Language recovery following isolation for severe combined immunodeficiency disease

The evolution of the critical period for language acquisition

Evidence suggests that there is a critical, or at least a sensitive, period for language acquisition, which ends around puberty. The existence of this period is explained by an evolutionary model which assumes that (a) linguistic ability is in principle (if not in practice) measurable, and (b) the amount of language controlled by an individual conferred selective advantage on it. In this model, the language faculty is seen as adaptive, favoured by natural selection, while the critical period for language acquisition itself is not an adaptation, but arises from the interplay of genetic factors influencing life-history characters in relation to language acquisition. The evolutionary model is implemented on a computer and simulations of populations evolving under various plausible, if idealized, conditions result in clear critical period effects, which end around puberty.

Children reared in a reverse isolation environment: effects on cognitive and emotional development

Cognitive and emotional aspects of development in four infants reared in a reverse isolation environment because of congenital severe combined immunodeficiency disease were studied by psychological test performance and formal observation. The children were studied while they were inpatients and following their discharge after successful medical treatment was accomplished. Treatment time in reverse isolation varied from 10 to 52 months. Deficient self-generated activity, including motor and motor-based cognitive skills such as expressive language, were observed in two of the four children. Deficits were also observed to be at least moderately reversible either upon discharge or in relation to an inpatient intervention program. Case material is discussed with reference to severe disruption of oral feeding experience, quality of parental involvement, and sensory isolation inherent in the environment.

Developmental abnormalities in infants and children with acquired immune deficiency syndrome (AIDS) and AIDS-related complex

Children with acquired immune deficiency syndrome (AIDS) display two types of clinical picture: a full-blown AIDS characterized by the presence of opportunistic infections and/or Kaposi's sarcoma and a prodromal stage now identified as AIDS-related complex (ARC). Neurological complications have been identified in infants and children with the disease. This paper discusses the developmental abnormalities in 16 pediatric patients, seven with AIDS and nine with ARC, ranging in age from six months to six years. In all cases, the mothers of these children either had ARC, AIDS and/or used intravenous drugs. Developmental histories showed delayed acquisition of milestones in most children following the diagnosis of AIDS or ARC, with delayed motor milestones consistently noted in both groups. Several children with AIDS actually lost milestones as their illness progressed; this has not occurred in the ARC group. Psychometric testing revealed more severe cognitive dysfunction in the group with AIDS. Involvement of the central nervous system was documented clinically, radiologically, and/or electrophysiologically in all patients with AIDS. In the ARC group the course of the illness has shown greater variability. Medical and social factors that may contribute to the developmental abnormalities are discussed.