Biomedical subjects

D A Robin

Publications and source records attributed to D A Robin.

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↗

PubMed2001

Motor control in children and adults during a non-speech oral task.

Although decreased accuracy and increased variability of movement is a common developmental finding, the nature of these performance patterns remains poorly understood. The present study examined the accuracy and stability of several aspects of oral motor control. Specifically, we examined the control of absolute timing (temporal parameterization), absolute amplitude (amplitude parameterization), and relative timing and amplitude (generalized motor programs) in children and adults during a lip plus jaw opening and closing task. As was the case with similar reports, we found that children were both less accurate and less stable in their assignment of temporal and amplitude parameters. However, we further found that although children's underlying movement patterns were less accurate than those of adults, children exhibited similar variability in their generalized motor programs. The results are discussed within the framework of a schema model of motor control (Schmidt, 1975) with reference to the strategic allocation of resources during motor learning (e.g., Clark & Robin, 1998).

Adult↗

PubMed2000

Personality change disorder in children and adolescents following traumatic brain injury.

The occurrence of personality change due to traumatic brain injury (PC), and its clinical and neuroimaging correlates were investigated. Ninety-four children, ages 5 through 14 at the time of hospitalization following traumatic brain injury (TBI; severe TBI N = 37; mild-moderate TBI N = 57), were assessed. Standardized psychiatric, adaptive functioning, cognitive functioning, family functioning, family psychiatric history, severity of injury, and neuroimaging assessments were conducted. The Neuropsychiatric Rating Schedule (NPRS) was used to establish a diagnosis of PC. Approximately 40% of consecutively hospitalized severe TBI participants had ongoing persistent PC an average of 2 years postinjury. An additional approximately 20% had a history of a remitted and more transient PC. PC occurred in 5% of mild-moderate TBI but was always transient. Interrater reliability for the diagnosis of PC was good (Kappa = .70). In severe TBI participants, persistent PC was significantly associated with severity of injury, particularly impaired consciousness over 100 hr, adaptive and intellectual functioning decrements, and concurrent diagnosis of secondary attention deficit hyperactivity disorder, but was not significantly related to any psychosocial adversity variables. These findings suggest that PC is a frequent diagnosis following severe TBI in children and adolescents, but is much less common following mild-moderate TBI.

Brain Injury, Chronic↗

PubMed2000

Strength, endurance, and stability of the tongue and hand in Parkinson disease.

Weakness and fatigue in the orofacial system often are presumed to contribute to the dysarthria associated with neuromotor disorders, although previous research findings are equivocal. In this study, tongue strength, endurance, and stability during a sustained submaximal effort were assessed in 16 persons with mild to severe Parkinson disease (PD) and a perceptible speech disorder. The same measures were taken from one hand for comparison. Only tongue endurance was found to be significantly lower in these participants than in neurologically normal control participants matched for sex, age, weight, and height. Analyses of data from a larger sample comprising the present and retrospective data revealed lower-than-normal tongue strength and endurance in participants with PD. No significant correlations were found between tongue strength and endurance, interpause speech rate, articulatory precision, and overall speech defectiveness for the present and previously studied participants with PD, bringing into question the influence of modest degrees of tongue weakness and fatigue on perceptible speech deficits.

Aged↗

PubMed1999

Cognitive outcome in children and adolescents following severe traumatic brain injury: influence of psychosocial, psychiatric, and injury-related variables.

Previous studies of childhood traumatic brain injury (TBI) have emphasized injury-related variables rather than psychiatric or psychosocial factors as correlates of cognitive outcomes. We addressed this concern by recruiting a consecutive series (N = 24) of children age 5 through 14 years who suffered a severe TBI, a matched group who sustained a mild TBI, and a second matched group who sustained an orthopedic injury. Standardized intellectual, memory, psychiatric, family functioning, family psychiatric history, neurological, and neuroimaging assessments were conducted at an average of 2 years following injury. Severe TBI, when compared to mild TBI and orthopedic injury, was associated with significant decrements in intellectual and memory function. A principal components analysis of independent variables that showed significant (p < .05) bivariate correlations with the outcome measures yielded a neuropsychiatric factor encompassing severity of TBI indices and postinjury psychiatric disorders and a psychosocial disadvantage factor. Both factors were independently and significantly related to intellectual and memory function outcome. Postinjury psychiatric disorders added significantly to severity indices and family functioning and family psychiatric history added significantly to socioeconomic status in explaining several specific cognitive outcomes. These results may help to define subgroups of children who will require more intensive services following their injuries.

