Stepped Geomorphology Shaped the Phylogeographic Structure of a Widespread Tree Species (Toxicodendron vernicifluum, Anacardiaceae) in East Asia.

Species' phylogeographic patterns reflect the interplay between landscape features, climatic forces, and evolutionary processes. Here, we used two chloroplast DNA (cpDNA) markers (trnL and trnL-F) to explore the role of stepped geomorphology in shaping the phylogeographic structure of Toxicodendron vernicifluum, an economically important tree species widely distributed in East Asia. The range-wide pattern of sequence variation was analyzed based on a dataset including 357 individuals from China, together with published sequences of 92 individuals mainly from Japan and South Korea. We identified five chloroplast haplotypes based on seven substitutions across the 717-bp alignment. A clear east-west phylogeographic break was recovered according to the stepped landforms of mainland China. The wild trees of the western clade were found to be geographically restricted to the "middle step", which is characterized by high mountains and plateaus, while those of the eastern clade were confined to the "low step", which is mainly made up of hills and plains. The two major clades were estimated to have diverged during the Early Pleistocene, suggesting that the cool glacial climate may have caused the ancestral population to retreat to at least two glacial refugia, leading to allopatric divergence in response to long-term geographic isolation. Migration vector analyses based on the outputs of ecological niche models (ENMs) supported a gradual range expansion since the Last Interglacial. Mountain ranges in western China and the East China Sea land bridge were inferred to be dispersal corridors in the western and eastern distributions of T. vernicifluum, respectively. Overall, our study provides solid evidence for the role of stepped geomorphology in shaping the phylogeographic patterns of T. vernicifluum. The resulting east-west genetic discontinuities could persist for a long time, and could occur at a much larger scale than previously reported, extending from subtropical (e.g., the Xuefeng Mountain) to warm-temperate China (e.g., the Taihang Mountain).

Suppression of Superficial Microglial Activation by Spinal Cord Stimulation Attenuates Neuropathic Pain Following Sciatic Nerve Injury in Rats.

We evaluated the mechanisms underlying the spinal cord stimulation (SCS)-induced analgesic effect on neuropathic pain following spared nerve injury (SNI). On day 3 after SNI, SCS was performed for 6 h by using electrodes paraspinally placed on the L4-S1 spinal cord. The effects of SCS and intraperitoneal minocycline administration on plantar mechanical sensitivity, microglial activation, and neuronal excitability in the L4 dorsal horn were assessed on day 3 after SNI. The somatosensory cortical responses to electrical stimulation of the hind paw on day 3 following SNI were examined by using in vivo optical imaging with a voltage-sensitive dye. On day 3 after SNI, plantar mechanical hypersensitivity and enhanced microglial activation were suppressed by minocycline or SCS, and L4 dorsal horn nociceptive neuronal hyperexcitability was suppressed by SCS. In vivo optical imaging also revealed that electrical stimulation of the hind paw-activated areas in the somatosensory cortex was decreased by SCS. The present findings suggest that SCS could suppress plantar SNI-induced neuropathic pain via inhibition of microglial activation in the L4 dorsal horn, which is involved in spinal neuronal hyperexcitability. SCS is likely to be a potential alternative and complementary medicine therapy to alleviate neuropathic pain following nerve injury.

[Frontal Lobe Signs Caused by Migration of a Burr Hole Cap into the Brain after Deep Brain Stimulation Surgery:A Case Report].

We report a rare complication in a patient with Parkinson's disease who underwent deep brain stimulation(DBS)surgery. The patient was a 60-year-old woman who presented with frontal lobe signs, including ataxic gait and memory disturbance, that were caused by the unexpected migration of a burr hole cap into the brain three to four months after surgery. The patient had no incidence of a head injury prior to development of symptoms. The patient underwent surgery to extract the migrated cap from the frontal lobe, and her symptoms improved several months after the operation. The cap serves to fix the DBS lead to the skull using an adjunctive burr hole ring. It was intraoperatively confirmed that only the cap detached from the ring, and no cap or ring defects were detected in a postoperative quality check by the manufacturer. We have previously utilized a burr hole ring and cap, which are packaged along with the DBS electrode, when employing the product made by Medtronic Inc. No previous report has described the cap packed in the official DBS kit to have migrated into the intracranial space. It seems unlikely that the cap migration into the intracranial space would occur without the cap and/or ring breaking through either traumatic injury or from manufacturing defects. It is important to consider the migration of a burr hole cap into the intracranial space in the absence of head injury as a possible device complication after DBS surgery.

