Cognitive Decline in Childhood or Young Adulthood

Abstract

Childhood dementias are rare, occurring at an incidence rate of 5.6/100,000 (.0056% point prevalence). Many medical disorders can contribute to deterioration in children where a previously acquired skill is lost or negatively compromised. Such diseases would technically be termed a dementia or dementing illness; however, this term is controversial in children. The term's controversy stems from the opposing interactive forces of continued developmental progress in a child and the counter-developmental effect of ongoing or chronic illness. This controversy aside, this chapter discusses illnesses and issues of deterioration in childhood neuropsychological functioning. This is an often neglected issue in Neuropsychology and the interested reader is guided to in-depth descriptions of many of the diseases discussed found in comprehensive texts in pediatric neuropsychology. Cognitive deterioration (i.e., technically a 'dementia') in childhood is difficult to identify and diagnose. The DSM-IV provides for diagnosis of dementia in children, which is based on the same criteria as in adults. Briefly, the diagnosis of dementia requires the presence of significant deterioration in memory and at least one other cognitive domain, which results in difficulty in functioning in social, interpersonal, educational, and/or occupational domains. Deterioration in cognitive and motor skills from a neurodegenerative condition or disease is opposed by neurodevelopmental forces, making it challenging to determine if cognitive and/or motor skills have declined. A diagnosis might have to wait until an adequate evaluation can be obtained. In the interim, the DSM-IV has several diagnoses in which it is recognized that cognitive and motor skills can deteriorate in childhood. Four general patterns of neuropsychological deterioration have been identified in children reflecting the differing affects of the disease/condition and neurodevelopmental forces. 1) Normal development slows, plateaus, and then declines as the disease progresses; 2) Normal cognitive and motor skill development gradually slows without any actual loss of an obtained developmental milestone or cognitive function. The rate of development is slow, and significantly lags behind healthy peers; 3) An acute and rapid decline followed by a cessation of any further cognitive or motor development; 4) An acute and rapid decline followed by a very slow, but otherwise normal, development of cognitive and motor skills. In this chapter, we review some of the more common conditions that can present with cognitive deterioration in childhood or early adulthood. (PsycInfo Database Record (c) 2021 APA, all rights reserved)