The Amnesias: A Clinical Textbook of Memory Disorders

One of the most frequent disorders observed after acquired brain injury is memory disorder. Proper assessment and diagnosis is a requirement before starting neuropsychological rehabilitation, and clinicians normally base their decisions on neuropsychological assessment (NA).  NA is very important in making a sound clinical diagnosis, but it is not the clinical diagnosis.

The Amnesias : A Clinical Textbook of Memory Disorders (Hardcover) 
by Andrew C. Papanicolaou 
Hardcover: 336 pages 
Publisher: Oxford University Press, USA (November 24, 2005) 
Language: English 
ISBN: 0195172450 
Dimensions: 9.5 x 6.5 x 0.8 inches 
Price: $57.50 

There is also life before and after NA. This is to say, neurologists, neuropsychologists, neurorehabilitationists and psychiatrists have to recover their passion for thorough clinical explorations of patients.  A good clinical exploration of an amnestic patient requires clinicians to have ample knowledge on cognition and the theory of normal memory, as well as proper descriptions of amnestic syndromes and an understanding of the pathophysiology and their courses. Without this, they are unable to provide the differential diagnosis, prognosis and possible treatments to follow. Of course, a good clinician has to have sufficient hands-on experience with patients in real practice and in the real world. The book “The Amnesias: A Clinical Textbook of Memory Disorders”, by A.C. Papanicolaou, is an excellent resource to accomplish this endeavor.

Memory is probably one of the best studied complex cognitive functions found in neuropsychological literature. Excellent textbooks and research articles on memory in the brain have been published and continue to be published, but difficulties exist in integrating the clinical and applied features of memory disorders with the basic findings published in the literature. This may be due to our uncertainty of whether the damaged brain functions like a healthy brain. It is therefore unclear whether findings on cerebral functioning during normal memory processes can be applied to the damaged brain. When brain injury is present, brain circuitry changes and the mechanisms of remembering and forgetting appear to convert into different circuitry. As clinicians, we learn from basic studies on normal memory what is “not” normal in patients, but we have learned less about “how” the brain really functions in amnesia patients with brain injury.

The book “The Amnesias: A Clinical Textbook of Memory Disorders” is addressed to clinicians and it possesses a strong conceptual and theoretical base. It is a book on memory, on cerebral functioning and on the decay of the mechanisms and processes of memory: the amnesias.

Every good book should begin by defining and clarifying the subject under study, which in this case is amnesia, and this book does so. The first chapter, “Phenomena and construct”, is written by Andrew C. Papanicolaou. The author writes clearly and extensively on the confusion which exists in ordinary speech and in technical discourse regarding the term memory. He points out that when we use the term memory, we are referring to any of at least six distinct possibilities: a function, brain structures, neural codes, experiences, a category label or a system. These distinctions are expressed with elegance, intelligence and clarity.  An explanation is given as to the common and diverse aspects of aphasia, agnosia and apraxia, of mnemonic and amnesic phenomena, of the varieties of episodic and semantic memories and of implicit memories and their groupings.  Autobiographical memories are explained in the context of episodic, semantic and implicit memories. The author also provides ample discussions on constituent functions of the primary system, immediate or short term memory, working memory functions and retrieval, before moving on to study the secondary memory system and its constituent functions. He ends with an overview of the syndromes of amnesia.  A compact, clear chapter, it is essential reading for those who must understand the phenomenon of memory in their day to day clinical practice.

The second Chapter, whose first author is Pramod Dash, centers on the “Putative brain mechanisms of the various memory functions”. The authors study the gross anatomical unit which constitutes the mechanisms of basic primary and secondary memory functions, as well as microscopic biochemical events and the influence of hormones and drugs on memory systems. They explain the brain structures involved in encoding and retrieval as well as in consolidation. They also discuss the mechanisms of the secondary memory system, the long-term storage of memory traces, the role of the thalamus in all memory functions and the relationships between memory and emotions. An important part of the chapter clearly explains how neurotransmitter systems are involved in memory and the effect of drugs, hormones and stress on these systems.

Chapter three, whose first author is Alexandra Economou, is entitled “Age-related memory decline”. It begins by defining normal or successful aging as the absence of specific diagnostic or medical conditions, with intact physical and cognitive functioning, and then establishes the symptoms of memory difficulties in the elderly. The section dedicated to the differential diagnosis between dementia and normal memory problems related to aging includes two descriptive cases that follow age-related changes in the brain. The chapter ends with responses to four questions regarding age-related memory decline.