Bipolar dual-lead spinal cord stimulation between two electrodes on the ventral and dorsal sides of the spinal cord: consideration of putative mechanisms.

We have applied bipolar dual-lead spinal cord stimulation (SCS) between two cylinder-type electrodes placed on the ventral and dorsal sides of the spinal cord (dual-VD-SCS). A 36-year-old man suffered from burning pain from his right elbow down to his hand after brachial plexus avulsion. The areas with paresthesia induced by conventional SCS did not include the painful hand area. However, dual-VD-SCS completely induced paresthesia in the painful hand area. We speculate that dual-VD-SCS can be applied to stimulate deeper sites of the dorsal column and dorsal horn than conventional SCS and is useful for pain reduction.

Brain magnetic resonance imaging examination in a patient with non-magnetic resonance conditional pacemaker.

Clinical dilemmas arise when patients with a non-magnetic resonance (MR) conditional pacemaker are required to undergo magnetic resonance imaging (MRI). We encountered a pacemaker patient with debilitating non-motor symptoms of Parkinson׳s disease, who required an MRI prior to deep brain stimulation (DBS) surgery. MRI was performed safely without adverse events despite the presence of a conventional pacemaker.

Predictive Factors for Long-term Outcome of Subthalamic Nucleus Deep Brain Stimulation for Parkinson's Disease.

Despite the recognition of the usefulness of subthalamic nucleus deep brain stimulation (STN-DBS) for the treatment of Parkinson's disease (PD), preoperative predictive factors for the long-term outcome of STN-DBS are not sufficiently established. We performed this study to determine such predictive factors. The subjects were 66 patients who were classified into two groups on the basis of their activities of daily living (ADL) evaluated five years after the STN-DBS surgery: 33 patients were assigned to the independent ADL group (group I) and the remaining 33 patients to the dependent ADL group (group D). Group I patients showed a Schwab and England (S&E) scale score of more than 70 during the off-period, indicating that these patients can maintain their independent ADL all the time. Group D patients showed a score of 70 or lower during the off-period, indicating that these patients cannot maintain their independent ADL for an entire day. We studied the differences in the preoperative state between these two groups. Statistically significant differences were noted in PD onset age, age at surgery, preoperative unified Parkinson's disease rating scale (UPDRS) part I score, part II score, total subscore for axial symptoms in part III, mini-mental state examination (MMSE) score and S&E score. Multiple logistic regression analysis showed that the significant independent variables related to long-term independent ADL were the age at surgery, MMSE score and preoperative S&E scale score during the off-period. The PD onset age, age at surgery, preoperative high-level ADL, cognitive function, and axial symptoms are important predictive factors for the long-term outcome of STN-DBS.

Spinal Cord Stimulation for Vegetative State and Minimally Conscious State: Changes in Consciousness Level and Motor Function.

