The scaling of postural adjustments during bimanual load-lifting in traumatic brain-injured adults

Previous postural studies of traumatic brain injury (TBI) patients have been limited to identifying deficits in static and quasi-dynamic postural control tasks such as weight shifting. In this study, we examined whether or not patients with TBI are able to scale adequately their postural adjustments during the performance of the dynamic task of bimanual load-lifting. An age matched group of healthy adults served as controls. We used the Tetrax posturography system that calculates a stability score (ST) based on fluctuations in vertical ground reaction forces, normalized for body weight. During quiet standing, the ST scores of the TBI group were significantly higher than the control group. Forward weight shift and percentage change in the vertical ground reaction forces (lift postural adjustment (LPA) and post-lift postural adjustment (PLPA) scores) linearly increased with increasing load weight in both healthy and TBI subjects. Group differences were found in the magnitude of forward weight shift but not in the relative increase of the LPA and PLPA scores during the lifting and post-lifting phases respectively. The forward weight shift of the TBI group was lower-than-normal and asymmetrical--there was significantly less forward weight shift on the more affected than on the less affected limb. In addition, a significant amplitude coupling was found between the scaling of the weight shift of the heel and forefoot of each limb. However, no coupling was found between the weight shift amplitudes of homologous parts of both limbs in the TBI group. The results showed that scaling based on prior experience was preserved in the TBI group, though some TBI subjects demonstrated absent scaling in either the more affected or less affected heel or forefoot. The differences between the normal and TBI groups in postural adjustments are not necessarily a sign of pathology; rather they may represent a deliberate choice of the central nervous system to counteract predictable disturbances.     

Depression After Traumatic Brain Injury: A Review of Evidence for Clinical Heterogeneity

Depression represents a major source of disability among individuals who have suffered a traumatic brain injury (TBI), with estimates of prevalence in this population ranging over 50%. In comparison with other sequelae of TBI, depression is often poorly conceptualized and treated among acute care and rehabilitation professionals. One reason for this is the lack of clear etiological models for the development of depression following TBI. This paper argues that post-TBI depression actually represents a heterogeneous category, with multiple etiologic pathways and clinical implications. The literature in this area is reviewed, with an emphasis on an appreciation of the diversity within this clinical population. Conclusions focus on suggestions for differential diagnosis and treatment options.     

Activational and organizational effects of estradiol on male behavioral neuroendocrine function

Evidence is reviewed that establishes an essential role for estradiol, synthesized locally via aromatization of testosterone in the adult as well as the developing male nervous system of rats, ferrets, and mice, in both the organization and adult activation of neural circuits that control appetitive as well as consummatory components of masculine sexual behavior. Evidence is also reviewed suggesting that perinatal estradiol biosynthesis and action in the female's nervous system may contribute to the development of female-typical sexual behavior.     

Towards a functional neural systems model of developmental stuttering

This paper overviews recent developments in an ongoing program of brain imaging research on developmental stuttering that is being conducted at the University of Texas Health Science Center, San Antonio. This program has primarily used H₂¹⁵O PET imaging of different speaking tasks by right-handed adult male and female persistent stutterers, recovered stutterers and controls in order to isolate the neural regions that are functionally associated with stuttered speech. The principal findings have emerged from studies using condition contrasts and performance correlation techniques. The emerging findings from these studies are reviewed and referenced to a neural model of normal speech production recently proposed by Jürgens [Neurosci. Biobehav. Rev. 26 (2002) 235]. This paper will report (1) the reconfiguration of previous findings within the Jürgens Model; (2) preliminary findings of an investigation with late recovered stutterers; (3) an investigation of neural activations during a treatment procedure designed to produce a sustained improvement in fluency; and (4) an across-studies comparison that seeks to isolate neural regions within the Jürgens Model that are consistently associated with stuttering. Two regions appear to meet this criterion: right anterior insula (activated) and anterior middle and superior temporal gyri (deactivated) mainly in right hemisphere. The implications of these findings and the direction of future imaging investigations are discussed.

Educational objectives: The reader will learn about (1) recent uses of H₂¹⁵O PET imaging in stuttering research; (2) the use of a new neurological model of speech production in imaging research on stuttering; and (3) initial findings from PET imaging investigations of treated and recovered stutterers.     

STIMULUS FADING AS TREATMENT FOR OBSCENITY IN A BRAIN-INJURED ADULT

Obscene verbalizations of a person with traumatic brain injury were treated using stimulus fading as the singular form of intervention. Results of a functional assessment revealed that obscenity was maintained by negative reinforcement. Stimulus fading (initial elimination of instructional demands followed by their gradual reintroduction) produced immediate and substantial reductions in obscenity that were maintained as the frequency of demands increased to baseline levels. Potential applications of the use of antecedent treatment strategies are discussed.     

Synergistic effects of ethanol and cocaine on brain stimulation reward.

