Emergent symbolic relations in speakers and nonspeakers.

Eight adults with developmental disabilities and four typically developing preschool children participated in an experiment studying emergent stimulus-stimulus relations after match-to-sample instruction. Participants were taught to match lexigrams (arbitrary graphic stimuli) to objects. Each object was functionally related to another object in the teaching set. For example, brush and comb were members of the teaching set. Most participants were able to select objects when the objects were named in pretests. Postteaching probes assessed emergent relations between spoken names and lexigrams. In addition, we included probes to detect emergent relations between related lexigrams. That is, would participants select the lexigram for comb when the experimenter displayed the lexigram for brush (without explicit teaching)? Two preschool children and five adults with developmental disabilities showed emergent relations between lexigrams and spoken words. However, only two preschool children showed the emergent lexigram to related lexigram relations.

Communication forms and functions of children and adults with severe mental retardation in community and institutional settings.

The forms and functions of expressive communication produced by 84 individuals with severe mental retardation were assessed, using a structured communication sampling procedure. Symbolic communication acts were produced by 39 participants, and 27 of these symbolic communicators produced one or more multiword/multisymbol utterances. Of the remaining participants, 38 produced intentional but nonsymbolic communication acts; 7 were not observed to produce any intentional communication. For all participants who produced intentional communication, there were significantly more imperative than declarative communication acts. Significant differences in the frequencies and functions of communication acts produced by these participants were associated with differences in their communication levels (contact gesture, distal gesture, or symbolic), age (child vs. adult), and residential status (community home vs. large facility).

Simultaneous and delayed matching to sample in gesture users and speakers with mental retardation.

Sixty-eight participants with severe mental retardation participated in a study of representational matching to sample. Participants were asked to match objects to identical objects, line drawings, miniature objects (icons), pantomimes, and spoken names. Participants who were successful in these matching tasks also experienced delayed matching tasks. Participants differed in their expressive communication and comparisons were made between symbolic (speaking) individuals, distal gesture users, and contact gesture users. Contact gesture users were significantly worse on identical matching to sample tasks than other participants. Mean scores on matching objects to line drawings were significantly better than mean scores on other matching tasks. In delayed matching, however, scores for matching objects to spoken names were significantly better than other tasks. The implications of these results for learning to use an augmentative communication device are discussed.

Genetic amniocentesis following multifetal pregnancy reduction does not increase the risk of pregnancy loss.

A collaborative, retrospective study of patients who had undergone multifetal pregnancy reduction (MFPR) to twins and subsequent genetic amniocentesis was performed to determine if amniocentesis increased the risk of pregnancy loss. Seventy-nine patients from three centres underwent MFPR and subsequent amniocentesis. The pregnancy loss rate was 5.06 per cent in this group. In comparison, the loss rate from a control collaborative series of patients who underwent MFPR only was 11.19 per cent, which was not statistically different. Thus, it appears that amniocentesis following MFPR is unlikely to increase the pregnancy loss rate.

In utero allogeneic hematopoietic stem cell transplantation to induce tolerance.

We studied the efficacy of in utero hematopoietic stem cell transplantation and the ability of such transplantation to induce tolerance in a fetal normal mouse allogeneic model. In 9 of the 162 surviving recipients (5.6%), cells of donor origin were detected after birth. The highest engraftment rate was achieved by transplanting fetal liver cells in a relatively high dose (> 10(6) cells/fetal gram). Skin grafting was performed to determine the presence of prenatally induced tolerance. Only those mice which showed evidence of chimerism became tolerant to skin derived from the prenatal donor's strain while remaining competent to reject a skin transplant from a third strain. Tolerant mice could have significant chimerism reestablished by utilizing monoclonal antibody specific for the recipient H-2 antigen as conditioning for IV fetal stem cell retransplantation.

Reported communication abilities of individuals with severe mental retardation.

Little is known about the distribution of communication skills among individuals with severe mental retardation. The present study was designed to obtain basic descriptive information about the reported expressive communication status and other associated sensory and behavioral characteristics of four representative samples of this overall population. These samples include both children and adults and individuals living in large residential facilities as well as those living at home or in smaller, more natural community environments. Results of this study, based on completed questionnaires for 211 subjects, revealed a wide range of communication abilities in this population, with a significantly larger percentage of adults than children communicating at symbolic levels.