Twenty-one vegetative state (VS) patients and 10 minimally conscious state (MCS) patients were treated by spinal cord stimulation (SCS) following an electrophysiological evaluation 3 months or more after the onset of brain injury.A flexible four-contact cylindrical electrode was inserted into the epidural space of the cervical vertebrae, and placed at cervical levels C2-C4. Five-hertz stimulation was applied for 5 min every 30 min during the daytime at an intensity that produced muscle twitches of the upper extremities.Both the fifth wave in the auditory brainstem response (ABR) and N20 in the somatosensory evoked potential (SEP) were detected in 8 of the 21 VS patients and 9 of the 10 MCS patients. Of the 3 VS patients and 7 MCS patients who recovered following SCS therapy, all showed a preserved fifth wave in the ABR and N20 in the SEP, and all had received SCS therapy within 9 months after the onset of brain injury. Although the 3 patients who recovered from VS remained in a bedridden state, all 7 patients who recovered from MCS were able to emerge from the bedridden state within 12 months after the start of SCS.Five-hertz cervical SCS caused increased cerebral blood flow (CBF) and induced muscle twitches of the upper extremities, and MCS patients showed a remarkable recovery of consciousness and motor function in the upper extremities compared with the lower extremities. This SCS method could be a new neuromodulation and neurorehabilitation technique, and MCS patients may be good candidates for SCS therapy.

Glioblastoma Multiforme Developed during Chronic Deep Brain Stimulation for Parkinson Disease.

BACKGROUND: In this reported case, 7 years after the start of deep brain stimulation (DBS) of the bilateral subthalamic nucleus (STN), glioblastoma multiforme (GBM) developed around the implanted DBS lead. CASE REPORT: The brain tumor formed from the subcortical white matter to the corpus callosum bilaterally around the DBS lead but did not extend in the direction of the contact points of the lead. The GBM showed a typical invasion pattern of the butterfly type. We report the first case of GBM that developed 7 years after the start of STN-DBS. CONCLUSION: Considering the low rate of GBM occurrence in association with DBS, the location of the glioma, and the pattern of tumor invasion, we speculate that GBM developed spontaneously and extended to some degree around the DBS lead. Moreover, there is a very slight possibility that continuous electrical brain stimulation itself induced the development of the brain glioma.

Importance of Pharmacological Evaluation in the Treatment of Poststroke Pain by Spinal Cord Stimulation.

OBJECTIVES: Spinal cord stimulation (SCS) is not typically recommended for the treatment of central poststroke pain (CPSP). We examined whether the pharmacological evaluation of CPSP is useful for selecting the candidates for SCS. MATERIALS AND METHODS: Changes in visual analog scale (VAS) scores for pain following pharmacological evaluation using morphine, thiopental, and ketamine were compared with those following SCS in 22 CPSP patients. RESULTS: Twelve of the 22 (54.5%) patients in the ketamine test and thiopental test, and 5 (22.7%) of the 22 patients in the morphine test showed a more than 40% reduction in VAS score and were judged as "sensitive." Pain relief by SCS was estimated as excellent (≧60% VAS score reduction) in three patients, good (30-59% reduction) in nine patients, and fair (10-29% reduction) in seven patients 24 months after the start of SCS. The remaining 3 patients evaluated as having poor pain relief (<10% reduction) only underwent test SCS. VAS score reduction induced by SCS was more significant in ketamine-sensitive patients than in ketamine-resistant patients during the test SCS (p < 0.01, Mann-Whitney's U test) and 24 months after the start of chronic SCS (p < 0.05). However, there were no significant differences in results for thiopental-sensitive/thiopental-resistant or morphine-sensitive/morphine-resistant patients during the test SCS and 24 months after chronic SCS. Analysis of the rate of VAS score reduction by pharmacological evaluation and SCS showed significant correlations with the results of the ketamine test (r = 0.670, p = 0.001, Pearson's correlation coefficient test), but not with those of the thiopental (r = 0.291, p = 0.231) or morphine test (r = 0.327, p = 0.175). CONCLUSION: We speculate that the pharmacological evaluation of CPSP patients can be a useful tool for selecting candidates for SCS.

Multitarget, dual-electrode deep brain stimulation of the thalamus and subthalamic area for treatment of Holmes' tremor.

