During the past decades, the entry of clinical and cognitive neuropsychology into the neurological departments at hospitals has contributed to the differential diagnosis of neurodegenerative diseases leading to dementia. Meanwhile, clinical neuropsychologists are regular members of neurologic, psychiatric, and geriatric departments and are involved in testing patients to objectify subtle cognitive deficits or to help find a probable diagnosis. At the same time, the call for more specific and earlier diagnosis of patients suffering from neurodegenerative diseases is getting louder. Thirty years ago, the task for neuropsychology was limited to argue that there are not only retrieval deficits on the side of the patient and therefore the patient suffers from Alzheimer’s disease and not subcortical dementia. Differential diagnosis did not play a major role, then. Meanwhile the spectrum of neurodegenerative diseases exploded during the following years. For example, Alzheimer’s disease has been divided into one typical variant and three atypical variants.¹  The former frontotemporal lobe dementia or Pick’s disease developed into those starting primarily with aphasia and one starting with behavioural problems.² This differentiation of phenotypes (clinical syndromes) serves to identify specific neuropathological causes and subsequently discover specific treatments. For most of the neurodegenerative diseases, there are no clear-cut biomarkers that would enable a simple and fast diagnosis. As long as such biomarkers are lacking, the clinical assessment is important, and neuropsychology is an essential part of it.

Most chapters of the book, Neuropsychological Tools for Dementia: Differential Diagnosis and Treatment, target the question, how to differentiate with neuropsychological testing, anamnesis and clinical investigation between the various causes for dementias. Based on an extensive review of the literature and many years of experience contributing to the differential diagnosis in clinical routine practice, sensitive tests are proposed and their relation to the neuropathological process are discussed. To increase the practical value of the book, a guideline is added for the assessment answering question like: Which aspect should be part of the anamnesis for different neurodegenerative diseases? What are clinical aspects in the behavior of the patients one should look for? Which tests should be added to a core battery for the suspected disease? Which features contradict a specific clinical diagnosis and should lead to a reconsideration? The steps below, for example, are taken from the guideline chapter on differential diagnosis:  

As one can easily see the guideline does not only make explicit which test should be used to validate a suspected diagnosis of Alzheimer’s disease. It also defines “red flags”, symptoms or impairment, where this suspected diagnosis should be questioned and a different diagnosis should be assumed (with different sensitive tests, which then should be used).

Neuropsychological assessment of neurodegenerative disease not only concerns the task to contribute to the differential diagnosis. It also should offer hints about the prognosis and the functional deficits in activities of daily living. The different book chapters incorporate the findings on the possible prognosis of the patients.³ This is a very important question assessing patients because they want to know if and how fast their impairment might develop from a just measurable deficits to the full-fledged clinical syndrome of dementia. Such knowledge is also important for counselling the relatives and it concerns the permission of the patients to drive a car, but also the question, if the impairment is already such severe that it might be better for the patient to move into a nursery home.⁴ The first chapter of the book tries to synthesize what is known on such social-medical question mainly irrespective of the aetiology of the disease.

A further question the book tries to answer is that of treating the patients. At first sight, this may appear somewhat curious: treatment of neurodegenerative disease that are progressive and cannot be cured? Does that make any sense at all? It was the firm conviction of the author that treatment questions should gain much more importance in neuropsychological research on neurodegenerative diseases. At the end of the day, avoiding or at least delaying the cognitive decline is the major goal of the patients (and not just getting a correct diagnosis). And benefitting the patients is the major goal of the health system. Neuropsychologists should be prepared to contribute to this goal. Rehabilitation and functional training already play a crucial role, for example, for the treatment of patients with Parkinson’s disease, where physiotherapy forms an essential part. Motor and cognitive functions both rely on processes of the same brain. There is no radical difference between them. Thus, there is no reason that only motor functions should show enough neuroplasticity for being a target of rehabilitative effort. Cognitive training and cognitive intervention might also be helpful in patients suffering from neurodegenerative diseases. Fortunately, there is an increasing number of studies documenting an effect of such treatments, and it will be the task of neuropsychologist is to establish them for more and more patients.^5-8

However, the role of neuropsychology is not limited to differential diagnosis and cognitive rehabilitation. Educating the patients about lifestyle changes and how to cope with the increasing impairments by adapting the environment is another important topic of clinical work. Education also involves information about the functional independence of the patients and helps find an optimal time-point for the decision to move into a nursery home. Such decisions are often accompanied by strong emotions on the side of the relatives and professional information about the behaviour of other families may diminish self-reproaches. Unfortunately, research regarding this important question is still very limited. However, some information is already available. Additionally, research on the progression of the disease delaying life-style changes has already reached some global consensus.⁸ Therefore, a second guideline tries to answer the questions concerning psychoeducation and the treatment of the patients, which is most important for the patient. The following Table is taken from the guideline how to treat patients with Parkinson’s disease and cognitive impairment⁹:

Not all parts of the book are written for clinical practical purposes. There are some sections that have a more scientific claim. During the past two decades, neuropsychology diverged into two major branches—research oriented and clinically oriented. At universities, neuropsychology progressively became a part of neuroscience, whereby the main focus of the research concerned functional brain imaging and its different techniques. Clinically oriented colleagues joined cognitive behavioral therapy and looked for adaptation of the patients or the environment to increase the assimilation to the consequence of brain damage. The traditional core of neuropsychology, that is, diagrams explaining cognitive processes and developing cognitive models, has lost its meaning. There is no doubt that the new brain imaging tools enable the collection of new and important information about the implementation of cognitive and physiological processes in the brain that clinical neuropsychology is unable to offer. On the other hand, clinical neuropsychology is concerned with patients suffering from specific disease or brain lesions (and not with brains or brain areas). Understanding the problems of the patients and treating them presupposes a clinical level of research, which was the strength of classical neuropsychology. Therefore, the last section of each chapter is dedicated to questions of cognitive neuropsychology, the level of thinking, which permits the integration of neuroscientific and clinical knowledge to serve diagnosis and treatment on the patient’s level.

Neuropsychological Tools for Dementia: Differential Diagnosis and Treatment is based on years of clinical routine practice with patients as well as on years of teaching students and clinical colleagues in cognitive neuropsychology of the dementias. This interplay dominated the motivation and the outline. In the best-case scenario, it helps to slightly improve the fate of the patients suffering not only from a severe disease that cannot be cured but also from uncertainties concerning how to delay the progress and how to prepare for a future with increasing loss of functional independence.

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References

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