Fully implanted adaptive deep brain stimulation in freely moving essential tremor patients.

OBJECTIVE: Deep brain stimulation (DBS) is a safe and established treatment for essential tremor (ET) and several other movement disorders. One approach to improving DBS therapy is adaptive DBS (aDBS), in which stimulation parameters are modulated in real time based on biofeedback from either external or implanted sensors. Previously tested systems have fallen short of translational applicability due to the requirement for patients to continuously wear the necessary sensors or processing devices, as well as privacy and security concerns. APPROACH: We designed and implemented a translation-ready training data collection system for fully implanted aDBS. Two patients chronically implanted with electrocorticography strips over the hand portion of M1 and DBS probes in the ipsilateral ventral intermediate nucleus of the thalamus for treatment of ET were recruited for this study. Training was conducted using a translation-ready distributed training procedure, allowing a substantially higher degree of control over data collection than previous works. A linear classifier was trained using this system, biased towards activating stimulation in accordance with clinical considerations. MAIN RESULTS: The clinically relevant average false negative rate, defined as fraction of time during which stimulation dropped below [Formula: see text] clinical levels during movement epochs, was 0.036. Tremor suppression, calculated through analysis of gyroscope data, was 33.2% more effective on average with aDBS than with continuous DBS. During a period of free movement with aDBS, one patient reported a slight paresthesia; patients noticed no difference in treatment efficacy between systems. SIGNIFICANCE: Here is presented the first translation-ready training procedure for a fully embedded aDBS control system for MDs and one of the first examples of such a system in ET, adding to the consensus that fully implanted aDBS systems are sufficiently mature for broader deployment in treatment of movement disorders.

Ongoing research to identify environmental risk factors in breast carcinoma.

Environmental exposures, timing and duration of exposure, and one's genetic susceptibility all contribute to breast carcinoma and its progression. The purpose of this article was to identify known and suspected environmental causes of breast carcinoma, identify some environmental risk factors that may represent significant risk factors for certain groups, and describe current studies, supported by the National Institutes of Health/National Institute of Environmental Health Sciences, that clarify how environmental factors contribute to the development of breast carcinoma. Known and suspected environmental risk factors include organochlorine pesticides and other synthetic chemicals, hormonal factors (including exogenous endocrine disrupters), diet, tobacco and alcohol use, radiation, and magnetic fields. In at least 50% of breast carcinoma cases, none of the known risk factors apply. It is likely that an environmental component accounts for much of the unknown 50% of risk. Knowing the environmental factors for breast carcinoma development is an area that should be investigated intensely because it offers our best hope for prevention. Understanding why African-American women have a more aggressive form of breast carcinoma, whether they receive adequate follow-up treatment, and how these factors contribute to increased mortality rates requires further exploration. Data that demonstrate the lower incidence rate of breast carcinoma in Asian women, the relation to low fat diets and diets high in phytoestrogens, and how this might serve as a model for all women should be investigated. Finally, differences in behavioral and cultural attitudes, ethnicity, economic status, and life-style influences among different groups of women require further study to determine how these factors contribute to enhancing or reducing breast carcinoma risk.

Growth hormone-releasing hormone depletion in the female rat: similarities to aging.

The age-related decline in growth hormone (GH) secretion has been largely attributed to age-related degeneration of hypothalamic growth hormone-releasing hormone (GHRH)-producing neurons. GH decline has recently been linked to age-related bone changes in humans. Bone loss and decreased bone strength are common in aging rats and humans, but density of remaining mineral tissue is known to be increased. The effect of induced hypothalamic GHRH deficiency on bone was assessed, and similarities between bone changes encountered and those taking place in aging were identified. Female rats received monosodium glutamate (MSG) following birth, and they were euthanized at 19 weeks of age. Femurs from MSG-treated rats had greater mineral density (p < .05), greater mineral/matrix ratio (p < .01), lower mineral apposition rate (p < .005), and lower bone formation rate (p < .05). These results suggest that hypothalamic GHRH decline plays a substantial role in the development of bone pathology similar to that observed in aging individuals.

Ketamine and military anaesthesia. The effect of heavy papaveretum premedication and Althesin induction on the incidence of emergence phenomena.

An anaesthetic technique suitable for military field anaesthesia was sought which would attenuate the psychic side effects of ketamine. Heavy premedication with 30 mg of papaveretum and induction of anaesthesia with Althesin were evaluated. A combination of the two lowered the incidence of side effects, but they still occurred frequently enough to pose problems. Ketamine sequelae are considered incompatible with the battlefield environment.