Noninvasively recorded high-gamma signals improve synchrony of force feedback in a novel neurorehabilitation brain-machine interface for brain injury.

Objective.Brain injury is the leading cause of long-term disability worldwide, often resulting in impaired hand function. Brain-machine interfaces (BMIs) offer a potential way to improve hand function. BMIs often target replacing lost function, but may also be employed in neurorehabilitation (nrBMI) by facilitating neural plasticity and functional recovery. Here, we report a novel nrBMI capable of acquiring high-γ(70-115 Hz) information through a unique post-traumatic brain injury (TBI) hemicraniectomy window model, and delivering sensory feedback that is synchronized with, and proportional to, intended grasp force.Approach. We developed the nrBMI to use electroencephalogram recorded over a hemicraniectomy (hEEG) in individuals with TBI. The nrBMI empowered users to exert continuous, proportional control of applied force, and provided continuous force feedback. We report the results of an initial testing group of three human participants with TBI, along with a control group of three skull- and motor-intact volunteers.Main results. All participants controlled the nrBMI successfully, with high initial success rates (2 of 6 participants) or performance that improved over time (4 of 6 participants). We observed high-γmodulation with force intent in hEEG but not skull-intact EEG. Most significantly, we found that high-γcontrol significantly improved the timing synchronization between neural modulation onset and nrBMI output/haptic feedback (compared to low-frequency nrBMI control).Significance. These proof-of-concept results show that high-γnrBMIs can be used by individuals with impaired ability to control force (without immediately resorting to invasive signals like electrocorticography). Of note, the nrBMI includes a parameter to change the fraction of control shared between decoded intent and volitional force, to adjust for recovery progress. The improved synchrony between neural modulations and force control for high-γsignals is potentially important for maximizing the ability of nrBMIs to induce plasticity in neural circuits. Inducing plasticity is critical to functional recovery after brain injury.

Hemicraniectomy in Traumatic Brain Injury: A Noninvasive Platform to Investigate High Gamma Activity for Brain Machine Interfaces.

Brain-machine interfaces (BMIs) translate brain signals into control signals for an external device, such as a computer cursor or robotic limb. These signals can be obtained either noninvasively or invasively. Invasive recordings, using electrocorticography (ECoG) or intracortical microelectrodes, provide higher bandwidth and more informative signals. Rehabilitative BMIs, which aim to drive plasticity in the brain to enhance recovery after brain injury, have almost exclusively used non-invasive recordings, such electroencephalography (EEG) or magnetoencephalography (MEG), which have limited bandwidth and information content. Invasive recordings provide more information and spatiotemporal resolution, but do incur risk, and thus are not usually investigated in people with stroke or traumatic brain injury (TBI). Here, in this paper, we describe a new BMI paradigm to investigate the use of higher frequency signals in brain-injured subjects without incurring significant risk. We recorded EEG in TBI subjects who required hemicraniectomies (removal of a part of the skull). EEG over the hemicraniectomy (hEEG) contained substantial information in the high gamma frequency range (65-115 Hz). Using this information, we decoded continuous finger flexion force with moderate to high accuracy (variance accounted for 0.06 to 0.52), which at best approaches that using epidural signals. These results indicate that people with hemicraniectomies can provide a useful resource for developing BMI therapies for the treatment of brain injury.

Psychosis Following an Increase in Intrathecal Baclofen.

Baclofen is a commonly used medication to treat spasticity in neurologic disorders. In the traumatic brain injury (TBI) population, the intrathecal administration of baclofen is often preferred over oral administration due to cognitive side effects. Here we report on a case of a psychotic episode following an increase in intrathecal baclofen in a young man with a history of a TBI. Although intrathecal baclofen is commonly used and is generally well tolerated, this case highlights an important potential effect of intrathecal baclofen that has rarely been reported in the literature. LEVEL OF EVIDENCE: V.

Subacute and subchronic toxicity of Avalon(®) mixture (bentazone+dicamba) to rats.

Subacute and subchronic toxicity of the herbicide Avalon(®), a mixture of bentazone and dicamba, were tested on rats. Avalon(®) was administered at dose levels of 250, 500 and 1000mg/kg body weight/day for 28 and 90 days. Alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) activities were monitored together with biochemistry parameters. The results showed that the mixture caused increases in the activities of ALT, AST and ALP, elevated concentrations of sodium, albumin and albumin/globulin ratio in males. In females, ALT activity, cholesterol and phosphate levels were increased. The changes generally were dose related and, in most cases, females exhibited lower susceptibility than males. The effects of a mixture are, in the most cases, different from the effects of the individual substances. The effects of bentazone were not prevalent which would be expected taking the composition of the mixture into account.

A case-control study of myelodysplastic syndromes in Belgrade (Serbia Montenegro).

The objective of the study was to investigate factors related to the occurrence of myelodysplatic syndromes (MDS) in the population of Belgrade (Serbia Montenegro). The case-control study was conducted during the period 2000-2003. The study group consisted of 80 newly diagnosed MDS patients and 160 sex- and age-matched hospital controls with nonmalignant and noninfectious diseases. The disease categories in the control group were circulatory (51 patients, 32%), gastrointestinal (53 patients, 33%), and ophthalmological (56 patients, 35%) disorders. Conditional univariate and multivariate logistic regression analyses were applied. Multivariate analysis showed the following factors to be significantly related to MDS: exposure to chemicals (OR = 10.8, 95%CI 3.2-36.2, p = 0.0001), viral upper respiratory tract infections (twice a year or more, OR = 5.8, 95%CI 2.5-13.6, p = 0.0001), exposure to insecticides, pesticides and herbicides (OR = 5.2, 95%CI 1.8-15.1, p = 0.003), coffee (OR = 5.1, 95%CI 1.9-13.7, p = 0.001), and alcohol consumption (OR = 2.2, 95%CI 1.1-4.6, p = 0.033). The findings support the hypotheses that exposure to chemical agents, pesticides, insecticides, and herbicides, certain lifestyle factors (alcohol and coffee consumption), and frequent viral infections may be involved in the etiology of MDS, but these results should be confirmed by further investigations.

The relative contribution of war experiences and exile-related stressors to levels of psychological distress among Bosnian refugees.

This study examined the relative contribution of 2 exile-related variables--social isolation and daily activity level--and war experiences of violence and loss, to levels of PTSD and depressive symptomatology in 2 groups of Bosnian refugees, 1 clinical group (N = 59) and the other a nonclinical community (N = 40) group. As hypothesized, exposure to war-related violence was highly predictive of PTSD symptoms in both groups; in addition, social isolation was significantly related to PTSD symptomatology in the community group. In contrast, depressive symptomatology was accounted for primarily by the exile-related stressors. For the clinical group, depressive symptoms were also accounted for by experiences of war-related loss. The implications of these findings for mental health interventions with refugees are considered.