Pallidal deep brain stimulation for patients with myoclonus-dystonia without SGCE mutations.

BACKGROUND: Pallidal deep brain stimulation (GPi-DBS) is effective for treating myoclonus and dystonia caused by SGCE mutations (DYT-SGCE, DYT11). However, it is unknown whether GPi-DBS is effective for the treatment of myoclonus-dystonia which is not associated with the SGCE gene mutations. In this study, we investigated the efficacy of GPi-DBS in treating myoclonus-dystonia in SGCE mutation-negative cases. METHODS: Three patients with myoclonus-dystonia without SGCE mutations who underwent GPi-DBS were evaluated preoperatively and 6 months postoperatively using the Unified Myoclonus Rating Scale (UMRS) and Fahn-Marsden Dystonia Rating Scale (FMDRS) for myoclonus and dystonia, respectively. In two of the three patients, myoclonus was more evident during action. Myoclonus was predominant at rest in the other patient, and he was unaware of his dystonia symptoms. The results were compared with those of the four DYT-SGCE cases. RESULTS: The mean UMRS score in patients with myoclonus-dystonia without SGCE mutations improved from 61.7 to 33.7 pre- and postoperatively, respectively, and the mean FMDRS score improved from 7.2 to 4.5. However, the degree of improvement in myoclonus-dystonia in patients without SGCE mutations was inferior to that in patients with DYT-SGCE (the UMRS score improved by 45% and 69%, respectively). CONCLUSIONS: GPi-DBS is effective for treating myoclonus-dystonia in patients with and without SGCE mutations. GPi-DBS should be considered as a treatment option for myoclonus-dystonia without SGCE mutations.

Visual fixation suppression of caloric nystagmus in progressive supranuclear palsy - A comparison with Parkinson's disease.

BACKGROUND: Impairment of visual fixation suppression (VS) in progressive supranuclear palsy (PSP) is not well documented. OBJECTIVE: To evaluate the usefulness of impaired VS of caloric nystagmus as an index for differential diagnosis between PSP and Parkinson's disease (PD), which is often difficult, especially in the early stage. METHODS: Subjects comprised 26 PSP patients and 26 PD patients clinically diagnosed at Tokyo Metropolitan Neurological Hospital. We retrospectively investigated VS of caloric nystagmus, horizontal pursuit, saccades, and horizontal optokinetic nystagmus recorded on direct-current-electronystagmography, and neuroradiological findings. RESULTS: The median of the average VS% was 0% and 50.0% in PSP and PD patients, respectively. In PSP, VS was impaired even in the early stage of disease. We found a significant correlation between VS and velocity of saccades or maximum slow phase velocity of optokinetic nystagmus only in PSP patients. PSP patients with atrophy of the subthalamic nucleus or with decreased blood flow in the frontal lobe showed significantly more severe impairment of VS. CONCLUSIONS: VS may be a useful biomarker to differentiate patients with PSP from those with PD. Cerebellar networks that connect with the cerebral cortex and basal ganglia may contribute to impaired VS of caloric nystagmus in PSP.

Degeneration of nigrostriatal dopaminergic neurons in the early to intermediate stage of dementia with Lewy bodies and Parkinson's disease.

OBJECTIVE: To investigate differences in nigrostriatal dopaminergic neuron degeneration between dementia with Lewy bodies (DLB) and Parkinson's disease (PD) in the early to intermediate stage of these diseases. METHODS: An integrative neuroimaging analysis was developed using 3-Tesla neuromelanin-sensitive MRI and 123I-FP-CIT dopamine transporter SPECT, and the relationship and laterality of three variables, including neuromelanin-related contrast in the substantia nigra (NRCSN) and locus coeruleus (NRCLC) and the specific binding ratio (SBR) in the striatum, were examined in detail. Patients with DLB and PD and control subjects (n = 29, 52, and 18, respectively) were enrolled. RESULTS: A significantly greater decrease in the SBR in the bilateral hemispheres was observed in DLB than in PD. After adjusting for the interhemispheric asymmetry in neuromelanin-related MRI contrast by using the Z-score, linear regression between the NRCSN and SBR was performed for the most-affected/least-affected sides of the hemispheres as defined by the interhemispheric differences in each variable (SBR, NRCSN, standardized [SBR + NRCSN]). In DLB, the highest, albeit statistically non-significant, correlation was observed in the SBR-based, most-affected side. In PD, the highest correlation was observed in the (SBR + NRCSN)-based, most-affected side, which approximated the value of the clinically-defined, most-affected side. A non-significant correlation was observed only in the (SBR + NRCSN)-based or clinically-defined, least-affected side. CONCLUSION: Loss of the soma and presynaptic terminals may occur independently in DLB with a large decrease in the presynaptic terminals. The close relationship observed between the degeneration of the soma and presynaptic terminals suggested that axon degeneration may dominate in PD.

[Functional (Psychogenic) Movement Disorder Focusing on Involuntary Movements: A Review].

