Retrogenesis is the process by which degenerative mechanisms reverse the order of acquisition in normal development. Alzheimer's disease (AD) and related conditions in the senium have long been noted to resemble "a return to childhood" Previously, we noted that the functional stages of AD precisely and remarkably recapitulated the acquisition of the same functional landmarks in normal human development. Subsequent work indicated that this developmental recapitulation also applied to the cognitive and related symptoms in AD. Remarkably, further investigations revealed that the same neurologic "infantile" reflexes, which mark the emergence from infancy in normal development, are equally robust indicators of corresponding stages in AD. Neuropathologic and biomolecular mechanisms for these retrogenic processes are now evident. For example, the pattern of myelin loss in AD appears to mirror the pattern of myelin acquisition in normal development. Also, recent findings indicate that mitogenic factors become reactivated in AD, and, consequently, the most actively "growing" brain regions are the most vulnerable. Because of this robust retrogenic process, the stages of AD can be translated into corresponding developmental ages (DAs). These DAs can account for the overall management and care needs of AD patients. A science of AD management can be formulated on the basis of the DA of the Alzheimer's patient, taking into consideration differences of AD from normal development as well as homologies.

Data from clinical, electrophysiologic, neurophysiologic, neuroimaging and neuropathologic sources indicates that the progression of brain aging and Alzheimer's disease (AD) deterioration proceeds inversely to human ontogenic acquisition patterns. A word for this process of degenerative developmental recapitulation, "retrogenesis", has been proposed. These retrogenic processes provide new insights into the pathologic mechanism of AD deterioration. An understanding of retrogenic phenonmena can also result in insights into the applicability of retrogenic pathologic mechanisms for non-AD dementing disorders. Management strategies based upon retrogenesis have recently been proposed. Retrogenic pathophysiology also points to previously unexplored pharmacologic approaches to dementia prevention and treatment.

Background: General relationships between dotage and infancy and childhood have been acknowledged for more than two millennia. Recent findings indicate precise relationships between functional, praxic, and feeding changes in the course of the degenerative dementia of Alzheimer's disease (AD) and inverse corresponding developmental sequences. Similar inverse relationships between AD and human development can be described for cognition and language skills; for physiologic measures of electroencephalographic activity, brain glucose metabolism, and developmental neurologic reflex changes; and for the neuropathologic and neuroanatomic progression of these processes. In AD, these processes may be termed “retrogenesis.” The relevance of the retrogenesis model for AD management is explored. Method: The functional stages of AD can be translated into developmental age equivalents that can be utilized to explicate observed changes in the disease. Results: The retrogenesis-based developmental age model can usefully inform an understanding of the general care needs, emotional and behavioral changes, and activity needs of the AD patient. This model must be amended by necessary caveats regarding physical differences, variations in age-associated pathology, differences in social and societal reactions, and differences in background between AD patients and their developmental age “peers.” Conclusions: Knowledge of retrogenesis and the developmental age of the AD patients can form a nidus for the development of a nascent science of disease management. Such a science must ultimately incorporate not only appropriate caveats but also relevant universal human needs, such as those for dignity, love, and movement.

As a result of the neuropathologic process of Alzheimer's disease (AD), significant changes occur in neuromotor function (e.g., paratonia and compulsive grasping). These changes become manifest in the moderately severe stage of AD, when patients begin to require ongoing assistance with activities of daily life (ADL), and they are prominent in the severe stage of AD, when patients are continuously dependent on a caregiver. Patients in these stages often display behavioral disturbances during care activities. These disturbing behaviors result not only from cognitive impairment, but also from a patient's physical inability to cooperate with the caregiver. When care management strategies take into account the characteristic physical restrictions resulting from the neuromotor changes that accompany advanced AD, the caregiving process may be significantly facilitated.

Joint contractures are very common in the severe stages of Alzheimer's disease. More than a quarter of a million institutionalized residents in US nursing homes are likely to be afflicted by this potentially painful and disfiguring condition. Possible pathophysiology and contributing factors and possible means of intervention for this major source of disability are discussed.