Initiation and repair of intentional communication acts by adults with severe to profound cognitive disabilities.

This study assessed the communication initiation and repair behaviors of 28 individuals with severe to profound mental retardation in a variety of experimental conditions. All of these individuals communicated through nonsymbolic gestures. The experimental procedures were devised to simulate the conditions that typically evoke two different types of initiations: comments and requests. Each subject initiation was followed by an experimenter response that indicated a communication breakdown to determine if and how these subjects would attempt to repair such breakdowns. Different indicators of communication breakdown were systematically varied in these scripted interactions, including explicit requests for repair (verbal and gestural) and implicit requests for repair (failure to respond or inappropriate response to the subject's communication act). All subjects initiated at least one communication act, and all but three subjects repaired at least one communication act following a breakdown. Significantly more subjects initiated protoimperative than protodeclarative communication acts, despite equal opportunities for both types of acts. Across all conditions, additions were observed to occur significantly less often than recasts or repetitions. There were no significant differences in the number of subjects repairing communication following the different types of communication breakdown.

Detection of viral deoxyribonucleic acid in the amniotic fluid of low-risk pregnancies by polymerase chain reaction.

OBJECTIVE: The purpose of this study was to determine whether viral deoxyribonucleic acid is detectable in the amniotic fluid of pregnancies at low risk for fetal viral infection. STUDY DESIGN: Amniotic fluid samples were prospectively collected from 277 patients. Selected primer pairs amplified deoxyribonucleic acid sequences unique to adenovirus, cytomegalovirus, herpes simplex virus, and parvovirus. Amplified deoxyribonucleic acid was detected by gel electrophoresis. Sensitivity of the adenovirus, cytomegalovirus, and herpes virus primers were determined by serial dilution of 10(3) PFU/ml controls. RESULTS: Of the 277 extracted samples, 243 had detectable deoxyribonucleic acid. None of these samples had detectable viral deoxyribonucleic acid by polymerase chain reaction. The sensitivity of the adenovirus primer pairs was 10(-3) PFU/ml, cytomegalovirus 10(-2) PFU/ml, and herpes simplex virus 10(-1) PFU/ml. CONCLUSION: This study did not detect viral deoxyribonucleic acid in a low-risk population, supporting the clinical significance of detecting viral deoxyribonucleic acid in pregnancies at risk for infection.

Communication profiles of two types of gesture using nonverbal persons with severe to profound mental retardation.

A structured communication sampling procedure was used to measure the form and function characteristics of intentional communication acts produced by nonverbal adults with severe mental retardation. Four "contact" subjects (who communicated only with contact gestures) and 4 "distal" subjects (who used distal as well as contact gestures) participated in this study. All subjects produced communication acts that were coded as initiations, and all subjects produced protoimperative-type communication acts. However, contact subjects produced no protodeclarative-type communication acts, whereas all distal subjects produced some protodeclaratives. Distal subjects also produced significantly more repair/recast acts than did contact subjects. Other findings included a tendency for distal subjects to communicate at a higher rate, to initiate more communication acts, and to produce more accompanying wordlike vocalizations than contact subjects. These results are discussed in light of Werner and Kaplan's (1984) concept of distancing as central to symbolization. Implications for future research and for clinical practice are also discussed.

Verbal information gathering strategies: the child's use of language to acquire language.

Recent investigations suggest that normally developing infants are active participants in a language-transmission partnership with the mature speakers in their environments. In a recent paper, (Snyder, McLean, 1977) we noted that available data suggest several specific language acquisition strategies exhibited by children in these interactions. While the earlier paper focused on a set of posited nonverbal strategies, this sequel focuses on two broad types of early verbal behavior that function as effective strategies for the language-learning child. These posited verbal acquisition strategies are referred to as selective imitation and metalinguistic utterance production. The conflicting theory and data on the role of early verbal imitation are reviewed, and it is concluded that selective imitation is most functional at specific stages of the language acquisition process. A hierarchy of metalinguistic utterance types is suggested, ranging from those reflecting the highest apparent intentionality (that is, interrogative utterances) to those reflecting the least (referred to as evocative utterances). Suggestions for future research are offered and implications for language intervention are discussed.