Functional neurological disorders differ from malingering/factitious disorders and are diagnosed based solely on careful history taking and neurological evaluation. Some clinical characteristics, including distractibility, entrainability, and variability are important to identify the positive physical signs that indicate functional alterations. Thorough investigations are not essential to exclude organic pathologies, whereas electrophysiological and radiological findings are sometimes useful. Neurologists play an important role when they explain the diagnosis to the patient. The explanation itself may be therapeutic, when delivered successfully and may help patients to understand the nature and mechanisms underlying their movement disorder. A multidisciplinary team approach, including coordination between rehabilitation therapists and psychotherapists may produce positive treatment outcomes, particularly in movement disorder centers. In this article, we discuss some functional neurological disorders, including those in patients with functional movement disorders (involuntary movements) together with video presentations.

Therapeutic Effects of Quetiapine and 5-HT1A Receptor Agonism on Hyperactivity in Dopamine-Deficient Mice.

Some diseases that are associated with dopamine deficiency are accompanied by psychiatric symptoms, including Parkinson's disease. However, the mechanism by which this occurs has not been clarified. Previous studies found that dopamine-deficient (DD) mice exhibited hyperactivity in a novel environment. This hyperactivity is improved by clozapine and donepezil, which are used to treat psychiatric symptoms associated with dopamine deficiency (PSDD). We considered that DD mice could be used to study PSDD. In the present study, we sought to identify the pharmacological mechanism of PSDD. We conducted locomotor activity tests by administering quetiapine and drugs that have specific actions on serotonin (5-hydroxytryptamine [5-HT]) receptors and muscarinic receptors. Changes in neuronal activity that were induced by drug administration in DD mice were evaluated by examining Fos immunoreactivity. Quetiapine suppressed hyperactivity in DD mice while the 5-HT1A receptor antagonist WAY100635 inhibited this effect. The number of Fos-positive neurons in the median raphe nucleus increased in DD mice that exhibited hyperactivity and was decreased by treatment with quetiapine and 5-HT1A receptor agonists. In conclusion, hyperactivity in DD mice was ameliorated by quetiapine, likely through 5-HT1A receptor activation. These findings suggest that 5-HT1A receptors may play a role in PSDD, and 5-HT1A receptor-targeting drugs may help improve PSDD.

Dystonic Tremor in Adult-onset DYT-KMT2B.

KMT2B-related dystonia (DYT28, DYT-KMT2B) is an inherited dystonia that generally begins in the lower limbs during childhood and evolves into generalized dystonia. We herein report a case of adult-onset DYT28 with dystonic tremor. A 27-year-old woman initially displayed right upper limb and cervical tremors over the course of 1 year. A neurological examination also revealed cervical and lower limb dystonia. Although the disease generally develops during childhood, we diagnosed the woman with DYT28, as genetic testing revealed a mutation in KMT2B. Adult-onset patients with DYT28 might also show uncommon symptoms as well as DYT-TOR1A (DYT1).

Is Generalized and Segmental Dystonia Accompanied by Impairments in the Dopaminergic System?

Background: The pathogenesis of dystonia is remarkably diverse. Some types of dystonia, such as DYT5 (DYT-GCH1) and tardive dystonia, are related to dysfunction of the dopaminergic system. Furthermore, on pathological examination, cell loss in the substantia nigra (SN) of patients with dystonia has been reported, suggesting that impaired dopamine production may be involved in DYT5 and in other types of dystonia. Objectives: To investigate functional dopaminergic impairments, we compared patients with dystonia and those with Parkinson's disease (PD) with normal controls using neuromelanin-sensitive magnetic resonance imaging (NM-MRI) and dopamine transporter single photon emission computed tomography (DAT SPECT). Methods: A total of 18, 18, and 27 patients with generalized or segmental dystonia, patients with PD, and healthy controls, respectively, were examined using NM-MRI. The mean area corresponding to NM in the SN (NM-SN) was blindly quantified. DAT SPECT was performed on 17 and eight patients with dystonia and PD, respectively. The imaging data of DAT SPECT were harmonized with the Japanese database using striatum phantom calibration. These imaging data were compared between patients with dystonia or PD and controls from the Japanese database in 256 healthy volunteers using the calibrated specific binding ratio (cSBR). The symptoms of dystonia were evaluated using the Fahn-Marsden Dystonia Rating Scale (FMDRS), and the correlation between the results of imaging data and FMDRS was examined. Results: The mean areas corresponding to NM in the SN (NM-SN) were 31 ± 4.2, 28 ± 3.8, and 43 ± 3.8 pixels in patients with dystonia, PD, and in healthy controls, respectively. The mean cSBRs were 5 ± 0.2, 2.8 ± 0.2, 9.2 (predictive) in patients with dystonia, PD, and in healthy controls, respectively. The NM-SN area (r = -0.49, p < 0.05) and the cSBR (r = -0.54, p < 0.05) were inversely correlated with the FMDRS. There was no significant difference between the dystonia and PD groups regarding NM-SN (p = 0.28). In contrast, the cSBR was lower in patients with PD than in those with dystonia (p < 0.5 × 10-6). Conclusions: Impairments of the dopaminergic system may be involved in developing generalized and segmental dystonia. SN abnormalities in patients with dystonia were supposed to be different from degeneration in PD.