OBJECT: Holmes' tremor (HT) is generally considered to be a symptomatic tremor associated with lesions of the cerebellum, midbrain, or thalamus. Deep brain stimulation (DBS) therapy for essential tremor and parkinsonian tremor has proved quite successful. In contrast, surgical treatment outcomes for HT have often been disappointing. The use of 2 ipsilateral DBS electrodes implanted in parallel within the thalamus for severe essential tremor has been reported. Since dual-lead stimulation within a single target can cover a wider area than single-lead stimulation, it produces greater effects. On the other hand, DBS of the subthalamic area (SA) was recently reported to be effective for refractory tremor. METHODS: The authors implanted 2 DBS electrodes (one at the nucleus ventralis oralis/nucleus ventralis intermedius and the other at the SA) in 4 patients with HT. For more than 2 years after implantation, each patient's tremor was evaluated using a tremor rating scale under the following 4 conditions of stimulation: "on" for both thalamus and SA DBS; "off" for both thalamus and SA DBS; "on" for thalamus and "off" for SA DBS; and "on" for SA and "off" for thalamus DBS. RESULTS: The tremor in all patients was improved for more than 2 years (mean 25.8 ± 3.5 months). Stimulation with 2 electrodes exerted greater effect on the tremor than did 1-electrode stimulation. Interestingly, in all patients progressive effects were observed, and in one patient treated with DBS for 1 year, tremor did not appear even while stimulation was temporarily switched off, suggesting irreversible improvement effects. The presence of both resting and intentional/action tremor implies combined destruction of the pallidothalamic and cerebellothalamic pathways in HT. A larger stimulation area may thus be required for HT patients. Multitarget, dual-lead stimulation permits coverage of the wide area needed to suppress the tremor without adverse effects of stimulation. Some reorganization of the neural network may be involved in the development of HT because the tremor appears several months after the primary insult. The mechanism underlying the absence of tremor while stimulation was temporarily off remains unclear, but the DBS may have normalized the abnormal neural network. CONCLUSIONS: The authors successfully treated patients with severe HT by using dual-electrode DBS over a long period. Such DBS may offer an effective and safe treatment modality for intractable HT.

Simulation to locate burr hole sites in a patient for deep brain stimulation surgery and clipping of intracranial aneurysm.

BACKGROUND AND OBJECTIVE: Deep brain stimulation (DBS) candidates with neurologic diseases such as unruptured aneurysm present additional challenges to neurosurgeons when craniotomy must precede DBS surgery. Such craniotomy may potentially overlap with intended burr hole sites for the later insertion of DBS electrodes, and the skin incision for craniotomy may lie very close to or intersect with that for the burr holes. We report here a case of forehead craniotomy prior to DBS surgery in which we employed a neuronavigation system to simulate locations for the craniotomy and burr holes. METHOD: A 62-year-old male patient with Parkinson's disease was a candidate for DBS. He also had an aneurysm and was planned first to undergo frontal craniotomy for clipping before the DBS surgery. The locations of the craniotomy, burr holes, and skin incisions were therefore simulated using a neuronavigation system during craniotomy. RESULTS: Two weeks after the craniotomy, the patient underwent DBS surgery. Planning software confirmed the absence of cortical veins beneath the entry points of tentative burr holes and aided trajectory planning. The DBS surgery was performed without the interference of the burr holes and head pins and the craniotomy. CONCLUSION: Simulation of the locations of craniotomy and burr holes using a neuronavigation system proved valuable in the present case of frontal craniotomy before DBS surgery.

Deep brain stimulation and spinal cord stimulation for vegetative state and minimally conscious state.

OBJECTIVE: On the basis of the findings of the electrophysiological evaluation of vegetative state (VS) and minimally conscious state (MCS), the effect of deep brain stimulation (DBS) was examined according to long-term follow-up results. The results of spinal cord stimulation (SCS) on MCS was also examined and compared with that of DBS. METHODS: One hundred seven patients in VS and 21 patients in MCS were evaluated neurologically and electrophysiologically over 3 months after the onset of brain injury. Among the 107 VS patients, 21 were treated by DBS. Among the 21 MCS patients, 5 were treated by DBS and 10 by SCS. RESULTS: Eight of the 21 patients recovered from VS and were able to follow verbal instructions. These eight patients showed desynchronization on continuous electroencephalographic frequency analysis. The Vth wave of the auditory brainstem response and N20 of somatosensory evoked potential were recorded even with a prolonged latency, and pain-related P250 was recorded with an amplitude of more than 7 µV. In addition, DBS and SCS induced a marked functional recovery in MCS patients who satisfied the electrophysiological inclusion criteria. CONCLUSION: DBS for VS and MCS patients and SCS for MCS patients may be useful, when the candidates are selected on the basis of the electrophysiological inclusion criteria. Only 16 (14.9%) of the 107 VS patients and 15 (71.4%) of the 21 MCS patients satisfied the electrophysiological inclusion criteria.

