and in doing so, takes many risks that would not otherwise be taken on by the private sector. I've seen plenty of examples, especially in my ongoing work with IC2.

If you do find that thesis to be radical or interesting, however, do take a look at the book. Mazzucato does a nice job of laying out specific claims and substantiating them with both hard numbers and specific case studies.

Reading :: Aphasia and Related Neurogenic Language Disorders

Aphasia and Related Neurogenic Language Disorders (Third Edition)
Edited by Leonard L. LaPointe

This collection overviews different kinds of aphasia (e.g., Broca's, Wernicke's) and related disorders (dementia, traumatic brain injury) as well as related issues (functional neuroimaging; social and life approaches to intervention; pragmatics). The scope is large, but less focused on diagnosis and therapy than other aphasia books I've recently read. I won't treat the book exhaustively, but I'll pull out some interesting parts from the chapters.

The book starts with LaPointe's chapter "Foundations: Adaptation, accommodation, and Aristos," which describes how people acquire aphasia, what it is, and how people react to it. Crucially, LaPointe says (quoting MacKenzie Buck), aphasia is a "family disease": some argue that "the social context, especially the family, must be an integral part of the condition" (p.5). Drawing on Morse and Johnson's 1991 ethnography, LaPointe describes stages in the illness experience (p.7), including the family and identity dynamics at play in diagnosing, compensating for, and accepting aphasia (pp.8-11).

Along these lines, in her chapter "Social and Life Participation Approaches to Aphasia Intervention," Roberta J. Elman overviews the work on social approaches in the 1980s and 1990s, quoting an earlier LaPointe publication to argue that we need a "sociology of aphasia" (p.41). One practical approach is the "life participation approach to aphasia (LPAA)," in which "all those affected by aphasia are entitled to service" and "advocacy efforts should be targeted to those components that are not available in our current healthcare system" (p.41). She adds, "a social approach to treatment requires that each individual's language impairment be viewed within the context of the individual's entire life" and includes attempts to "incorporate the daily activities and life participation events of that individual into the treatment plan from the very beginning" (p.43).

In Chapter 4, "Language and Discourse Deficits Following Prefrontal Cortex Damage," Carol Frattali and Jordan Grafman discuss the anatomy of the prefrontal regions and how damage to these regions can be associated with deficits. They extensively quote Luria's (1970) Traumatic Aphasia, noting that according to Luria,
the special position of language in the organization of behavior is compromised following PFC damage. Accordingly, the prefrontal syndrome is caused largely by disruption of the regulatory role of language on general behavior (Luria, 1970; Luria & Homskaya, 1964). Behavior, in Luria's view, suffers from a lack of the internalized linguistic schema that normally precede and guide any purposeful action and depend on the integrity of the prefrontal cortex. Translated in daily life terms, patients know what they should do and can verbalize it, but cannot always do as they should. Therefore, there is a dissociation of word and deed. This notion suggests that language is impaired not at a strict linguistic level but at a cognitive level of complex, goal-directed and intentionally regulated behavior. (p.55)
The above is consistent with Luria's agreement with Vygotsky's claims about how humans use symbolic tools to master themselves. But, the authors note, "a growing corpus of neuroimaging and lesion studies is beginning to weaken the above claims as being all-inclusive of the nature of language disturbances following PFD damage" (p.55).

This is the fourth book in a row that I've reviewed on aphasia, and I keep describing these books with the term "accessible." Although this collection is not written for a general audience, I found it (mostly) easy to follow, and I learned a lot about how aphasia and related disorders appear and function. As the above quote suggests, this work also has helped me to understand Vygotsky and Luria in different ways. Overall, I recommend this book.

Reading :: Manual of Aphasia Therapy

Manual of Aphasia Therapy
By Nancy Helm-Estabrooks and Martin L. Albert

Here's another (old-ish) book on aphasia therapy. This book is now in its third edition, but I'm reviewing the first edition (1991), which is what UT had in its library.

This book is a good, solid introduction to aphasia rehabilitation, including the neuroanatomy of language, the neuropathology and classification of aphasia, diagnosis, therapy, and impact on family. I found it to be accessible even without any neuropsychology training.

In the first section, the authors break down different types of aphasia along with lesion location (p.21). Like most modern neuropsychologists, these authors caution not to assume that brain functions are localized, but they acknowledge that lesions in specific locations are associated with specific types of aphasia: for instance, Wernicke's aphasia is associated with lesions in the "Posterior third of superior temporal gyrus" (p.21). This means that, just by identifying specific language issues, the therapist can categorize the aphasia and identify where the lesion is without detecting it directly.

The authors go on:
... strong evidence now exists to support each of three apparently unconnected views of the neurology of language: (a) that elements of language can be related to highly focal cerebral centers, (b) that language is organized in the brain in a regional or zone-like pattern, and (c) that every language act involves networks of neurons widely distributed throughout the brain, functioning in series and parallel. (p.32)
They advocate accommodating all three views in a single model in which
multiple, complex overlapping neuronal systems most likely are involved in language processing. These neuronal networks include cortical and subcortical components, some of which are near each other, providing the basis for regional contributions to language, and some of which are more distant, providing the basis for widely distributed, parallel processing of aspects of language. All of the regional and widely distributed networks are multiply interconnected. (p.32)
In this view, the so-called "centers" of language are really "critical 'bottlenecks' for the processing of selected elements of language" (p.33). Notice how this conception seems to accord with Luria's general understanding of cognition as not strongly localized, although it perhaps goes farther away from localization than Luria did (as is common in modern neuropsychology). Overall, an interesting and revealing book. 