The effects of two widely abused drugs, ethanol and cocaine, were examined alone and in combination on intracranial reward processes. In agreement with previous research, higher doses of both cocaine and ethanol alone produced facilitation of behavior maintained by brain stimulation reward. Low intraperitoneal doses of ethanol and cocaine, which alone did not affect performance, were found to reduce stimulation reward threshold and modestly increase response rate. The enhancement of brain stimulation reward by the combination of ethanol and cocaine suggests that both drugs may produce their rewarding effects through common neuronal substrates and that they may potentiate the abuse of each other.     

A GROUP-ORIENTED CONTINGENCY TO INCREASE LEISURE ACTIVITIES OF ADULTS WITH TRAUMATIC BRAIN INJURY

An interdependent group-oriented contingency and graphic feedback were used to increase the activity levels of residents of a group home for persons with traumatic brain injury. Results showed that the intervention was effective for 4 of the 6 subjects. Individual performances must be examined when implementing group contingencies because all subjects may not respond.     

Involvement of reactive oxygen species in emotional stress: A hypothesis based on the immobilization stress-induced oxidative damage and antioxidant defense changes in rat brain,and the effect of antioxidant treatment with reduced glutathione

We examined the oxidative damage and antioxidant defense changes with immobilization-induced emotional stress in the rat brain. Though superoxide dismutase activity remained unchanged, brain peroxidation was significantly accelerated by the immobilization stress. Membrane fluidity study with spin labeling in brain cortical membrane showed that immobilization stress induced an increase in microviscosity of membrane layer near the surface and in the ordering of membrane proteins but a decrease in microviscosity at the core of the membrane bilayer. The Na, K-ATPase activity decreased whereas the levels of some monoamines and their metabolites increased along with their metabolic rate. The administration of reduced glutathione showed a protective effect on the immobilization stress-induced stomach bleeding, oxidative damage and abnormal changes in the brain antioxidant defenses. Based on these results and on previous reports, we hypothesize that immobilization stress may induce the formation of reactive oxygen species which weakens the brain antioxidant defenses and induces oxidative damage. The antioxidant administration of reduced glutathione provides further evidence to support the above hypothesis, and also may provide clues in the search for a rational therapy to emotional stress. A possible correlation of emotional stress to aging is also discussed.     

THE GOOD PRODUCTIVITY GAME: INCREASING WORK PERFORMANCE IN A REHABILITATION SETTING1

Simple reinforcement systems have been used to improve performance in a broad range of settings. For example, in classrooms, the “Good Behavior Game” has been shown to be very effective (Barrish, Saunders, and Wolf, Journal of Applied Behavior Analysis, 1969, 2 , 119–124). In industry, small bonuses were used to increase the punctuality of workers (Hermann, deMontes, Dominquez, Montes, and Hopkins, Journal of Applied Behavior Analysis, 1973, 6 , 503–572). In a sheltered workshop setting, Shroeder (Journal of Applied Behavior Analysis, 1972, 5 , 45–52) examined work rates under varying frequencies and amounts of reinforcement and response force. The present study involved the utilization of simple group contingencies to increase productivity in a rehabilitation industry. Four state hospital residents who were trainees at a rehabilitation industry participated in the study which examined the effects of feedback, and feedback plus the “Good Productivity Game” to improve work output. The task, for which the employees were paid a wage, involved sorting boards by size. When the employees were provided with feedback on the number of boards sorted during the observation period, productivity increased slightly over baseline. After a return to baseline, the “Good Productivity Game” was played. For performance, the game afforded the employees pseudo-competition (in that teams were paired against each other, but both teams always “won”) and simple rewards such as candy and early work termination. The game improved performance by 104% over the second baseline and by 64% over the third baseline. Data gathered on rates of on-task behavior by the employees correlate with the productivity rates. Data gathered on rates of staff attention paid to employees show little difference across conditions, thus corroborating the function of the “Good Productivity Game” in increasing work output. Although no formal data were collected, the staff continued to use the game with considerable success after the formal termination of the study. The “Good Productivity Game” appears useful in increasing work output in a rehabilitation setting. Further research should concentrate on the utility of the game throughout longer periods of the workday and over extended periods of time.     

Histological data: Hollard and Davison (1971)

As Mogenson and Cioé (1977) have assumed that our electrodes aimed at the ectostriatum (Hollard and Davison, 1971) were actually located there, we feel that a presentation of the histological data is necessary. Following termination of further experiments (Hollard, 1974) the pigeons, numbered 93, 95, and 119, were sacrificed and perfused with saline followed by 10% formalin. Sections, 50 microns thick, were cut on a freezing microtome. Prints were made by mounting each unstained section of a microscope slide and placing them in a standard photographic enlarger. The electrode tips of Pigeons 93 and 119 were located in the paleostriatal complex. The sections of Pigeon 95 were damaged and precise localization was not possible. Further work in this laboratory has also found that, using the same coordinates, electrode tips tend to fall in the paleostriatum, rather than in the more dorsal ectostriatum at which they are aimed. The paleostriatal placements tended to sustain self-stimulation, whereas others located in the ectostriatum sustained relatively low or unstable rates.