F-wave suppression induced by suprathreshold high-frequency repetitive trascranial magnetic stimulation in poststroke patients with increased spasticity.

OBJECTIVE: High-intensity and high-frequency repetitive transcranial magnetic stimulation (rTMS) of the primary motor cortex was carried out in poststroke patients with increased spasticity, and the changes in F-wave parameters in comparison with M-wave parameters induced by rTMS were examined. METHODS: Ten-hertz rTMS pulses were delivered to the primary motor cortex of the lesion side at 110% intensity of the resting motor threshold, and F-waves were obtained from the first dorsal interosseous muscle. F-waves were recorded before (pre-stim) and immediately after the end of rTMS (post-stim) in poststroke patients. RESULTS: F-wave persistence and F/M Amp.Ratio increased significantly in patients with lesions in upper motor tract as compared with healthy subjects (Wilcoxon rank sum test, p = 0.00023 and p = 0.0073, respectively). After the rTMS application, both F-wave persistence and F/M Amp.Ratio decreased significantly (paired t-test, p = 0.0095 and p = 0.037, respectively). However, the F-wave amplitude did not show a statistically significant variance in poststroke patients. CONCLUSIONS: High-frequency suprathreshold rTMS may suppress the F-waves by enhancing the inhibitory effect on spinal excitability through the corticospinal tract, and F-wave persistence and F/M Amp.Ratio can be used to determine the effect of rTMS on patients with increased spasticity.

On-demand control system for deep brain stimulation for treatment of intention tremor.

OBJECTIVES: Intention tremor becomes evident only when patients intend to move their body and is characterized by dysmetria. We have developed an on-demand control system that triggers the switching on/off of deep brain stimulation (DBS) instantly for the control of intention tremor. MATERIAL AND METHODS: We used surface electrodes for the recording of electromyographic (EMG) activity, and the power of EMG activity was analyzed instantly employing the fast Fourier transform. The on-demand control system switched on DBS when only the power of tremor frequency exceeded the on-trigger threshold, and the system switched off DBS when the total power of EMG activity decreased below the off-trigger threshold. RESULTS: The on-demand control system triggered the switching on/off of DBS accurately, and controlled intention tremor completely. Our on-demand control system is small and portable, and suitable for clinical use. CONCLUSIONS: The on-demand control system for DBS is useful for controlling intention tremor and may decrease the incidence of tolerance to DBS and may be a powerful tool for various applications of neuromodulation therapy.

Fatal hemorrhage from AVM after DBS surgery: case report.

OBJECTIVES: Intracranial hemorrhage is a crucial complication of deep brain stimulation (DBS) surgery. The bleeding caused by mechanical tissue injury due to microelectrode and/or DBS electrode lead insertion has been well studied. However, hemorrhage caused by a congenital underlying disease such as vascular malformation has not been examined carefully. MATERIALS AND METHODS: We encountered a case of intracerebral hemorrhage from arteriovenous malformation (AVM) after DBS surgery. Preoperative magnetic resonance (MR) imaging did not show any abnormality in the patient. Computed tomography (CT) images taken immediately after the surgery did not show any intracranial hematoma and other abnormal findings. However, the patient did not recover from the general anesthesia, and hemorrhage in the left occipital lobe was detected by CT performed a day after the surgery. The location of the hematoma was markedly distant from the trajectory of DBS leads. Evacuation of the hematoma under general anesthesia was immediately performed. RESULTS: As an intraoperative finding, we noted the presence of abnormal vessels inside the hematoma in the occipital lobe. Tissue specimens including the abnormal vessels were obtained for histopathological analysis, results of which led to the diagnosis was AVM. CONCLUSION: Despite its low incidence, we would like to advise that such a type of hemorrhage could occur and measures should be taken to prevent its occurrence as much as possible. Preoperative detection of abnormal vessels by MR angiography and/or CT angiography might be helpful. Moreover, paying close attention to the possible leakage of cerebrospinal fluid during surgery might be important.

