Biomedical subjects

John F Knutson

Publications and source records attributed to John F Knutson.

9 recordsLinked to original sources

PubMed2006

Schedule-induced electrodermal responding in children.

The current studies were designed to determine whether different intermittent schedules of reinforcement would have a differential effect on the skin conductance responses (SCRs) of children in the 8-12-year-old age range. Results of two experiments indicated that the amplitude of children's SCRs immediately following the occurrence of reinforcement were a function of the schedule of reinforcement, with larger SCRs associated with longer inter-reinforcement intervals. The findings are consistent with the research literature suggesting that long inter-reinforcement intervals can be evocative of aversively motivated emotions, as well as with research on the effects of interstimulus intervals on SCRs. Possible implications for these findings are discussed.

Child↗

PubMed2006

Social and emotional characteristics of adults seeking a cochlear implant and their spouses.

OBJECTIVES: Because past research has shown that benefits of cochlear implantation may include a significant decrease in psychological and emotional difficulties, this study examined whether persons seeking cochlear implants in recent years differed psychologically from those referred in the early 1980s. A second objective was to explore mechanisms by which profound deafness could contribute to psychological and emotional difficulties for implant candidates and their spouses. METHODS: 178 cochlear implant candidates referred from 1981 to 1998 at the University of Iowa Hospitals completed a standard battery of psychological tests and questionnaires. The sample was divided into six 3-year cohorts and compared on standardized measures of psychological and emotional adjustment, and in participation in social and non-social activities. Spouses of implant candidates completed a similar assessment. RESULTS: The sample was characterized by elevations in depression, social introversion, suspiciousness, and social anxiety and loneliness. There were no significant differences among cohorts across time except for an increase in expectations for implant success. Spouses also evidenced elevated levels of psychological distress. Hearing status was associated with significant differences in social activity participation. A paradoxical interaction was found between marital status and deafness. CONCLUSIONS: There was no evidence that the psychological status of implant candidates is changing across time, suggesting continued psychological benefit for persons receiving cochlear implants. Both candidates and their spouses participated in fewer social activities than normal controls. Findings underscore the complex relation between marital status, deafness, and engagement and participation in positive activities.

Adult↗

PubMed2005

Recognition of "real-world" musical excerpts by cochlear implant recipients and normal-hearing adults.

OBJECTIVE: The purposes of this study were (a) to compare recognition of "real-world" music excerpts by postlingually deafened adults using cochlear implants and normal-hearing adults; (b) to compare the performance of cochlear implant recipients using different devices and processing strategies; and (c) to examine the variability among implant recipients in recognition of musical selections in relation to performance on speech perception tests, performance on cognitive tests, and demographic variables. DESIGN: Seventy-nine cochlear implant users and 30 normal-hearing adults were tested on open-set recognition of systematically selected excerpts from musical recordings heard in real life. The recognition accuracy of the two groups was compared for three musical genre: classical, country, and pop. Recognition accuracy was correlated with speech recognition scores, cognitive measures, and demographic measures, including musical background. RESULTS: Cochlear implant recipients were significantly less accurate in recognition of previously familiar (known before hearing loss) musical excerpts than normal-hearing adults (p < 0.001) for all three genre. Implant recipients were most accurate in the recognition of country items and least accurate in the recognition of classical items. There were no significant differences among implant recipients due to implant type (Nucleus, Clarion, or Ineraid), or programming strategy (SPEAK, CIS, or ACE). For cochlear implant recipients, correlations between melody recognition and other measures were moderate to weak in strength; those with statistically significant correlations included age at time of testing (negatively correlated), performance on selected speech perception tests, and the amount of focused music listening following implantation. CONCLUSIONS: Current-day cochlear implants are not effective in transmitting several key structural features (i.e., pitch, harmony, timbral blends) of music essential to open-set recognition of well-known musical selections. Consequently, implant recipients must rely on extracting those musical features most accessible through the implant, such as song lyrics or a characteristic rhythm pattern, to identify the sorts of musical selections heard in everyday life.

Acoustic Stimulation↗

PubMed2005

Care neglect, supervisory neglect, and harsh parenting in the development of children's aggression: a replication and extension.

To understand the effects of neglectful parenting, poor supervision, and punitive parenting in the development of children's aggression, 218 children ages 4 to 8 years who were disadvantaged and their mothers were recruited from two states to develop a sample that was diverse with respect to degree of urbanization and ethnicity. Multimethod and multisource indices of the predictive constructs (Social Disadvantage, Denial of Care Neglect, Supervisory Neglect, and Punitive Discipline) and the criterion construct (Aggression) were used in a test of a theoretical model using structural equation modeling. The results established the role of care neglect, supervisory neglect, and punitive parenting as mediators of the role of social disadvantage in the development of children's aggression, the importance of distinguishing between two subtypes of neglect, and the need to consider the role of discipline in concert with neglect when attempting to understand the parenting in the development of aggression.

Aggression↗

PubMed2004

Disciplinary choices of mothers of deaf children and mothers of normally hearing children.

