2019/12/18 by Michael P. Alexander, Terence W. Picton, Tim Shallice · 1 citation
Medicine · #Traumatic Brain Injury Research
paper · pdf · doi:10.1162/jocn_e_01512
openalex publication_date 2019/12/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
Donald T. Stuss, PhD, OC, OOnt, FRSC, one of the giants of modern neuropsychology, died on September 3, 2019, of complications from pancreatic cancer after a short illness. He was 77 (Figure 1). Don did not follow a normal path to his eventual prominence. He was born in Sudbury, Northern Ontario, in 1941, but spent most of his early life in Kitchener-Waterloo. His father, Nicholas Stuss, had emigrated from Ukraine to Canada in 1921. He and his wife, Ann, owned a small restaurant in Kitchener called “Ann's Diner.”Don did well in school, and his parents encouraged him to study law or medicine. However, Don was rebellious. After he graduated from high school in 1959, he entered a monastery in Mundare, Alberta, run by the Order of St. Basil the Great, part of the Ukrainian Catholic Church. Figure 2 shows a photograph of the young seminarian with his mother in the early 1960s. At the monastery, Don studied and worshipped for 6 years, 3 years of which were under a vow of silence. Toward the end of his training, Don spent a brief time carrying out missionary work in Chad. He enjoyed the contemplative life but was restless. Being Don, he needed to act as well as meditate. Contemplation provided general principles, but these were of little use unless they served to guide behavior. One day just before Don was to become ordained as a priest, a colleague asked him whether he was happy, and he realized that he was not. He later remarked how truly disconcerting the question was.Don left the monastery in 1965 and obtained bachelor's degrees in philosophy from both the University of Ottawa and St. Paul's University in 1967. A formative influence for him during this time was the work of Pierre Teilhard de Chardin, whose book The Phenomenon of Man (1959) considered evolution in theological terms. Teilhard de Chardin proposed that human evolution is part of the more general progress of the universe toward a state of maximum complexity and consciousness. Don found comfort in this combination of the mystical with the scientific.Don subsequently taught high school and coached school football in Peterborough, Kitchener, and Ottawa. These were times of enjoyment and enthusiasm. Always innovative, he once had his football team punt on second down. The opposition was befuddled, and the kicker was able to collect his own kick and run in the winning touchdown. Don married Kaaren Kummer in 1969 and started a family. A son, David, was born in 1973, and a daughter, Leanne, in 1974. Don enjoyed teaching and counseling but realized he did not know enough about how brains and minds developed.We can perhaps locate the beginning of Don's interest in the frontal lobes to this time. Child-centered learning was being advocated, and Don believed in the importance of fixing the attention of the class on what he was trying to teach them. In an attempt to find some intellectual mentor, he came across the Russian psychologist Lev Vygotsky and his book Thinking and Speech (published in 1934, translated 1962). Through him, Don also came to read his collaborator, Alexander Luria, whose books Higher Cortical Functions in Man (1962) and The Working Brain (1973) described how human psychological processes could be localized to different regions of the brain and more specifically how the frontal lobes programmed and regulated these processes.In 1972, he returned to university to study psychology at the University of Ottawa, receiving his MA in 1974 and his PhD in 1976. During this time, he was fascinated by the Human Neurophysiology and Neuroanatomy course that he took in the Medical School. He put together a map of all the anatomical connections of the frontal lobes and located possible psychological functions in each of the connections. Don's diagram was large (about 3 × 5 ft) and extremely intricate. This wondrous map was unfortunately lost, but many of its ideas survive in his later writings.Don then completed a postdoctoral fellowship at the Aphasia Research Center at the Boston Veteran's Medical Center, where he carried out research with Harold Goodglass, Edith Kaplan, and Frank Benson. He returned to Ottawa in 1978, joining the Department of Medicine at the University of Ottawa. He taught and did research in both the School of Medicine and the School of Psychology, rising to Professor in 1989.From this time on, Don's career took an additional new path, that of research leadership, initially at the Rotman Research Institute in Toronto and then, also in Toronto, at the Ontario Brain Institute. We return to these achievements later.His personal research career, which had begun in Ottawa and Boston, really flourished in Toronto. There was one overriding strand in his research from the early 1970s onward—a fascination with the functions of the human prefrontal cortex. Indeed, it is our view that that he made the largest contribution to our understanding of prefrontal cortex of any neuropsychologist since the great pioneers Brenda Milner and Alexander Luria.Don began research not in neuropsychology but in electroencephalography with Roger Broughton and Terry Picton in Ottawa. Don's early research efforts were not always successful. An early project was to study the psychology and physiology of “short-sleepers”—people who only need to sleep for brief periods. One of his subjects was an Indian Swami who claimed that he never had to sleep. Don set him up for an overnight recording to see how his brain waves changed during this prolonged wakefulness. During the night, there were multiple fire alarms, and ultimately, everyone had to evacuate the building. The Swami slept peacefully through all the alarms and was very disconcerted to be woken up for the evacuation.Don's PhD work involved recording the event-related potentials during a task derived from the Weigl and Wisconsin Card Sorting tests of frontal lobe function. Then, during his postdoctoral fellowship in Boston, he studied a large cohort of people who had had frontal leucotomies years earlier. This work with Frank Benson and Edith Kaplan cemented his life-long interest in the impairment patterns, evaluation, and treatment of disorders of the frontal systems. In Ottawa, he continued active research in the psychophysiological measures of cognition and the neuropsychological assessments of patients with frontal lobe lesions but expanded his interests to brain injury and to rehabilitation.One characteristic of patients with traumatic brain injury is that their real-life deficit is far greater than can be easily explained on the basis of the deficits found on neuropsychological tests. Despite their apparent competence, they have difficulty returning to employment and coping with normal life stresses. Don realized that a major factor is variability in performance: Patients do not