Independent Mobility Achieved through a Wireless Brain-Machine Interface.

Individuals with tetraplegia lack independent mobility, making them highly dependent on others to move from one place to another. Here, we describe how two macaques were able to use a wireless integrated system to control a robotic platform, over which they were sitting, to achieve independent mobility using the neuronal activity in their motor cortices. The activity of populations of single neurons was recorded using multiple electrode arrays implanted in the arm region of primary motor cortex, and decoded to achieve brain control of the platform. We found that free-running brain control of the platform (which was not equipped with any machine intelligence) was fast and accurate, resembling the performance achieved using joystick control. The decoding algorithms can be trained in the absence of joystick movements, as would be required for use by tetraplegic individuals, demonstrating that the non-human primate model is a good pre-clinical model for developing such a cortically-controlled movement prosthetic. Interestingly, we found that the response properties of some neurons differed greatly depending on the mode of control (joystick or brain control), suggesting different roles for these neurons in encoding movement intention and movement execution. These results demonstrate that independent mobility can be achieved without first training on prescribed motor movements, opening the door for the implementation of this technology in persons with tetraplegia.

Testicular microlithiasis predicts concurrent testicular germ cell tumors and intratubular germ cell neoplasia of unclassified type in adults: a meta-analysis and systematic review.

BACKGROUND: There is an increasing body of literature associating testicular microlithiasis (TM), a common finding on testicular ultrasound, with testicular germ cell tumor (TGCT) and intratubular germ cell neoplasia of unclassified type (ITGCNU). Determining these associations is pertinent both clinically and biologically. To the authors' knowledge, no previous systematic review or meta-analysis has been performed. METHODS: A comprehensive systematic literature review was performed without language restrictions through July 2009 and included an exhaustive search of electronic databases and article references. Two reviewers extracted data independently. Studies were categorized according to the clinical context in which sonography was performed. The primary study outcomes were concurrent diagnoses of TGCT or ITGCNU, with TM. In addition, studies with prospective follow-up of patients with TM were reviewed. RESULTS: Thirty-three studies met inclusion criteria. TM was not associated with an increased risk of TGCT in asymptomatic men. However, in referral populations, TM was associated overall with a risk ratio of 8.5 (95% confidence interval [CI], 4.5-16.1; P<.001) for a concurrent diagnosis of TGCT and 10.5 (95% CI, 5.3-20.8; P<.0001) for ITGCNU. Seventeen observational studies were identified in which the interval development of TGCT in patients with TM was reported; however, the majority of those studies did not report the follow-up of a control arm and could not be summarized. CONCLUSIONS: In the presence of risk factors, TM was associated with a substantially elevated risk of a concurrent diagnosis of TGCT and ITGCNU. The authors suggest modifications to recently proposed guidelines for the management of TM.