Adolescent↗

PubMed1998

Adaptive functioning following traumatic brain injury and orthopedic injury: a controlled study.

OBJECTIVE: To study adaptive functioning after severe traumatic brain injury (TBI). DESIGN: Case-control study. SETTING: A university hospital and three regional and four community hospitals. SUBJECTS: A consecutive series (n=24) of children age 5 through 14 years who suffered severe TBI were individually matched to subjects who sustained a mild TBI and to a second group who sustained an orthopedic injury with no evidence of TBI. MAIN OUTCOME MEASURES: Standardized adaptive functioning, intellectual, psychiatric, and neuroimaging assessments were conducted on average 2 years after injury. RESULTS: Severe TBI was associated with significantly (p < .05) lower Vineland Adaptive Behavior composite, communication, and socialization standard scores and lower Child Behavior Checklist parent-rated social competence scores compared with children with orthopedic injury. Severe TBI and mild TBI subjects were significantly (p < .05) more impaired than orthopedic subjects on teacher-rated adaptive function. Family functioning, psychiatric disorder in the child, and IQ were significant variables, explaining between 22% and 47% of the variance in adaptive functioning outcomes. CONCLUSIONS: Severe TBI is associated with significant deficits in child adaptive functioning. This association appears to be mediated by family dysfunction, child psychiatric disorder, and intellectual deficits.

Activities of Daily Living↗

PubMed1998

Predictors of family functioning after traumatic brain injury in children and adolescents.

OBJECTIVE: To assess factors predictive of family outcome in the first 2 years after traumatic brain injury (TBI) in children and adolescents. METHOD: Subjects were children aged 6 to 14 at the time they were hospitalized after TBI. The study used a prospective follow-up design. Assessments of preinjury factors (psychiatric family functioning, and family life events), injury factors (severity of injury), and postinjury factors (coping and development of a psychiatric disorder, never before present, i.e., "novel") were conducted using standard clinical scales. The outcome measure was family function as assessed with standardized family functioning interviews (at 12 and 24 months after TBI) and primary caretaker self-report questionnaires (at 3 and 6 months after TBI). RESULTS: Fifty subjects enrolled, and the analyses focused on 37, 41, 43, and 42 subjects assessed at the 3-, 6-, 12-, and 24-month follow-up evaluations, respectively. The strongest influences on family functioning after childhood TBI are preinjury family functioning, the development of a "novel" psychiatric disorder in the child, and preinjury family life events or stressors. CONCLUSIONS: These data suggest that there are families, identifiable through clinical assessment, at increased risk for family dysfunction after a child's TBI. Early identification and treatment of the child's psychopathology and family dysfunction may attenuate the associated morbidity.

Adaptation, Psychological↗

PubMed1998

Psychiatric disorders in children and adolescents after severe traumatic brain injury: a controlled study.

OBJECTIVE: To study psychiatric and behavioral morbidity associated with severe traumatic brain injury (TBI). METHOD: A consecutive series (n = 24) of children aged 5 through 14 years who suffered a severe TBI were matched to subjects who sustained a mild TBI and to a second matched group who sustained an orthopedic injury with no evidence of TBI. Standardized psychiatric, behavioral, and neuroimaging assessments were conducted on average 2 years after injury. RESULTS: Severe TBI was associated with a significantly higher rate of current "novel" psychiatric disorders (15/24; 63%) compared with children with mild TBI (5/24; 21%) and orthopedic injury (1/24; 4%). Higher effect sizes were evident for child and adolesent self-report of internalizing symptoms rather than externalizing symptoms, for parents' report of overall behavior and internalizing symptoms rather than externalizing symptoms, and for teachers' reports of overall behavior and externalizing symptoms rather than internalizing symptoms. CONCLUSIONS: Severe TBI is a profound risk factor for the development of a psychiatric disorder. Survivors should be assessed for organic personality syndrome, which is the most common psychiatric disorder after this type of injury.

Adolescent↗

PubMed1998

Attention-deficit hyperactivity symptomatology after traumatic brain injury: a prospective study.