behave consistently and cannot follow through on tasks. Much of this was likely related to frontal lobe damage. Their relatively normal performance on testing was perhaps due to the neuropsychologist taking on the role of the patient's frontal lobe, making sure that the patient stayed with the tests.Once in Toronto, his research on the neuropsychology of frontal lobe function blossomed in a number of different ways. Initially, he was concerned that there was very little knowledge of the particular areas within frontal cortex where damage could lead to problems on standard clinical frontal lobe tasks such as the Wisconsin Card Sorting Test, Verbal Fluency, Trail-Making Test, and Stroop Test. So, in a series of studies, principally with Michael Alexander, he remedied the problem. The pair related accurate measurements of a variety of aspects of behavior to precise delineations of lesions in a large sample of neurological patients—methods that he continued to use throughout his research career.He was aware, however, that such clinical tests were highly complex, involving many processing subcomponents, and therefore were not very suitable for basic science advances. For that, he believed a set of simpler tasks were needed—and ones that had as far as possible similar stimulus and response requirements. With this philosophy, for over 15 years, Don led an international group of scientists who evaluated an empirically derived model of attention in patients with precisely delineated frontal lesions (Figure 3). Each patient was tested with a battery of simple behavioral tests—the ROtman–Baycrest Battery to Investigate Attention (ROBBIA). The acronym alludes to the Florentine Andrea della Robbia, in whose ceramic sculptures subjects are distinguished from background by means of color and relief. Over the years, ROBBIA led to numerous important findings about how different regions of the frontal lobes contribute to simple attentional behaviors.The first research paper from the test battery showed that the speed of response is controlled by more than one frontal system. The superior medial regions of the frontal lobe are essential for rapid reaction time, either generally or specifically following a warning stimulus. These regions “energize” other supervisory processes. Monitoring of stimulus occurrence and response behavior to enhance the speed of response to upcoming stimuli is, by contrast, sensitive to right lateral lesions of the frontal lobe.His research on frontal functions was far from limited to these major projects. Some intriguing highlights of his research in this period were his description of how the human sense of humor depends upon the normally functioning right frontal lobe and how the frontal lobes are essential to the development of a theory of mind and a sense of self.Much of what happens to cognition as we get older depends on how well frontal systems can maintain performance and even compensate for deteriorating abilities. His research supported the idea that aging is not simply a slowing of general processing. Rather different processes age differently. Some cognitive processes deteriorate quickly after middle age, and some persist well into old age. Cognitive aging is not an escarpment but follows multiple slopes.Don was the quintessential collaborator. Getting people to work together was his forte. As well as the ROBBIA group, Don also collaborated extensively with Sandra Black at Sunnybrook Hospital. In addition, he was instrumental in getting an international group of experts together to set diagnostic criteria for frontotemporal lobar degeneration.Don's research was published in over 200 articles. He also distilled his extraordinarily wide knowledge of the neuropsychology of patients with frontal lobe lesions in a considerable number of review articles and books.Throughout his adult life, Don worked on a theory of how the prefrontal regions of the human brain operate. The following brief summary is based upon his chapter in the Encyclopedia of Clinical Neuropsychology (2017).Don was very early in proposing that there is no single frontal executive or superior attentional system. Rather many different frontal systems interact among themselves and with other regions of the brain in shifting networks. Don was particularly intrigued by five different systems:(i) Superior medial frontal regions are held to activate or “energize” other cognitive functions and in particular supervisory ones. Extensive damage to this region can result in abulia, apathy, or akinetic mutism. Less extensive damage makes patients slow to initiate and sustain mental processes. This slowness is observed in many tests, from reaction time tests to “fluency” generation ones.(ii) Left lateral frontal regions are held to be essential to task setting and planning. This impairment is revealed in many tasks: impaired learning in the early trials of, for instance, serial reaction time or the Wisconsin Card Sorting Test; false positive errors indicating impaired criterion setting in a feature integration task; and false analogous errors in memory recognition in a word list learning task.(iii) Right lateral frontal regions are held to be involved in monitoring performance. Damage here causes deficits on several tasks. There is the lack of the normal decrease in reaction time with longer interstimulus intervals in a so-called “variable foreperiod” task, variability in a timed tapping task, and inconsistency in recall over repeated word lists.(iv) Ventromedial prefrontal (orbitofrontal) cortex is held to be involved in emotional processing and behavioral regulation. Patients with lesions to this area have difficulty in understanding the emotional consequences of their behavior. Tasks sensitive to damage in this region are gambling tasks and the learning (and reversal) of stimulus–reward associations.(v) Frontopolar regions (Brodmann's area 10) are held to be critical for metacognitive aspects of human behavior: autonoetic consciousness, theory of mind, empathy, self-awareness, humor appreciation, and personality. These behaviors require a representation of one's own mental states, beliefs, attitudes, and experiences.Don focused on these five prefrontal systems. The frontal regions are, of course, the seat of many other cerebral processes such as memory access, language generation and more specifically syntax, and working memory. One day, Don hoped to bring them all together.In 1989, Don began an equally important aspect of his career—research leadership. In that year, he accepted the challenge of building a human neuroscience research program at the Baycrest Centre in Toronto by becoming the Founding Director of the Rotman Research Institute (RRI). In this, Don worked closely with the entrepreneur/philanthropist Joseph Rotman, who had raised funds for an institute at the Baycrest Centre to evaluate the effects of aging and aging-related diseases on the human brain. Theirs was a very productive partnership. 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