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Biomedical subjects

G Woodworth

Publications and source records attributed to G Woodworth.

At least 19 recordsLinked to original sources
PubMed2001

Age-related changes in motor control during articulator visuomotor tracking.

The present study provides normative data on changes in visuomotor control of the oral-facial system across the lifespan. Control of the lower lip, jaw, and larynx (i.e., fundamental frequency) was examined using a nonspeech visuomotor tracking (VMT) task, where subjects move the articulator of interest to track a moving target on an oscilloscope screen. This task examines articulator motor control during movements that are similar to speech but that do not impose linguistic units or the demands of coordinating multiple structures. Accuracy and within- and between-subject variability in tracking performance were measured by cross correlation, gain ratio, phase shift, and target-tracker amplitude difference. Cross-correlation analyses indicated that performance of children (aged 8;2 to 17;0 [years;months]) and older adults (aged 45;1 to 84;3) is poorer than that of younger adults (aged 17;1 to 45;0). Accuracy of movement amplitude tended to increase during development and decline with aging, whereas age did not appear to influence accuracy of temporal parameters in lip and jaw tracking. In contrast, age tended to influence individual variability in temporal but not amplitude parameters. Differences were noted between articulators. The data complement previous studies that considered accuracy and variability of articulator movement during speech. The VMT method and the data provided may be applied to assessment of impairments in the motor speech system and to differential diagnosis of motor speech versus linguistically based disorders.

Adolescent↗
PubMed1999

Driving simulation study: bilateral array multifocal versus bilateral AMO monofocal intraocular lenses.

PURPOSE: To determine whether differences exist in the driving performance of patients with bilateral Array multifocal intraocular lenses (IOLs) and those with bilateral AMO monofocal IOLs under low-contrast environmental conditions. SETTING: The Iowa Driving Simulator at the Center for Computer Aided Design, the University of Iowa, Iowa City, Iowa, USA. METHODS: This prospective study was a test-operator-masked, parallel-group comparison of the driving performance of 33 bilateral multifocal IOL patients and 33 bilateral monofocal IOL patients from the U.S. Array Multifocal study. Driving performance was evaluated under 3 poor visibility conditions (clear weather at night, clear weather at night in the presence of a glare source, and fog). Measures of performance included recognition rates and distances for signs, as well as detection rates, distances, and avoidance behaviors for hazards. Contrast acuity and sensitivity were also measured to evaluate possible correlations with driving performance. RESULTS: No statistically significant differences between the IOL groups were found in 26 of 30 comparisons (86.7%). The monofocal group performed better than the multifocal group in comparisons in which there were statistically significant differences: the percentage of correctly recognized warning signs at night in clear weather (P = .028), sign recognition distances for guide (P = .030) and warning (P = .036) signs in fog, and the detection distance for 1 of 4 hazards (suitcase; P = .026). Correlation coefficients between driving performance and low-contrast acuity and sensitivity were statistically significant; however, they were low and not likely predictive of driving performance. CONCLUSION: Differences between patients with bilateral multifocal IOLs and those with bilateral monofocal IOLs were detected; however, the results indicate no consistent difference in driving performance and safety.

Aged↗
PubMed1998

Electrically evoked compound action potentials of guinea pig and cat: responses to monopolar, monophasic stimulation.

We recorded electrically evoked compound action potentials (EAPs) from guinea pigs and cats using monophasic current pulses delivered by a monopolar intracochlear electrode. By using simple stimuli, we sought results that could shed light on basic excitation properties of the auditory nerve. In these acute experiments, the recording electrode was placed directly on the auditory nerve. Responses to anodic and cathodic stimulus pulses were recorded separately to evaluate stimulus polarity effects. Several polarity-dependent properties were observed. Both EAP morphology and latency were polarity-dependent, with greater latencies for cathodic stimulation. Threshold stimulus level was also polarity-dependent, but in different directions in the two species: cats had lower cathodic thresholds while guinea pigs had lower anodic thresholds. We also observed that the slopes of the EAP amplitude-level functions depended upon stimulus polarity. In most cases where EAP saturation amplitude could be measured, that amplitude was similar for anodic and cathodic stimuli, suggesting that either stimulus polarity can recruit all fibers, or at least a comparable numbers of fibers. The common findings (e.g., EAP morphology and polarity-dependent latency) observed in these two species suggest results that can be extrapolated to responses obtained in humans, while the species-specific findings (e.g., dependence of threshold on polarity) may point to underlying anatomical differences that caution against overgeneralization across species. Some of our observations also bear upon hypotheses of how electrical stimuli may excite different sites on auditory nerve fibers.