The fourth Chapter, by Alexandra Economou and colleagues, focuses on “Amnesias associated with the dementias” and explains how dementia-related amnesic syndromes vary not only in the neuroanatomical location of the damage but also in the progression and spreading of the degeneration. To illustrate the different syndromes, six different cases are included; mild Alzheimer´s disease, strategic thalamic dementia, temporal variant frontotemporal dementia, subcortical ischemic vascular dementia, Parkinson´s disease dementia, and frontal variant frontotemporal dementia. The chapter finalizes with a discussion on epidemiology and predisposing factors, prognosis and treatment and conclusions and speculations.

Chapter five, by Papanicolaou and colleagues, is dedicated to “semantic amnesia”, what is considered the loss or the inaccessibility of facts and concepts that have been part of one’s store of knowledge. Three clinical cases illustrate the syndrome and special emphasis is given to differential diagnosis, pathophysiology and prognosis and treatment.

“Limbic amnesia” is the title of Chapter six, authored by Rebecca Billingsly-Marshall and colleagues. Damage to the limbic system results in anterograde and retrograde deficits in explicit memory, and the most consistent symptom in patients is anterograde episodic amnesia. The authors explain how to test and establish the symptoms (medial temporal lobe amnesia, diencephalic amnesia, basal forebrain amnesia), and also discuss precipitating factors, differential diagnosis, pathophysiology and prognosis and treatment.

“Traumatic amnesia”, by Maria Kosmidis and colleagues, is the title of Chapter seven, which centers on memory disorders associated with a traumatic brain injury. The symptoms are established throughout the study of three cases found in the literature. The types of memories affected by TBI and the neuropsychiatric sequelae of TBI are discussed, as are precipitating factors, pathophysiology and prognosis and treatment.  

Simos and Papanicolaou have written Chapter 8, entitled “Transient global amnesia”, in which they describe an apparently benign disorder of memory that has a sudden and disconcerting onset, is resolved almost entirely within a few hours and rarely last more than 24 hours. Three cases from the literature are shown and a thorough discussion of definition and clinical symptoms is given. As in other chapters, precipitating factors, differential diagnosis, pathophysiology and prognosis and treatment are well discussed.

In Chapter nine, authors Papanicolaou and Kosmidis grapple with a condition that is difficult to diagnose: the “Transient epileptic amnesia”. It is characterized by transient episodes of amnesia, which take place while the patient behaves normally. Clinical features and differential diagnosis are discussed.

The tenth Chapter, “Electroconvulsive therapy-induced Amnesia”, also written by Papanicolaou and Kosmidis, describes an impairment of memory that appears after ECT, which is characterized by a disruption of the process of consolidation of newly learned information during induced seizures.

In Chapter eleven, authors Savvidou, Bozikas, and Papanicolaou discuss “Psychogenic amnesia”. Three characteristics are well described: that it is exclusively retrograde in nature, is highly selective, and has deficits which are reversible. Four clinical cases are presented and different controversial treatments are described.

Papanicolaou, in the twelfth and final Chapter, has written “Notes for a theory of memory”, with the intention of providing a theoretical framework within the reasonable working hypotheses that are widely accepted today.  The book ends with an “Appendix of Neuropsychological Tests” written by Lorig, and an extensive number of references covering current and significant literature on memory and amnesias.

In general, it is important to note that despite being a collective effort, the book is also the work of one author in particular. Papanicolaou participated in every chapter, and gave each one the same structure, which gives special coherence to the book as a whole.

Overall, the book is well-written with clear concepts and up-to-date research. Clinicians should include it in their resource library as a practical handbook which covers all the possible syndromes of amnesia to be found in any neurological or even psychological patient. Similarly, it is an indispensable resource for university teaching on amnesia and its related disorders; it is equally indispensable for any neuropsychologist, neurologist, neurorehabilitationist or neuropsychiatrist. Books such as this are also particularly important for memory researchers, given its numerous suggestions. It is a book I highly recommend.

Prof. Jose Leon-Carrion,Ph.D
Human Neuropsychology Lab. University of Seville. Andalucia, Spain
Center for Brain Inury Rehabilitation (CRECER), Sevilla. Andalucia, Spain.