OBJECTIVE: To study prospectively the course of attention-deficit hyperactivity (ADH) symptomatology in children and adolescents after traumatic brain injury (TBI). It was hypothesized that ADH symptomatology would be significantly related to severity of injury. METHOD: Subjects were children (n = 50) aged 6 to 14 years at the time they were hospitalized after TBI. The study used a prospective follow-up design. Assessments of preinjury psychiatric, behavioral, socioeconomic, family functioning, and family psychiatric history status were conducted. Severity of injury was assessed by standard clinical scales, and neuroimaging was analyzed. RESULTS: The main finding of this study was that change in ADH symptomatology in the first 2 years after TBI in children and adolescents was significantly related to severity of injury. Overall ADH symptomatology during the study was significantly related to a measure of family dysfunction when family psychiatric history, socioeconomic status, and severity of injury were controlled. CONCLUSION: The presence of a positive "dose-response" relationship between severity of injury and change in ADH symptoms, present from the 3-month assessment, was consistent with an effect directly related to brain damage.

Adolescent↗

PubMed1998

Oppositional defiant disorder symptomatology after traumatic brain injury: a prospective study.

Our goal was to prospectively study the course of oppositional defiant disorder (ODD) symptomatology in children and adolescents in the first 2 years after traumatic brain injury (TBI). Fifty children aged 6 to 14, hospitalized after TBI, were assessed soon after TBI regarding injury severity; preinjury psychiatric, socioeconomic, family functioning, and family psychiatric history status; and neuroimaging was analyzed. ODD symptomatology in the first year after TBI was related to preinjury family function, social class, and preinjury ODD symptomatology. Increased severity of TBI predicted ODD symptomatology 2 years after injury. Change (from before TBI) in ODD symptomatology at 6, 12, and 24 months after TBI was influenced by socioeconomic status. Only at 2 years after injury was severity of injury a predictor of change in ODD symptomatology. The influence of psychosocial factors appears greater than severity of injury in accounting for ODD symptomatology and change in such symptomatology in the first but not the second year after TBI in children and adolescents. This appears related to persistence of new ODD symptomatology after more serious TBI.

Adolescent↗

PubMed1998

Posttraumatic stress symptomatology after childhood traumatic brain injury.

The purpose of this study was to quantify and to identify predictors of posttraumatic stress disorder (PTSD) symptomatology after traumatic brain injury (TBI). Fifty children aged 6 to 14 years, hospitalized after TBI, were assessed soon after TBI regarding injury severity and preinjury psychiatric, socioeconomic, family functioning, and family psychiatric history status; neuroimaging was also analyzed. Psychiatric assessments were repeated 3, 6, 12, and 24 months after TBI. Only 2 of 46 (4%) subjects with at least one follow-up assessment developed PTSD. However, the frequency with which subjects experienced at least one PTSD symptom ranged from 68% in the first 3 months to 12% at 2 years in assessed children. The presence of an internalizing disorder at time of injury followed by greater injury severity were the most consistent predictors of PTSD symptomatology. It is apparent, therefore, that PTSD and subsyndromal posttraumatic stress disturbances occur despite neurogenic amnesia. These problems should be treated, particularly if symptoms persist beyond 3 months.

Adolescent↗

PubMed1998

The effects of varying signal intensity on the perceptual organization of rhythmic auditory patterns.

Cyclic repetitions of temporally structured sequences of sound bursts and gaps are perceived as rhythmic patterns. Some are perceptually unambiguous--the pattern organization is unique; others are perceptually ambiguous--the organization changes. Previous research suggests that the pattern of neuronal adaptation and recovery from adaptation associated with these stimuli determines how listeners perceptually organize the sequences. It follows that variations in the intensity of specific sound elements, which should produce specific changes in the underlying patterns of neuronal activation, should produce predictable changes in the perceptual organization of the sequences. The present study tested this hypothesis by observing the perceptual responses of listeners while varying the intensity of critical elements of unambiguous and ambiguous sequences. The results support the hypothesis in that an unambiguous sequence was made ambiguous and an ambiguous sequence was made less ambiguous. However, the unambiguous sequence did not completely reverse its perceptual organization, nor did the ambiguous sequence become completely unambiguous. The outcome is discussed focusing on the range of intensity increments tested, the type of stimuli used, and the possibility that neurosensory factors may interact with other organizing factors in determining the perceptual organization of rhythmic auditory sequences.

Adolescent↗

PubMed1998

Traumatic brain injury in children and adolescents: psychiatric disorders at one year.

Factors predictive of psychiatric outcome in the second 6 months following traumatic brain injury (TBI) in 43 children and adolescents were assessed prospectively. The outcome measure was the presence of a psychiatric disorder not present before the injury ("novel"). Out of six models tested, four were predictive of novel psychiatric disorder: preinjury family function, family psychiatric history, socioeconomic class/intellectual function, and behavior/adaptive function. Post hoc analyses suggested that preinjury family functioning measured by a structured interview was a significant predictive variable. Severity of injury, when reclassified as severe versus mild/moderate TBI, significantly predicted novel psychiatric disorders. These data suggest that some children, identifiable through clinical assessment, are at increased risk for psychiatric disorders following TBI.