Reading :: Language Intervention Strategies in Adult Aphasia, 2ed

Language Intervention Strategies in Adult Aphasia
Edited by Roberta Chapey

I read the second edition of this collection (the link goes to the third edition). This thick book, from 1986, covers several parts: basic and professional considerations; stimulation approaches to therapy; other approaches to therapy; remediation of specific impairments; and remediation of "kindred" or related disorders.

To be honest, I skimmed most of the book. The most interesting chapter for me, and the one I'll examine in this review, is Mark Ylvisaker and Shirley F. Szerkeres' "Management of the Patient with Closed Head Injury" (pp.474-490). I've run into Ylvisaker's work in other places, including a couple of articles and a chapter elsewhere. His approach is Vygotskian, and his focus is on the social environment in which patients recover from injuries. Here, these injuries are characterized as Closed Head Injury (CHI), "in which the primary mechanism of injury is a blunt blow to the head, associated with acceleration/deceleration forces... distinguished from penetrating missile injuries, where the primary damage is focal" (p.474). Elsewhere, Ylvisaker discusses traumatic brain injury (TBI). In both cases, the patients tend to be young men (ex: in motorcycle accidents).

Of interest to me is the focus on compensatory strategies, "simply procedures—sometimes unconventional—that an individual deliberately applies to accomplish a goal" (p.483). These procedures are eventually habituated. They can involve external aids such as logs, alarms, and printed reminders, but they can also involve internal procedures such as mnemonics and structured thinking procedures. Ideal candidates, obviously, "have the metacognitive maturity to think about thinking and other cognitive issues" as well as "adequate attentional resources and ... well-defined neuropsychological strengths on which to base compensatory procedures" (p.483). That is, Ylvisaker and Szerkeres are describing both physical and psychological tools that patients can use to recover functioning—a Vygostkian approach, one that is arguably in a different category from Luria's. They also helpfully include an appendix listing "compensatory strategies for patients with cognitive impairments" (pp.488-490).

Reading :: A Cognitive Neuropsychological Approach to Assessment and Intervention in Aphasia: A clinician's guide

A Cognitive Neuropsychological Approach to Assessment and Intervention in Aphasia: A clinician's guide
By Anne Whitworth, Janet Webster, and David Howard

Although I was worried that this clinician's guide to aphasia would be too technical, I found it to be readable and well organized. Maybe it's all that Luria I've been reading recently.

The authors proffer the cognitive neuropsychology approach, which "first emerged as a coherent discipline in the 1970s as a reaction to the then dominant approach [to diagnosing aphasia] in neuropsychology," the "classical approach," which "sought to characterize the performance of people with aphasia by defining them in terms of their localisation of lesion" (p.3). Recall that Luria argued in Higher Cortical Functions of Man against a hard localization thesis (ex: a "speech center" of the brain, a "writing center," etc.), but Luria did accept a weaker version of the localization thesis—a fact that is not belabored here, but discussed in some of the other neuropsychology books I'll be reviewing soon.

In any case, the authors of this book discuss how to diagnose types of aphasia, identifying variations by different types of impairment. They also discuss therapy approaches, which typically "draw on compensatory strategies (other language and communication skills) to take over those impaired functions" (p.89). I especially appreciated Table 9.1, which lays out different therapy approaches:

  • Reactivation
  • Relearning
  • Brain reorganisation
  • Cognitive-relay
  • Substitution
  • Compensation (p.92)
For our purposes, a couple of these are particularly interesting. The authors describe the cognitive-relay approach's aims this way: "To seek an alternative route or means of performing the language function, i.e. use intact components of the language system to achieve the impaired function through indirect means (Luria, 1970)." The citation is to Luria's Traumatic Aphasia, which I haven't read, but I can see the connection to Luria's other books—especially Higher Cortical Functions of Man and The Man with a Shattered World. Perhaps importantly, the contrast of this approach with the other therapy approaches helps me to think through Miller's argument in Vygotsky in Perspective: that Vygotsky's approach focused on sign mediation and self-mastery, not tool mediation and labor, as later activity theorists did. Luria arguably continued this approach, finding ways to reconfigure cognition to restore functionality. One famous example from Man with a Shattered World: he counsels the patient not to try to spell out words but to write them without thinking. What could not be done with conscious attention could be done via "kinetic melodies."

Compare that approach with another one on the list. Substitution aims "to encourage the adoption of an external prosthesis to promote communication." That is, it turns to physical mediators—tools—distributing part of the job to parts of the environment. One example, although not related to aphasia, might be the approach that Leontiev and Zaporozhets took in Rehabilitation of Hand Function and Leontiev's later works, in which external tools (grids, kymographs) were integrated into the rehabilitation activity, providing an additional feedback loop. Such physical mediators are a common focus in activity theory and, as Miller notes, are typically not well distinguished from psychological mediators (i.e., signs). 

In any case, this book is a solid, generally accessible discussion of how aphasia can be assessed and treated. If you're new to neuropsychology, this might not be the place to start, but it's still pretty readable.


I've been quiet on the blog lately, but I've been reading—books on entrepreneurship, participatory design, Soviet psychology, intuition, executive functioning, and aphasia. Over the next few weeks, I plan to clear out the backlog, so stay tuned.