Anodal Stimulation Latency Response Differences Between Ipsilateral and Contralateral Motor Evoked Potentials in Hand Muscles.

Purpose: Purpose of this study was to analyze the latency and amplitude of transcranial motor evoked potentials responses from the contralateral and ipsilateral muscle groups to the same stimulus. If responses are because of activation of deeper structures, the latency of both the ipsilateral and the contralateral responses should have no difference. However, a difference in latency would suggest that activation might be occurring at different subcortical levels.

Photostability of 2,6-diaminopurine and its 2'-deoxyriboside investigated by femtosecond transient absorption spectroscopy.

Ultraviolet radiation (UVR) from the sun is essential for the prebiotic syntheses of nucleotides, but it can also induce photolesions such as the cyclobutane pyrimidine dimers (CPDs) to RNA or DNA oligonucleotide in prebiotic Earth. 2,6-Diaminopurine (26DAP) has been proposed to repair CPDs in high yield under prebiotic conditions and be a key component in enhancing the photostability of higher-order prebiotic DNA structures. However, its electronic relaxation pathways have not been studied, which is necessary to know whether 26DAP could have survived the intense UV fluxes of the prebiotic Earth.

Success Rate of Obtaining Baseline Somatosensory and Motor Evoked Potentials in 695 Consecutive Cranial and Spine Surgeries.

Purpose: Intraoperative neurophysiological monitoring has been well documented as an adjunctive technique that significantly decreases the risk of developing inadvertent sensory and motor deficits during cranial and spine surgeries. The ability to detect neurologic problems intraoperatively depends largely on accurately identifying changes that occur in somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs) during each procedure. Therefore, obtaining accurate and reproducible SSEP and MEP data during the initial setup is paramount for intraoperative monitoring.

Crossover Phenomena in Motor Evoked Potentials During Intraoperative Neurophysiological Monitoring of Cranial Surgeries.

Purpose: Transcranial motor evoked potentials (TcMEPs) are used to assess the corticospinal tract during surgery. Transcranial motor evoked potentials are elicited by preferentially activating the anode over the target cortex. Crossover occurs when stimulation also induces activation of ipsilateral motor evoked responses.

An Alternative Transcranial Motor Evoked Potential Montage to Minimize Ipsilateral "Crossover" Motor Responses.

Transcranial electrical motor evoked potential (TcMEP) is a modality utilized in intraoperative neurophysiological monitoring to assess the integrity of the corticospinal tract. Traditionally, TcMEPs are obtained by anodal stimulation of the scalp over the motor cortex of the selected hemisphere and referenced to the contralateral hemisphere. Subsequent compound motor action potential responses (CMAPs) are recorded at various muscles.

Factors Associated With Inadequate Intraoperative Baseline Lower Extremity Somatosensory Evoked Potentials.

Purpose: Intraoperative neurophysiologic monitoring involves the use of various modalities, including somatosensory evoked potentials (SEP), to assess the integrity of the at-risk nervous system during surgeries. Reliable baseline tracings are important because they are data against which future tracings are compared to detect potential injury. In some cases, adequate baselines may be difficult to achieve.

Comparison of Transcranial Motor Evoked Potential Amplitude Responses Between Intramuscular and Subcutaneous Needles in Proximal Thigh Muscle.

Purpose: Successful intraoperative neurophysiological monitoring is predicated on the presence of adequate baseline-evoked potentials. We have observed that transcranial motor evoked potentials (TcMEPs) yield more robust responses in the distal muscles compared with proximal muscles. One possible explanation is the distance from the needle to the muscle generator.

Differences in the Transcranial Motor Evoked Potentials Between Proximal and Distal Lower Extremity Muscles.

Purpose: Transcranial motor evoked potentials (TcMEPs) are the preferred modality to monitor the integrity of motor pathways during surgery. Recently, it has also been used as a method to help with detection of nerve roots injuries. Adequate baseline muscle responses are vital to detect nerve injury.

Posterior circulation cerebral hyperperfusion syndrome after high flow external carotid artery to middle cerebral artery bypass.

We present the first report, to our knowledge, in which revascularization of the middle cerebral artery (MCA) with a high flow extracranial-intracranial procedure resulted in symptomatic hyperemia of the posterior circulation. Cerebral hyperperfusion syndrome (CHS) is a poorly understood phenomenon that is classically seen in the distribution of a revascularized artery. A 37-year-old woman presented with a 3 month history of cognitive and speech difficulties, persistent headaches, weakness, numbness, and paresthesia which was worse in the right extremities and face.

Overview of Intraoperative Neurophysiological Monitoring During Spine Surgery.

Intraoperative neurophysiologic monitoring has had major advances in the past few decades. During spine surgery, the use of multimodality monitoring enables us to assess the integrity of the spinal cord, nerve roots, and peripheral nerves. The authors present a practical approach to the current modalities in use during spine surgery, including somatosensory evoked potentials, motor evoked potentials, spinal D-waves, and free-run and triggered electromyography.

Assessing fidelity of core components in a mindfulness and yoga intervention for urban youth: applying the CORE Process.

In the past years, the number of mindfulness-based intervention and prevention programs has increased steadily. In order to achieve the intended program outcomes, program implementers need to understand the essential and indispensable components that define a program's success. This chapter describes the complex process of identifying the core components of a mindfulness and yoga program for urban early adolescents through the systematic study of fidelity of implementation of the intervention.

Operative strategies for minimizing hearing loss and other major complications associated with microvascular decompression for trigeminal neuralgia.

Objective: To retrospectively assess the surgical outcomes and complication rates following microvascular decompression (MVD) for trigeminal neuralgia, using a targeted, restricted retrosigmoid approach.

Methods: During the period 1994-2009, a total of 119 patients underwent MVD for trigeminal neuralgia. A retrospective review was conducted in order to assess pain outcomes following surgery and at most recent follow-up.

Intraoperative neurophysiological monitoring during spine surgery: a review.

Spinal surgery involves a wide spectrum of procedures during which the spinal cord, nerve roots, and key blood vessels are frequently placed at risk for injury. Neuromonitoring provides an opportunity to assess the functional integrity of susceptible neural elements during surgery. The methodology of obtaining and interpreting data from various neuromonitoring modalities-such as somatosensory evoked potentials, motor evoked potentials, spontaneous electromyography, and triggered electromyography-is reviewed in this report.

The use of transcranial magnetic stimulation for monitoring descending spinal cord motor function.

This report describes our initial clinical experience using transcranial magnetic stimulation for monitoring spinal cord motor function during surgical procedures. Motor evoked potentials were elicited using a cap shaped coil placed on the scalp of 27 patients while recording peripheral motor responses (compound muscle action potentials--CMAPs) from the upper (N = 1) or lower limbs (N = 26). Wherever possible, cortical somatosensory responses (SEPs) were also monitored by electrically stimulating the left and right posterior tibial nerve (N = 25) or the median nerve (N = 1).