[The indication of DBS in Parkinosn's disease (from a neurosurgical standpoint)].

It is obvious that deep brain stimulation (DBS) is one of the useful treatment choices for progressive Parkinson disease (PD). The main targets for DBS for PD are the thalamic Vim nucleus, globus pallidus interna (GPi), and subthalamic nucleus (STN). Vim-DBS is useful for tremor but not very effective for other Parkinson symptoms. Therefore, presently, STN and GPi are the common targets for DBS for PD. Diminishing the dose of anti-PD drugs is possible usually only after STN-DBS. However, no evident differences in the effect between STN-DBS and GPi-DBS are noted in the majority of studies. Appropriate indication should be decided on the basis of individual target's feature. Dopa responsiveness is a very important factor when considering the operative indications for both STN-DBS and GPi-DBS. CAPSIT protocol is usually used to evaluate the dopa responsiveness. DBS is considered to be characterized by the bottom-up and substitution effects. The disappearance of wearing-off is expected owing to the bottom-up effect and the disappearance of the side effects of anti-PD drugs is expected owing to the substitution effect. Age at surgery, duration of PD, and degree of dopa responsiveness are important factors for outcome prediction. On the other hand, the rate of complications such as cognitive decline, psychosis, and intracranial hemorrhage is relatively high in elderly patients.

Spinal cord stimulation for treatment of patients in the minimally conscious state.

Minimally conscious state (MCS) is characterized by inconsistent but clearly discernible behavioral evidence of consciousness, and can be distinguished from coma and the vegetative state (VS). Ten MCS patients were evaluated neurologically and electrophysiologically over 3 months after the onset of brain injury, and were treated by spinal cord stimulation (SCS). A flexible four-contact, cylinder electrode was inserted into the epidural space of the cervical vertebrae, and placed at the C2-C4 levels. Stimulation was applied for 5 minutes every 30 minutes during the daytime at an intensity that produced motor twitches of the upper extremities. We used 5 Hz for SCS, considering that the induced muscle twitches can be a useful functional neurorehabilitation for MCS patients. Eight of the 10 MCS patients satisfied the electrophysiological inclusion criteria, which we proposed on the basis of the results of deep brain stimulation for the treatment of patients in the VS. Seven patients recovered from MCS following SCS therapy, and were able to carry out functional interactive communication and/or demonstrate the functional use of two different objects. Cervical SCS increased cerebral blood flow (CBF) diffusely in the brain, and CBF increased by 22.2% during the stimulation period compared with CBF before stimulation in MCS patients (p < 0.0001, paired t-test). Five-Hz cervical SCS could increase CBF and induce muscle twitches of the upper extremities. This SCS therapy method may be suitable for treating MCS.

Effect of subthalamic nucleus deep brain stimulation on the autonomic nervous system in Parkinson's disease patients assessed by spectral analyses of R-R interval variability and blood pressure variability.

OBJECTIVE: Autonomic nervous system impairment is an untoward symptom that is typically observed in advanced Parkinson's disease (PD) patients. However, details of the effects of subthalamic nucleus deep brain stimulation (STN-DBS) on the autonomic nervous system remain unclear. METHODS: Twenty-eight patients with advanced PD (12 males and 16 females) who underwent bilateral STN-DBS and 13 age-matched healthy controls were included in this study. We analyzed the dynamic cardiovascular autonomic function regulating the R-R interval and blood pressure by spectral and transfer function analyses of cardiovascular variability before and after STN-DBS. RESULTS: Vagally mediated arterial-cardiac baroreflex function improved after STN-DBS compared to that before STN-DBS (p < 0.05). However, there were no statistically significant differences in the results of the comparison of vagally mediated arterial-cardiac baroreflex function between on-stimulation and off-stimulation. CONCLUSIONS: The vagal component in cardiac autonomic dysfunction associated with PD is expected to improve after STN-DBS. We considered that the patients improved their lifestyle; in particular, increasing the amount of exercise by STN-DBS and the best pharmachological treatment may have positive effects on parasympathetic activities.