Action Potentials↗
PubMed1998

Psychological change over 54 months of cochlear implant use.

OBJECTIVE: To determine the long-term psychological outcome of postlingually deafened adults who received multichannel cochlear implants and to relate the psychological outcome to audiological outcome. DESIGN: Thirty-seven recipients of multichannel cochlear implants who participated in a prospective clinical trial completed psychological assessments before implantation and at regularly scheduled follow-ups through 54 mo of implant use. Standardized measures of affect, social function, and personality were used, and scores on these measures were correlated with asymptotic scores on several audiological measures. RESULTS: Evidence of significant improvement on measures of loneliness, social anxiety, and distress were obtained within a year after implantation and throughout the duration of the follow-up period. For measures of assertiveness and marital satisfaction, improvement was apparent only after long-term implant use. Although favorable changes on the Minnesota Multiphasic Personality Inventory (MMPI) Depression Scale were evidenced only in the initial follow-up period, improvements on the MMPI Paranoia and Social Introversion Scales persisted throughout the 54 mo follow-up. CONCLUSION: Multichannel cochlear implant use is associated with long-term psychological benefit. Correlations between audiological outcome and psychological outcome, however, suggested that the relation between audiological benefit and psychological benefit is not simple.

Adult↗
PubMed1998

Timbral recognition and appraisal by adult cochlear implant users and normal-hearing adults.

The purpose of this study was to examine the appraisal and recognition of timbre (four different musical instruments) by recipients of Clarion cochlear implants (CIS strategy, 75- or 150-microsec pulse widths) and to compare their performance with that of normal-hearing listeners. Twenty-eight Clarion cochlear implant users and 41 normal-hearing listeners were asked to give a subjective assessment of the pleasantness of each instrument using a visual analog scale with anchors of "like very much" to "dislike very much," and to match each sound with a picture of the instrument they believed had produced it. No significant differences were found between the two different pulse widths for either appreciation or recognition; thus, data from the two pulse widths following 12 months of Clarion implant use were collapsed for further analyses. Significant differences in appraisal were found between normal-hearing listeners and implant recipients for two of the four instruments sampled. Normal-hearing adults were able to recognize all of the instruments with significantly greater accuracy than implant recipients. Performance on timbre perception tasks was correlated with speech perception and cognitive tasks.

Adult↗
PubMed1997

Perception of rhythmic and sequential pitch patterns by normally hearing adults and adult cochlear implant users.

OBJECTIVE: This study compares the musical perception of 17 adult recipients of the Nucleus cochlear implant using two different formant extraction processing strategies (F0F1F2 and MPEAK). DESIGN: Over a 12 mo period, participants were alternately switched between two strategies every 3 mo. Performance was evaluated using three measures of rhythmic and sequential pitch perception. RESULTS: Three individuals performed significantly better with the MPEAK strategy on one particular rhythm task, 11 participants performed better with the MPEAK strategy on another rhythm task, and no significant differences were found between the two strategies on a sequential pitch pattern task. CONCLUSIONS: Neither strategy seems clearly superior for perception of either sequential pitch or rhythmic patterns.

Adult↗
PubMed1996

Differences in children's sound production when speaking with a cochlear implant turned on and turned off.

