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Postactivation depression of the Hoffmann reflex is reduced in Parkinson's disease (PD), but how the recovery is influenced by the state of the muscle is unknown. The present pilot study examined postactivation depression in PD at rest and during a voluntary contraction while patients were off treatment and while receiving medications and/or deep brain stimulation.The authors recruited nine patients with PD treated with implanted deep brain stimulation and examined postactivation depression under four treatment conditions. Paired pulses were delivered 25 to 300 ms apart, and soleus Hoffmann reflex recovery was tested at rest and during voluntary plantar flexion. Trials were matched for background muscle activity and compared with 10 age-matched controls.Patients with Parkinson disease who were OFF medications (OFF meds) and OFF stimulation (OFF stim) at rest showed less postactivation depression at the 300 ms interpulse interval (86.1% ± 21.0%) relative to control subjects (36.4% ± 6.1%; P0.05). Postactivation depression was restored when dopaminergic medication and/or deep brain stimulation was applied. Comparisons between resting and active motor states revealed that the recovery curves were similar OFF meds/OFF stim owing to faster recovery in PD seen at rest. In contrast, the effect of the motor state was different ON meds/OFF stim and ON meds/ON stim (both P0.05), with a nonsignificant trend OFF meds/ON stim ( P0.08). During a contraction, recovery curves were similar between all treatment conditions in PD and control.Disrupted Hoffmann reflex recovery is restored to control levels in PD patients at rest when receiving medications and/or deep brain stimulation or when engaged in voluntary contraction.

Deep brain stimulation (DBS) is now widely used in the treatment of Parkinson's disease, tremor, and dystonia. This review examines recent developments in the application of DBS to the management of movement disorders.In Parkinson's disease, recent work has demonstrated that early DBS may have a significant benefit on quality of life and motor symptoms while permitting a decrease in levodopa equivalent dosage. Thalamic DBS continues to be a well established target for the treatment of tremor, although recent work suggests that alternative targets such as the posterior subthalamic area may be similarly efficacious. The treatment of primary dystonia with DBS has been established in multiple recent trials, demonstrating prolonged symptomatic benefit.DBS is now an established symptomatic treatment modality for Parkinson's disease and other movement disorders. Future work will undoubtedly involve establishing new indications and targets in the treatment of movement disorders with further refinements to existing technology. Ultimately, these methods combined with biologically based therapies may catalyze a shift from symptomatic treatment to actually modifying the natural history of neurodegenerative diseases such as Parkinson's disease.

INTRODUCTION: Recent developments in optical science and image processing have miniaturized the components required for confocal microscopy. Clinical confocal imaging applications have emerged, including assessment of colonic mucosal dysplasia during colonoscopy. We present our initial experience with handheld, miniaturized confocal imaging in a murine brain tumor model. METHODS: Twelve C57/BL6 mice were implanted intracranially with 10 5 GL261 glioblastoma cells. The brains of 6 anesthetized mice each at 14 and 21 days after implantation were exposed surgically, and the brain surface was imaged using a handheld confocal probe affixed to a stereotactic frame. The probe was moved systematically over regions of normal and tumor-containing tissue. Intravenous fluorescein and topical acriflavine contrast agents were used. Biopsies were obtained at each imaging site beneath the probe and assessed histologically. Mice were killed after imaging. RESULTS: Handheld confocal imaging produced exquisite images, well-correlated with corresponding histologic sections, of cellular shape and tissue architecture in murine brain infiltrated by glial neoplasm. Reproducible patterns of cortical vasculature, as well as normal gray and white matter, were identified. Imaging effectively distinguished between tumor and nontumor tissue, including infiltrative tumor margins. Margins were easily identified by observers without prior neuropathology training after minimum experience with the technology. CONCLUSION: Miniaturized handheld confocal imaging may assist neurosurgeons in detecting infiltrative brain tumor margins during surgery. It may help to avoid sampling error during biopsy of heterogeneous glial neoplasms, with the potential to supplement conventional intraoperative frozen section pathology. Clinical trials are warranted on the basis of these promising initial results.

Objective In many locations, neurosurgeons still use stereotactic- or anatomic-based craniocerebral topography systems to identify cortical landmarks. However, their predictive value for identifying two key landmarks--the central sulcus (CS) and lateral sulcus (LS)--has never been evaluated. We quantitatively compare leading craniocerebral topographic methods and review their historical significance for neurosurgery. Methods On 12 cadaveric head sides, the methods of Broca, Reid, Poirier, Taylor-Haughton, and Rhoton were used to predict positions of the CS and LS. After craniotomy, the actual CS, LS, and the superior and inferior Rolandic points were identified. Distances between predicted positions and actual structures were measured, and the systems were compared. Results The actual superior Rolandic point was 4.6 +/- 2.9 mm anterior to prediction by Broca's method; 4.3 +/- 2.13 mm anterior to the Poirier, Taylor-Haughton, and Rhoton methods; and 3.26 +/- 3.17 mm anterior or posterior using Reid's method. The actual inferior Rolandic point was anteroinferior to all predictions: 5.87 +/- 3.1 mm by Rhoton, 6.97 +/- 3.55 mm by Broca, 7.64 +/- 2.54 mm by Poirier, and 7.61 +/- 3.85 mm by Reid and Taylor-Haughton. The actual LS was 2.33 mm away from the predicted point using Poirier's method, and 2.00 mm away from the predicted point using the Reid, Taylor-Haughton, and Rhoton methods. Conclusion Predicting positions of the CS and LS to within a few millimeters, these landmark methods remain reliable for cerebral localization. Largely initiated by the work of Paul Broca, these systems lay at the development of a practical method of neurosurgery in the late 19th century.