Subthalamic Nucleus Deep Brain Stimulation Alters Prefrontal Correlates of Emotion Induction.

OBJECTIVES: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) improves motor symptoms in advanced Parkinson's disease. STN DBS may also affect emotion, possibly by impacting a parallel limbic cortico-striatal circuit. The objective of this study was to investigate changes in prefrontal cortical activity related to DBS during an emotion induction task. MATERIALS AND METHODS: We used near infrared spectroscopy to monitor prefrontal cortex hemodynamic changes during an emotion induction task. Seven DBS patients were tested sequentially in the stimulation-on and stimulation-off states while on dopaminergic medication. Patients watched a series of positive, negative, and neutral videos. The general linear model was used to compare prefrontal oxygenated hemoglobin concentration between DBS states. RESULTS: Deep brain stimulation was correlated with prefrontal oxygenated hemoglobin changes relative to the stimulation off state in response to both positive and negative videos. These changes were specific to emotional stimuli and were not seen during neutral stimuli. CONCLUSIONS: These results suggest that STN stimulation influences the prefrontal cortical representation of positive and negative emotion induction.

Neuromodulation for restoring memory.

Disorders of learning and memory have a large social and economic impact in today's society. Unfortunately, existing medical treatments have shown limited clinical efficacy or potential for modification of the disease course. Deep brain stimulation is a successful treatment for movement disorders and has shown promise in a variety of other diseases including psychiatric disorders. The authors review the potential of neuromodulation for the treatment of disorders of learning and memory. They briefly discuss learning circuitry and its involvement in Alzheimer disease and traumatic brain injury. They then review the literature supporting various targets for neuromodulation to improve memory in animals and humans. Multiple targets including entorhinal cortex, fornix, nucleus basalis of Meynert, basal ganglia, and pedunculopontine nucleus have shown a promising potential for improving dysfunctional memory by mechanisms such as altering firing patterns in neuronal networks underlying memory and increasing synaptic plasticity and neurogenesis. Significant work remains to be done to translate these findings into durable clinical therapies.

Anterior Temporal Lobectomy for Refractory Status Epilepticus in Herpes Simplex Encephalitis.

BACKGROUND: Herpes simplex virus (HSV) is a common cause of viral encephalitis that can lead to refractory seizures. The primary treatment of HSV encephalitis is with acyclovir; however, surgery sometimes plays a role in obtaining tissue diagnosis or decompression in cases with severe mass effect. We report a unique case in which anterior temporal lobectomy was successfully used to treat refractory status epilepticus in HSV encephalitis. METHODS: Case report and review of the literature. RESULTS: We report a case of a 60-year-old man with HSV encephalitis, who presented with seizures originating from the right temporal lobe refractory to maximal medical management. Right anterior temporal lobectomy was performed for the purpose of treatment of refractory status epilepticus and obtaining tissue diagnosis, with ultimate resolution of seizures and excellent functional outcome. CONCLUSIONS: We suggest that anterior temporal lobectomy should be considered in cases of HSV encephalitis with refractory status epilepticus with clear unilateral origin.

Surgical Treatment of Trigeminal Neuralgia.

Trigeminal neuralgia is characterized by severe, episodic pain in the trigeminal nerve distribution. Medical therapy is the first line treatment. For patients with refractory pain, a variety of procedures including microvascular decompression, percutaneous radiofrequency rhizotomy, percutaneous glycerol rhizotomy, percutaneous balloon compression, and stereotactic radiosurgery are available. We review the literature and suggest that microvascular decompression remains the gold standard operative therapy. For patients with recurrent pain or who are poor operative candidates, percutaneous radiofrequency rhizotomy offers the best pain response rates and has the advantage of being able to selectively target affected trigeminal divisions.

Acute lymphocytic leukemia presenting as a single brain mass.

Hematologic malignancies most commonly spread to the central nervous system via leptomeningeal infiltration. We present a unique case of a woman who presented with a right parietal mass as the initial manifestation of B cell acute lymphocytic leukemia. Because the diagnosis was unclear at the time of presentation she underwent surgical debulking of the mass prior to treatment with chemotherapy. Unfortunately, she relapsed several months after treatment and ultimately entered hospice care. We review the literature surrounding management considerations in patients with intracranial leukemic involvement.