Twenty children who have worn a Cochlear Corporation cochlear implant for an average of 33.6 months participated in a device-on/off experiment. They spoke 14 monosyllabic words three times each after having not worn their cochlear implant speech processors for several hours. They then spoke the same speech sample again with their cochlear implants turned on. The utterances were phonetically transcribed by speech-language pathologists. On average, no difference between speaking conditions on indices of vowel height, vowel place, initial consonant place, initial consonant voicing, or final consonant voicing was found. Comparisons based on a narrow transcription of the speech samples revealed no difference between the two speaking conditions. Children who were more intelligible were no more likely to show a degradation in their speech production in the device-off condition than children who were less intelligible. In the device-on condition, children sometimes nasalized their vowels and inappropriately aspirated their consonants. Their tendency to nasalize vowels and aspirate initial consonants might reflect an attempt to increase proprioceptive feedback, which would provide them with a greater awareness of their speaking behavior.

Child↗
PubMed1995

Adoption study demonstrating two genetic pathways to drug abuse.

BACKGROUND: Studies of adoptees have demonstrated that there are two genetic factors leading to alcohol abuse and/or dependence (abuse/dependence). In addition, environmental factors found in the adoptive family also predict alcohol abuse/dependency independently. One study has found evidence that a similar model of two genetic factors and independent adoptive family factors were involved in drug abuse. Our study was designed to test the hypothesis that genetic factors defined by alcohol abuse/dependency and anti-social personality disorder in biologic parents were etiologic in drug abuse/dependency and that psychiatric problems in adoptive parents were an additional factor associated with drug abuse/dependence. METHODS: A sample of 95 male adoptees, separated at birth from their biologic parents, were followed up as adults to determine their psychiatric diagnosis and their substance use/abuse in a structured interview administered blind to biologic parent diagnoses. A high-risk, case-control design was used wherein half of the adoptees came from biologic parents known to be alcohol abuser/dependent and/or have antisocial personalities (diagnoses from hospital or prison records). These adoptees were matched for age, sex, and adoption agency to a control group of adoptees whose biologic parents were not found in the hospital and prison record search. Adoptive home environment was assessed by structured interviews, including psychiatric assessment of both adoptive parents. RESULTS: Data were analyzed by log-linear modeling, which showed evidence of two genetic pathways to drug abuse/dependency. One pathway went directly from a biologic parent's alcoholism to drug abuse/dependency. The second pathway was more circuitous, and started with anti-social personality disorder in the biologic parent and proceeded through intervening variables of adoptee aggressivity, conduct disorder, antisocial personality disorder, and, eventually, ended in drug abuse/dependency. Environmental factors defined by psychiatric conditions in adoptive families independently predicted increased antisocial personality disorder in the adoptee. Adoptees born of alcohol-abusing mothers showed evidence of fetal alcohol syndrome, but controlling for this did not diminish the evidence for the direct genetic effect between an alcohol-abusing biologic parent and drug abuse/dependency in offspring. CONCLUSIONS: This study confirms the model of two independent genetic factors involved in drug abuse/dependence and previous findings that disturbed adoptive parents are associated with adoptee drug abuse/dependency.

Adolescent↗
PubMed1995

Genetic-environmental interaction in the genesis of aggressivity and conduct disorders.

BACKGROUND: The purpose of this study was to determine the effect of an adverse adoptive home environment on adoptee conduct disorder, adult antisocial behavior, and two measures of aggressivity, all of which are behaviors that contribute to adult antisocial personality disorder and that also are associated with increased vulnerability to drug abuse and/or dependence. METHODS: The study used an adoption paradigm in which adopted offspring who were separated at birth from biologic parents with documented (by prison and hospital records) antisocial personality disorder and/or alcohol abuse or dependence were followed up as adults. They and their adoptive parents were interviewed in person. These adoptees were compared with controls whose biologic background was negative for documented psychopathologic behavior. Subjects were 95 male and 102 female adoptees and their adoptive parents. RESULTS: Multiple regression analysis was used to measure separately genetic and environmental effects. It showed that (1) a biologic background of antisocial personality disorder predicted increased adolescent aggressivity, conduct disorder, and adult antisocial behaviors, and (2) adverse adoptive home environment (defined as adoptive parents who had marital problems, were divorced, were separated, or had anxiety conditions, depression, substance abuse and/or dependence, or legal problems) independently predicted increased adult antisocial behaviors. Adverse adoptive home environment interacted with biologic background of antisocial personality disorder to result in significantly increased aggressivity and conduct disorder in adoptees in the presence of but not in the absence of a biologic background of antisocial personality disorder. CONCLUSIONS: Environmental effects and genetic-environmental interaction account for significant variability in adoptee aggressivity, conduct disorder, and adult antisocial behavior and have important implications for the prevention and intervention of conduct disorder and associated conditions such as substance abuse and aggressivity.