Subthalamic nucleus stimulation for attenuation of pain related to Parkinson disease.

OBJECT: The objective of this study was to evaluate the efficacy of chronic subthalamic nucleus (STN) stimulation for alleviating pain related to Parkinson disease (PD). METHODS: Among 163 consecutive patients undergoing STN stimulation, 69 were identified as experiencing pain preoperatively that was related to their PD. All 69 patients suffering from pain were followed up prospectively for 12 months after surgery. All patients described the severity of their pain according to a visual analog scale (VAS) preoperatively and at 2 weeks, 6 months, and 12 months postoperatively. Pain unrelated to PD was not studied. RESULTS: Several types of pain related to PD, the categories of which were based on a modification of 2 previous classifications (Ford and Honey), can occur in such patients: 1) musculoskeletal pain, 2) dystonic pain, 3) somatic pain exacerbated by PD, 4) radicular/peripheral neuropathic pain, and 5) central pain. The overall mean VAS score was significantly decreased postoperatively by 75% and 69% at 2 weeks and 6 months, respectively (p < 0.001). The mean VAS score at 12 months was also decreased by 80%, but 6 instances of pain (3 reports of somatic back pain and 3 reports of radicular/peripheral neuropathic pain) required additional spinal surgery to alleviate the pain severity. The results were analyzed using the Wilcoxon signed-rank test and demonstrated a significant reduction in VAS scores at all follow-up assessments (p < 0.001). Musculoskeletal pain and dystonic pain were well alleviated by STN stimulation. In contrast, somatic pain exacerbated by PD and peripheral neuropathic pain originating from lumbar spinal diseases, such as spondylosis deformans and/or canal stenosis, often deteriorated postoperatively despite attenuation of the patients' motor disability. Patients with central pain were poor responders. CONCLUSIONS: This study found that STN stimulation produced significant improvement of overall pain related to PD in patients with advanced PD, and the efficacy continued for at least 1 year. The present results indicate that musculoskeletal pain and dystonic pain responded well to STN stimulation, but patients with back pain (somatic pain) and radicular/peripheral neuropathic pain originating from spinal disease have a potential risk for postoperative deterioration of their pain.

Changes in motor function induced by chronic motor cortex stimulation in post-stroke pain patients.

BACKGROUND: In well-designed multicenter studies, the protocol of continuing motor cortex stimulation (MCS) temporarily for 3-6 weeks was employed with rehabilitation therapy, and these studies showed some recovery of motor weakness in post-stroke patients. OBJECTIVES: We aimed to clarify the effects of long-term MCS and the optimal stimulation conditions to improve motor weakness in post-stroke patients. METHODS: We applied chronic MCS in 6 post-stroke pain patients with motor weakness. We then examined the correlation between the duration of daily MCS applied over 6 months and motor function assessed on the basis of the Fugl-Meyer Assessment (FMA) score of the patients. RESULTS: In the 6 patients with motor weakness, the FMA score of the upper extremity increased in 4 patients who underwent daily MCS for less than 4 h. On the other hand, 2 patients who continued excessive MCS to control their complicating post-stroke pain showed decreased FMA scores and worsened motor function owing to their increased rigidity and/or spasticity. These 2 patients recovered their motor function after their daily MCS was restricted to less than 4 h. CONCLUSIONS: These findings indicate that MCS could be a new therapeutic approach to improving motor performance after stroke by attenuating rigidity and/or spasticity. However, it may be important to define the appropriate number of hours and conditions of daily MCS.