An investigation into the effects and prognostic factors of cognitive decline following subthalamic nucleus stimulation in patients with Parkinson's disease.

We retrospectively investigated the effects of subthalamic nucleus stimulation (STN-DBS) on new postoperative onset of cognitive decline and prognostic factors for advanced Parkinson's disease (PD). We studied 39 PD patients who had received bilateral STN-DBS. Clinical symptoms, cognitive function, psychiatric function, and health-related quality of life (HRQOL) were assessed before and six months after surgery. Based on the results of neuropsychological examinations six months after the surgery, the subjects were divided into those with and those without cognitive decline. We compared pre- and post-operative assessments between the two groups. Prognostic factors were investigated using multiple logistic regression analyses. Seven patients had cognitive decline six months after the operation (17.9%); they were significantly older than those without cognitive decline. Preoperative neuropsychological examinations revealed impairments in language and executive function. No differences were found in clinical symptoms. Patients with cognitive decline had significantly worse apathy scale scores. The HRQOL revealed significant declines in the Mental Component Summary (MCS), vitality, and mental health (MH) domains. Postoperative comparisons revealed novel significant differences in activities of daily living in the "on" and "off" states and in daytime drowsiness. Preoperative differences seen in the MCS and vitality indices were no longer present. Word fluency, and apathy scale and MH scores were independent preoperative prognostic factors for cognitive decline. New postoperative onset of cognitive decline due to STN-DBS affected activities of daily living and psychiatric function. Preoperative non-motor symptoms may be prognostic factors for new onset of cognitive decline.

[Case of enlargement of an intradiploic epidermoid cyst by a head contusion].

We report a case of enlargement of a intradiploic epidermoid cyst following head trauma in a 19-year-old man. The patient had a swelling on the right side of his forehead from the time of his birth. He sustained a bruise in this region when he was 15 years old, following which the swelling gradually enlarged. When the diameter of the mass increased to 5 cm, he visited our hospital. Computed tomography (CT) scan of the head showed a subcutaneous mass of low density extending from the diploe to the outer tables of the skull. Magnetic resonance imaging (MRI) showed a hyperintense mass in both T1- and T2-weighted images. During the operation, we found a tumor that was intradiploic and had a thin capsule. The effusion from the tumor resembled an old hematoma, and the tumor did not involve the paranasal sinuses. We concluded the operation by performing cranioplasty using artificial bone. Histological examination revealed that the thin capsule consisted of stratified squamous epithelium and ciliated epithelium. Needle-like cholesterol crystals and hemosiderosis were seen shown in the granulation-like tissue. On the basis of these findings, we diagnosed the mass to bean intradiploic epidermoid cyst and thought that it might have grown following head trauma associated with chronic hemorrhage. This paper reviews the differential diagnosis and pathologic findings of the intradiploic epidermoid cyst along with some previously published cases.

[Case report of lumbar discal cyst].

The authors describe a rare case of lumbar discal cyst which produced manifestations similar o lumbar disc herniation. A 33-year-old man, who had had a crick in the back 3 months previously, suffered from severe low back and right lower-extremity pain. The neurological examination showed the L5 radiculopathy through the positive straight leg-raising test, no motor weakness nor sensory disturbance with normal reflexes. Magnetic resonance imaging demonstrated an oval shaped extradural lesion with a low signal intensity on T1-weighted images and a high signal intensity on T2-weighted images. Additionally, the surrounding rim of the cyst was enhanced with the addition of Gd-DTPA. As we diagnosed a lumbar discal cyst with severe symptoms, the patient received emergent surgery. The symptom disappeared immediately after surgery. This case implies that early surgery for discal cyst may be an effective means to obtain release from symptoms.

Attenuation of fluctuating striatal synaptic dopamine levels in patients with Parkinson disease in response to subthalamic nucleus stimulation: a positron emission tomography study.

OBJECT: The "wearing-off" phenomenon often hampers the treatment of Parkinson disease (PD). Although deep brain stimulation (DBS) of the subthalamic nucleus (STN) is known to ameliorate the wearing-off phenomenon, the mechanism by which it does this remains unclear. As part of an inquiry into the mechanism of STN DBS, the authors measured synaptic dopamine levels in the striatum by performing positron emission tomography (PET) with [11C]raclopride. METHODS: Three patients with PD who were experiencing the wearing-off phenomenon underwent PET scanning before and after DBS of the STN. The clinical features in these patients were evaluated by applying the Hoehn and Yahr, United Parkinson's Disease Rating, and Schwab and England Activities of Daily Living Scales. Before and after surgery, PET scans were obtained using [11C]raclopride prior to and 1 hour following an oral administration of levodopa. Regions of interest for the [11C]raclopride binding potential (RacloBP) were set in the bilateral putamen and the caudate nucleus. All clinical scores were dramatically improved postoperatively. Deep brain stimulation of the STN reduced the baseline RacloBP in both the putamen and caudate nucleus, but the differences between the pre- and postoperative levels were insignificant. Before DBS of the STN, the levodopa administration significantly reduced RacloBP in the putamen (p < 0.0001). Postoperatively the drug-induced reduction in RacloBP became statistically insignificant. The drug-induced increase in synaptic dopamine concentrations in the putamen preoperatively was estimated to be approximately four times higher than that after surgery (p < 0.01). The drug-induced RacloBP change in the caudate nucleus was similar to that in the putamen, although the magnitude of the change was lower (p < 0.005). The drug-induced increase in the caudate nucleus was also reduced postoperatively (p < 0.05). CONCLUSIONS: Deep brain stimulation of the STN induces the stabilization of synaptic dopamine concentrations in the striatum and may attribute to the alleviation of levodopa-related motor fluctuations.