Adoption↗
PubMed1995

Preliminary results with the Clarion cochlear implant in postlingually deaf adults.

A clinical trial of three different multichannel cochlear implants is in progress at The University of Iowa. Fifty postlingually deaf adults participated in a prospective randomized study of the Nucleus implant and the Ineraid device. Subsequently, 23 consecutive postlingually deaf adults have been implanted with the Clarion system. The speech perception performance obtained after 9 months of implant use with all devices was compared. In addition, Clarion patient results at 9 months were compared with long-term (36 months) results from subjects using the other two multichannel implants. Preliminary speech perception scores on the Iowa sentence test (sound-only) and NU-6 words (sound-only) demonstrate that the Clarion subjects, as a group, perform at higher levels than subjects using the other two systems. A wide range of performance is observed with all devices. The continuous interleaved pulsatile strategy of the Clarion device appears to be advantageous for this group of subjects.

Adult↗
PubMed1994

Evidence of heterogeneity of genetic effect in Iowa adoption studies.

This paper describes male adoption studies at the University of Iowa using private and public adoption agencies within the state of Iowa from 1974 to the present time. This research involves four large studies, the first two of which demonstrated significant genetic as well as environmental effects in the etiology of alcoholism as well as significant correlations between adoptee conditions of antisocial personality and alcohol abuse. Findings in the first two studies were similar. However, the third study, using a sample from Catholic-sponsored adoption agencies across the state, failed to show a genetic effect. The final and fourth study was designed in part to look for heterogeneity in the manifestation of a genetic factor from one sample to another in the Iowa studies. This was done by sampling from two agencies, one of which had shown a genetic effect and the other that had not. In this fourth study, the agency that had not shown a genetic effect in the previous study also failed to show an effect, but the agency that had shown a significant genetic effect in the past did demonstrate a significant genetic effect. There were two remaining agencies in the fourth study for which no comparison with past samples could be made. One of these agencies showed a marginally significant genetic effect and the other showed no effect. Statistical analysis of this last study suggested that observed variability in the odds ratio from sample to sample was due to differences in manifestation of the genetic effect.

Adoption↗
PubMed1993

Iowa FICSIT trial: the feasibility of elderly wearing a hip joint protective garment to reduce hip fractures.

Hip fractures exact a heavy toll in the elderly population. While intervention strategies are being investigated to reduce the numbers of geriatric falls and to improve the body's resiliency, the geriatric population remains at risk for the mortality and morbidity associated with fractures. The Iowa FICSIT site is investigating the feasibility of passive protection of the proximal femur through the use of hip pads. The pad is designed to disperse throughout the pad the energy created in a fall. The focus of the Iowa trial is to determine if elderly will wear hip pads for the majority of their waking hours. Thirty subjects are being recruited from each of six elderly populations who are at high risk to fall and at increased risk of injury. To facilitate compliance, the following strategies are utilized: run-in period, graduated implementation, tailoring of wearing times, and self-report of compliance. Outcome measures include compliance rates and injuries sustained during falls.

Accidental Falls↗
PubMed1991

Psychological predictors of audiological outcomes of multichannel cochlear implants: preliminary findings.

The purpose of this research was to determine whether psychological variables were associated with the variability that characterizes the audiological performance of recipients of multichannel cochlear implants. Twenty-nine consecutive recipients of multichannel implants participated in a preoperative psychological assessment and audiological follow-up assessments after 18 months of implant use. Experimental cognitive measures that assess an ability to rapidly detect and respond to features imbedded in sequentially arrayed information accounted for up to 30% of the variance in implant outcome, suggesting the importance of cognitive abilities in implant outcome. Standardized measures of intellectual ability, however, were not predictive of outcome. The Health Opinion Survey, a measure of participatory engagement, was also a significant predictor of audiological outcome. Overall, the results implicated the importance of several specific psychological factors in the audiological outcome of cochlear implants in postlingually deafened adult recipients.