OBJECTIVE: To assess the disciplinary preferences of mothers of profoundly deaf children and normally hearing children in a test of the hypothesized link between child disabilities and punitive parenting. METHOD: Disciplinary preferences of mothers seeking a cochlear implant for their profoundly deaf child (n=57), mothers not seeking an implant for their deaf child (n=22), and mothers of normally hearing children (n=27) were assessed using an analog task in which subjects select discipline in response to slide images of children engaging in normative or frankly deviant behaviors that are potentially irritating. RESULTS: Results indicated that mothers of children with profound hearing impairments were more likely to select physical discipline in response to depicted child transgressions and more likely to escalate to physical discipline when the depicted child was described as persisting in the transgression. Additionally, escalation was more probable in response to scenes depicting children engaged in dangerous and destructive acts than in rule-violating acts. CONCLUSIONS: Findings were consistent with the hypothesized link between childhood disabilities and child maltreatment as well as the hypothesis that children with disabilities associated with communication problems could be at risk of physical abuse.

Adult↗

PubMed2004

Outcomes and achievement of students who grew up with access to cochlear implants.

OBJECTIVES/HYPOTHESIS: To provide long-term speech perception and production, educational, vocational, and achievement outcome data for pediatric cochlear implant recipients. STUDY DESIGN: This is a retrospective study using consecutive referrals of prelingually, profoundly deaf children at the University of Iowa Hospitals and Clinics. METHODS: Twenty-seven prelingually deaf young adults who received a cochlear implant between the ages of 2 and 12 years participated. Outcome measures included device-use information, perceptual information, reading results for all participants and educational achievement results for 17 of 27 participants, educational placement information/vocational information for all students, as well as a comparison of the child's educational/vocational outcome with that of the parent's educational/vocational outcome. RESULTS: Speech perception and production scores were highly correlated. Achievement test results indicated that scores were within 1 SD from normative data based on hearing individuals. Over 50% of the college-age eligible students enrolled in college. This initial group of implant users had a nonuse rate of 11% in the first 3 years. Eighty-nine percent of the users maintained full-time use for 7 years, and 71% of this group have maintained full-time use to date. CONCLUSIONS: This cohort of cochlear implant users compared favorably with their hearing peers on academic achievement measures. Although there was a wide distribution of educational and vocational outcomes, the children tended to follow the educational/vocational patterns of their parents. As age of implantation decreases, it will be important to compare achievement outcomes of this first generation with those of subsequent generations of cochlear implant users.

Adolescent↗

PubMed2004

The child maltreatment log: a computer-based program for describing research samples.

The Child Maltreatment Log (CML) is a computer-based program designed to record information about children's maltreatment experiences and associated life events. Addressing concerns posed by scientific panels and grant review panels, the CML was designed to improve upon existing instruments to facilitate collaboration among researchers interested in maltreatment. The CML encourages researchers to collect information from multiple sources and informants concerning children's maltreatment experiences. Rather than classifying types of maltreatment a priori, the CML allows researchers to describe children's experiences using objective descriptors pertaining to potential acts of abuse, potential perpetrators, frequency, onset, consequential injuries, and treatment. The CML can be downloaded by interested agencies and groups without charge.

Child↗

PubMed2003

Biology-environment interaction and evocative biology-environment correlation: contributions of harsh discipline and parental psychopathology to problem adolescent behaviors.

Using an adoption paradigm, the Bioecological Model of development proposed by Bronfenbrenner and Ceci in 1994 was tested by concurrently modeling for biology-environment interaction and evocative biology-environment correlation. A sample of 150 adult adoptees (ages, 18-45 years) provided retrospective reports of harsh adoptive parent discipline, which served as the environmental independent variables. Birth parent psychopathology served as the biological predictor. The dependent variables were retrospective adoptee and adoptive parent reports on adolescent aggressive and conduct-disordered behaviors. Finally, adoptees were classified as experiencing contextual environmental risk using the presence of two or more adverse factors in the adoptive home (e.g., adoptive parent psychopathology) as the cutoff. The contextual environment was found to moderate the biological process of evocative biology-environment correlation, providing empirical support for the Bronfenbrenner and Ceci (1994) Bioecological Model.

Adolescent↗

PubMed2002

Performance of cochlear implant recipients with GJB2-related deafness.

Congenital profound hearing loss affects 0.05-0.1% of children and has many causes, some of which are associated with cognitive delay. For prelingually-deafened cochlear implant recipients, the etiology of deafness is usually unknown. Mutations in GJB2 have been established as the most common cause of heritable deafness in the United States. In this report, we identify cochlear implant recipients with GJB2-related deafness and examine the performance of these individuals. Cochlear implant recipients received a battery of perceptive, cognitive, and reading tests. Neither subjects nor examiners knew the etiology of deafness in these individuals. The implant recipients were then examined for mutations in GJB2 using an allele-specific polymerase chain reaction assay, single-strand conformation polymorphism analysis, and direct sequencing. GJB2 mutations were the leading cause of congenital deafness among the cochlear implant recipients screened. Cochlear implant recipients with GJB2-related deafness read within one standard deviation of hearing controls better than other congenitally deaf cochlear implant recipients and non-cochlear implant recipients. Individuals with congenital deafness should be offered GJB2 screening. Positive results establish an etiologic diagnosis and provide prognostic, genetic, and therapeutic information. Effective rehabilitation for profoundly deaf individuals with GJB2-related deafness is possible through cochlear implantation.

Adolescent↗