Adolescent↗

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↗

PubMed1997

Traumatic brain injury in children and adolescents: psychiatric disorders in the first three months.

OBJECTIVE: To assess predictive factors of psychiatric outcome in the first 3 months after traumatic brain injury (TBI) in children and adolescents. METHOD: Subjects were children aged 6 to 14 years at the time they were hospitalized after TBI. The study used a prospective follow-up design. Assessments of preinjury psychiatric, behavioral, adaptive functioning, family functioning, and family psychiatric history status were conducted. Severity of injury was assessed by standard clinical scales and neuroimaging was analyzed. The outcome measure was the development of a psychiatric disorder, never before present ("novel") in a subject during the first 3 months after the TBI. RESULTS: Fifty subjects enrolled, and the analyses focused on 37 subjects followed up at 3 months. Increasing severity of injury, presence of a lifetime psychiatric disorder, family psychiatric history, family dysfunction, and lower socioeconomic class/preinjury intellectual function predicted the development of a "novel" psychiatric disorder in the first 3 months of follow-up. CONCLUSIONS: These data suggest that there are children, identifiable through clinical assessment, at increased risk for development of psychiatric disorders in the first 3 months after TBI.

Adolescent↗

PubMed1997

Traumatic brain injury in children and adolescents: psychiatric disorders at two years.

OBJECTIVE: To extend findings regarding predictive factors of psychiatric outcome from the first to the second year after traumatic brain injury (TBI) in children and adolescents. METHOD: Subjects were children aged 6 to 14 years at the time they were hospitalized after TBI. The study used a prospective follow-up design. Assessments of preinjury psychiatric, behavioral, adaptive functioning, family functioning and family psychiatric history status were conducted. Severity of injury was assessed by standard clinical scales and neuroimaging was analyzed. The outcome measure was the presence of a psychiatric disorder, not present before the injury ("novel"), during the second year after TBI. RESULTS: Fifty subjects enrolled, and the analyses focused on 42 subjects followed at 24 months. Severity of injury, preinjury family function, and preinjury lifetime psychiatric history predicted the development of a "novel" psychiatric disorder present in the second year. CONCLUSION: These data suggest that there are children, identifiable through clinical assessment, at increased risk for "novel" psychiatric disorders in the second year after TBI.

Adolescent↗

PubMed1997

Traumatic brain injury in children and adolescents: psychiatric disorders in the second three months.

Psychiatric disorders may be common after traumatic brain injury (TBI) in children, yet there is a death of prospective studies examining this problem. Fifty children aged 6 to 14, hospitalized after TBI, were assessed soon after TBI regarding preinjury psychiatric, behavioral, adaptive, and family functioning, family psychiatric history status and injury severity. The outcome measure was the presence of a "novel" psychiatric disorder (not present before the injury) during the second 3 months after the injury. Forty-two subjects were reassessed at 6 months. Severity of injury, family psychiatric history, and family function predicted a novel psychiatric disorder. Among children suffering a mild/moderate injury, those with preinjury lifetime psychiatric disorders were no longer (as they had been in the first 3 months) at higher risk than those without such a lifetime history. Thus, there appeared to be children, identifiable through clinical assessment, at increased risk for novel psychiatric disorders after TBI.

Adolescent↗

PubMed1996

Sense of effort and the effects of fatigue in the tongue and hand.

Fatigue and increased effort are common symptoms for people with movement disorders and dysarthria, but they are rarely quantified. In an attempt to develop a clinically useful and physiologically meaningful measure of fatigue, we used a task that involves sustaining a target effort level without visual feedback while squeezing a bulb connected to a pressure transducer. In the first experiment, 12 healthy young adults performed the constant-effort task with the tongue and the preferred hand at 3 submaximal levels of effort. The resulting pressure declined over time as a negative exponential function with a nonzero asymptote. In the second experiment, 6 subjects performed the constant-effort task before and after acutely fatiguing the tongue and hand. The rate of pressure decline was significantly greater after fatigue. One possible mechanism for the characteristic negative exponential function is that it reflects a constant descending drive from higher centers in the CNS to the appropriate motoneuron pools. Thus, this technique may elucidate the contribution of central fatigue to normal and disordered speech.

Adolescent↗