Howard S. Kirshner

Transient Global Amnesia: Commentary on Trip Gabriel’s First-Person Account

This paper comments on a companion article, a first-person account of an episode of transient global amnesia written by New York Times reporter Trip Gabriel (Gabriel T. 2017. Cogn Behav Neurol. 30:1-4). Mr Gabriel describes having no memories of a cold, rainy day that he had spent on a sailboat competing in two races. The episode may have been triggered by his exposure to water. Afterward, the skipper recalled that Mr Gabriel had functioned fine on the boat, although after returning to shore he needed help finding his car. When he told his wife over the phone that he could not remember where he lived, she got him home and to the hospital. The staff excluded stroke and other causes of amnesia. He felt some awareness after about 9 hours, and the episode ended after about 23 hours. He has been left with a permanent memory gap of 12 hours.The commentary on the case outlines the state of knowledge about transient global amnesia. The diagnosis is well established: a witnessed sudden-onset retrograde and anterograde amnesia lasting <24 hours in a fully conscious person who knows who he/she is and has no other cause for amnesia. Triggers include exposure to water, stress, and sexual intercourse. A normal magnetic resonance imaging scan can help with the often challenging differential diagnosis. Apart from the gap in memory, patients recover fully and only 15% to 20% have recurrences. The underlying pathophysiology has not been explained.

Review of Robinson, The Clinical Neuropsychiatry of Stroke: Cognitive, Behavioral, and Emotional Disorders After Vascular Brain Injury

This volume represents the second edition of a monograph on poststroke cognitive, behavioral, and emotional disorders by a psychiatrist who is widely known as the foremost researcher and authority on the subject of poststroke depression. As such, this updated monograph is very welcome, as it is not often that we have the opportunity to read a singleauthor, uniformly written book by the leading authority in the field. The book has 41 chapters, the great bulk of them dealing with poststroke affective disorders, including 19 chapters on depression, 5 on mania, 5 on anxiety, and 1 chapter each on apathy, pathologic laughter and crying, irritable or aggressive behavior, psychosis, and ‘‘catastrophic reaction.’’ Much shorter shrift is given to the topics of poststroke cognitive disorders, such as right hemisphere syndromes of neglect, anosognosia, and aprosodia. There is little or no discussion of poststroke cognitive deficits such as dementia, aphasia, acalculia, apraxia, agnosia, except as they relate to depression. As such, the book is more accurately a volume on poststroke psychiatric and affective disorders; perhaps the author uses the term ‘‘neuropsychiatry’’ to mean psychiatric manifestations rather than the gamut of cognitive disorders in the stroke patient, but if so the subtitle fails to reflect the primary emphasis on affective disorders. The volume begins with reviews of stroke epidemiology, the history of poststroke cognitive and emotional disorders (again, with an emphasis on depression), brain organization, vascular neuroanatomy of stroke, and depression in general. The brain organization chapter contains some minor terminological and spelling errors, such as ‘‘calcarien,’’ ‘‘saggital,’’ and ‘‘thrombolic’’ occlusion. The author also states that lacunar strokes represent an extension of the atherosclerotic process into smaller arteries; this statement is probably not accurate, given the pathologic differences between atherosclerosis, an intimal deposition of fatty plaques in larger arteries, and the disease of smaller arteries called ‘‘lipohyalinosis’’ or arteriolarsclerosis, a disorder primarily of the media. The chapter on diagnosis of depression shows the first data supporting the association of depression with lesions near the anterior poles, but the scatterplot on page 48 appears to show wide variability, despite the statistical significance of the results. There follow chapters on the phenomenology of depression (very detailed), the natural course of depression, and delayed-onset depression. In chapter 10, the localization of poststroke depression is dealt with in more detail, though the author returns to it in many of the other chapters. Dr Robinson’s research has revealed a close correlation with left more than right hemisphere lesions and anterior more than posterior lesions in poststroke depression, and the data summarized here are authoritative in confirming these associations. He correctly points out, however, that not all studies support these associations, and studies done in patients a few months after onset have shown that right hemisphere stroke patients often develop a delayed depression. Thus, studies done shortly after stroke almost invariably show the association with left, anterior lesions, whereas those done 4 months or more after stroke show much less clearcut associations. My own interpretation of these findings is that right hemisphere stroke patients are more likely to be indifferent or neglectful soon after their strokes, but as the reality of their disabilities gradually becomes obvious, they may be susceptible to a late depression. In addition, right hemisphere patients often seem emotionally flat, and it becomes more difficult to identify depression in such patients. These viewpoints are covered but are little emphasized in this volume. Chapters 11 and 12, on differences between left-handed and righthanded patients and those with bilateral as compared with unilateral lesions, support the associations with left hemisphere and anterior lesions. Subsequent chapters outline the correlations between poststroke depression and impairment in activities of daily living and between depression and cognitive deficits. Antidepressant treatment can improve cognitive function, raising the question of poststroke depression as a cause of reversible dementia. In this section, the neuropharmacology of serotonin binding is discussed with respect to both depression and cognitive function. This discussion seems oversimplified, in terms of the complexity of brain chemistry and pharmacology. Depression also correlates with aphasia, social dysfunction, and even mortality. Chapter 20, on biologic markers, first presents the now disproved dexamethasone suppression test, then data from the growth hormone response to desipramine and the prolactin secretion to d-fenfluramine, neuron-specific enolase, and protein S-100B. No such markers have proved reliable as yet. Chapters 21, 22, and 23 deal with mechanisms, treatment, and prevention of poststroke depression. The emphasis is on reduction in serotonergic transmission after stroke, perhaps because of disruption of thalamocortical circuits. Dr Robinson reviews clinical trials concerning treatment of poststroke depression. In his own studies, nortriptyline has proved superior to fluoxetine or placebo, whereas other studies support the use of other selective serotonin release inhibitor antidepressant drugs, such as citalopram and sertraline. These agents and mirtazapine may prevent poststroke depression. The author goes so far as to recommend on page 278 that ‘‘all patients who have suffered an acute stroke should be placed on antidepressants.’’ Current guidelines do not support such across-the-board treatment, and BOOK REVIEW