The role of sigma-receptors in levodopa-induced dyskinesia in patients with advanced Parkinson disease: a positron emission tomography study.

OBJECT: Levodopa-induced dyskinesia (LID) in patients with Parkinson disease (PD) mimics acute dystonic reactions induced by antipsychotic agents, possibly mediated by sigma-receptors; however, there are few reports in which the relationship between sigma-receptors and LID in advanced PD is investigated. The binding potential of cerebellar sigma-receptors before and after a pallidal surgery for dyskinesia in patients with advanced PD is assessed. METHODS: Six patients with advanced PD (male/female ratio 3:3, age 56.7 +/- 9.8 years) underwent stereotactic pallidal surgery (two posteroventral pallidotomy procedures and four deep brain stimulation of the globus pallidus internus, including one bilateral case). Clinical features of patients with PD were assessed using Hoehn and Yahr (H & Y) stages, the Unified Parkinson's Disease Rating Scale (UPDRS), and the Schwab and England Activities of Daily Life Scale (S & E). The LID was evaluated by LID severity score. The binding potential of cerebellar sigma-receptors was determined before and after the surgery by 11C-nemonapride positron emission tomoraphy, a specific radioligand for sigma-receptors in the cerebellum. All clinical scores, especially the LID severity score, were dramatically improved after the surgery (p < 0.05). Preoperatively, contralateral cerebellar binding potential was significantly elevated (p < 0.01), and it was reduced after the surgery, but it was still higher than that of healthy volunteers (p < 0.05). The ipsilateral cerebellar binding potential remained unchanged after the surgery. The level of binding potential did not correlate with H & Y stage, UPDRS, or S & E score, but a strong positive correlation was seen between the binding potential and the preoperative LID severity score when the patients were receiving medication (r = 0.893, p < 0.05). CONCLUSIONS: Cerebellar sigma-receptors may potentially involve the genesis of LID in advanced PD.

The impact of stereotactic pallidal surgery on the dopamine D2 receptor in Parkinson disease: a positron emission tomography study.

OBJECT: The aim of this study was to estimate the impact of stereotactic pallidal surgery on the binding potential of dopamine D2 receptors in patients with advanced Parkinson disease (PD). METHODS: Six patients with advanced PD (three men and three women; mean age 56.7 +/- 9.8 years, Hoehn and Yahr stage 3.3 +/- 1.1/3.9 +/- 1.2 [on/off scores], mean +/- standard deviation) underwent stereotactic pallidal surgery. One underwent right posteroventral pallidotomy (PVP), one received left PVP, three were treated with deep brain stimulation (DBS) of the left globus pallidus internus (GPi), and one with bilateral DBS of the GPi. The binding potential of the dopamine D2 receptors of these patients was determined before and after surgery by using positron emission tomography scanning with 11C-nemonapride and it was compared with the value in eight healthy volunteers. The authors also examined whether changes in the D2 receptor binding potential were correlated with the clinical outcome. The clinical symptoms, especially those in the off state, were significantly improved after surgery. Preoperatively, the D2 receptor binding potential in the putamen was elevated by 27% (p < 0.01) and that in the thalamus was 29% lower than that in controls (p < 0.01). The D2 receptor binding potential in the putamen and thalamus returned to control levels after surgery. The preoperative level of the D2 receptor binding potential in the anterior cingulate cortex was comparable to that of controls, but it declined significantly after surgery, whereas the D2 receptor binding potential in other regions of both hemispheres showed no significant changes after surgery. Although the D2 receptor binding potential did not correlate with the Hoehn and Yahr stage, the Schwab and England score, or the Unified PD Rating Scale (UPDRS) score, a positive correlation was seen between the percent improvement rate of the total UPDRS score in the off state and the percentage change of the D2 receptor binding potential in the putamen (r = 0.773, p = 0.0417 according to the Pearson linear correlation). CONCLUSIONS: The altered dopamine D2 receptor binding potential in the putamen might play a crucial role in clinical improvement after PVP or DBS of the GPi in advanced PD.