Adult↗
PubMed1991

Psychological change following 18 months of cochlear implant use.

Consecutive recipients of multichannel cochlear implants participated in preimplant as well as 9-month and 18-month psychological evaluations. Before receiving a cochlear implant, psychological tests indicated that the implant recipients were more depressed, suspicious, socially isolated, lonely, and socially anxious than was the general population. After 18 months of implant use, there was a significant reduction in depression, loneliness, social anxiety, social isolation, and suspiciousness. These changes in psychological state did not correlate with improved performance on audiological measures. The data suggest that although cochlear implants can have a positive effect on the emotional and behavioral status of persons with acquired postlingual profound deafness, the psychological outcome of implants is not simply a function of the audiological benefit assessed with standardized speech-based audiological tests.

Cochlear Implants↗
PubMed1990

Genetic and environmental factors in adoptee antisocial personality.

In a sample of 286 adult male adoptees 44 met criteria for antisocial personality (ASP). Two types of biologic parent background were associated with increased incidence of ASP in offspring: those with alcohol problem and those with a criminal conviction or adjudged delinquency. ASP adoptees were also significantly more likely to be alcoholic. Log linear modeling showed that alcohol problems in a biologic parent predicted increased alcohol abuse in the adoptee and that criminality/delinquency in a biologic parent predicted adult adoptee ASP. In the log-linear model two environmental factors significantly increased adoptee ASP: (1) placement in an adoptive home where there was an alcohol problem or antisocial behavior; and (2) placement in a lower socioeconomic home when the adoptee came from a background of criminality/delinquency in a biologic parent. When the adoptee did not have this biologic background socioeconomic level appeared to have little effect on ASP incidence. The results suggest the importance of genetic-environmental interaction in the genesis of adult ASP disorder.

Adoption↗
PubMed1990

Rapid dysplastic transformation of human genital cells by human papillomavirus type 18.

This study delineates differences in biologic activity between human papillomavirus (HPV) types 16 and 18. Human cervical and foreskin epithelial cells were cultured and transfected with recombinant HPV-16 and -18 DNA, resulting in immortalized cell lines. Normal epithelial cells as well as HPV-16 and -18 immortalized cells of both early passages (less than 40 population doublings) and late passages (greater than 180 population doublings) were transplanted in athymic mice. Normal squamous cells formed well-stratified epithelium, while HPV immortalized cells developed either normal-appearing epithelium or typical dysplastic changes. Dysplastic changes were seen in none of the 13 grafts with early-passage HPV-16 cell lines, while 9 of 14 grafts with early-passage HPV-18 cell lines developed dysplasias (P less than 0.0004). These results support previous clinical observations suggesting that HPV-18 may be associated with a more aggressive and rapidly progressive form of cervical neoplasia.

Cell Transformation, Viral↗
PubMed1989

The influence of final-syllable position on the vowel and word duration of deaf talkers.

Hearing talkers produce shorter vowel and word durations in multisyllabic contexts than in monosyllabic contexts. This investigation determined whether a similar effect occurs for deaf talkers, a population often characterized as lacking coarticulation in their speech. Four prelingually deafened adults and two hearing controls produced three sets of word sequences. Each set included a kernel word and six derived forms (e.g., "speed," "speedy," "speeding," etc.). The derived forms were created by adding unstressed and stressed syllables to the kernel form. A spectrographic analysis indicated that the deaf subjects did not always decrease word and vowel durations for the derivatives. Unlike hearing speakers, they often did not reduce vowel segments more than consonant segments. Three explanations are forwarded for the shortening effects. One relates to the implementation of temporal rules, the second concerns the organization imposed upon the articulators to produce speech, and the third suggests a language-independent vocal tract characteristic. The role of auditory information in developing the shortening effects is also considered.

Adult↗