PLA2G6 variants associated with the number of affected alleles in Parkinson's disease in Japan.

This study aimed to evaluate genotype-phenotype correlations of Parkinson's disease (PD) patients with phospholipase A2 group V (PLA2G6) variants. We analyzed the DNA of 798 patients with PD, including 78 PD patients reported previously, and 336 in-house controls. We screened the exons and exon-intron boundaries of PLA2G6 using the Ion Torrent system and Sanger method. We identified 21 patients with 18 rare variants, such that 1, 9, and 11 patients were homozygous, heterozygous, and compound heterozygous, respectively, with respect to PLA2G6 variants. The allele frequency was approximately equal between patients with familial PD and those with sporadic PD. The PLA2G6 variants detected frequently were identified in the early-onset sporadic PD group. Patients who were homozygous for a variant showed more severe symptoms than those who were heterozygous for the variant. The most common variant was p.R635Q in our cohort, which was considered a risk variant for PD. Thus, the variants of PLA2G6 may play a role in familial PD and early-onset sporadic PD.

Resting-State Pallidal-Cortical Oscillatory Couplings in Patients With Predominant Phasic and Tonic Dystonia.

Pallidal deep brain stimulation (DBS) improves the symptoms of dystonia. The improvement processes of dystonic movements (phasic symptoms) and tonic symptoms differ. Phasic symptoms improve rapidly after starting DBS treatment, but tonic symptoms improve gradually. This difference implies distinct neuronal mechanisms for phasic and tonic symptoms in the underlying cortico-basal ganglia neuronal network. Phasic symptoms are related to the pallido-thalamo-cortical pathway. The pathway related to tonic symptoms has been assumed to be different from that for phasic symptoms. In the present study, local field potentials of the globus pallidus internus (GPi) and globus pallidus externus (GPe) and electroencephalograms from the motor cortex (MCx) were recorded in 19 dystonia patients to analyze the differences between the two types of symptoms. The 19 patients were divided into two groups, 10 with predominant phasic symptoms (phasic patients) and 9 with predominant tonic symptoms (tonic patients). To investigate the distinct features of oscillations and functional couplings across the GPi, GPe, and MCx by clinical phenotype, power and coherence were calculated over the delta (2-4 Hz), theta (5-7 Hz), alpha (8-13 Hz), and beta (14-35 Hz) frequencies. In phasic patients, the alpha spectral peaks emerged in the GPi oscillatory activities, and alpha GPi coherence with the GPe and MCx was higher than in tonic patients. On the other hand, delta GPi oscillatory activities were prominent, and delta GPi-GPe coherence was significantly higher in tonic than in phasic patients. However, there was no significant delta coherence between the GPi/GPe and MCx in tonic patients. These results suggest that different pathophysiological cortico-pallidal oscillations are related to tonic and phasic symptoms.

Topographic anatomy of the subthalamic nucleus localized by high-resolution human brain atlas superimposing digital images of cross-sectioned surfaces and histological images of microscopic sections from frozen cadaveric brains.

Despite the recent advent of neuro-radiographic techniques, creating a 'perfect' human brain atlas providing precise and consistent images with minimal distortion is practically difficult. In this study, we created a new human brain atlas from cadaveric brains with serial sections of 50 µm thickness covering the entire basal ganglia. Human cerebral hemispheres were obtained from 10 donated cadavers and fixed in 10% formalin solution, cut in a block measuring 50 mm × 30 mm × 50 mm around the midpoint of the anterior and posterior commissures and frozen at -40 °C. Each block was cut into 50-µm-thick sections on the freezing microtome and the cross-sectioned surface was photographed. Simultaneously, every 10th slice from one sagittal hemisphere was sampled and stained using the Kluver-Barrera method. Prepared slides were photographed under light microscopy, and data from digital images of the cross-sectioned surface (DICSS) and digital images from microscopic sections (DIMS) were processed. Gray areas on DICSS largely represented areas of dense cellularity, and around subthalamic nucleus (STN), the zona incerta and field of Forel were clearly distinguishable on the anterosuperior side, as was the substantia nigra on the caudal side. DICSS successfully delineated the anatomical structure identical to the STN and surrounding contiguous nuclei. This new brain atlas will allow elucidation of anatomy that cannot be clearly disclosed from modern radiographic imaging or is very difficult to analyze with spatially inconsistent histological sections, and will contribute to further progress in anatomical studies of the human basal ganglia.

Frequency-Specific Synchronization in the Bilateral Subthalamic Nuclei Depending on Voluntary Muscle Contraction and Relaxation in Patients with Parkinson's Disease.

The volitional control of muscle contraction and relaxation is a fundamental component of human motor activity, but how the processing of the subcortical networks, including the subthalamic nucleus (STN), is involved in voluntary muscle contraction (VMC) and voluntary muscle relaxation (VMR) remains unclear. In this study, local field potentials (LFPs) of bilateral STNs were recorded in patients with Parkinson's disease (PD) while performing externally paced VMC and VMR tasks of the unilateral wrist extensor muscle. The VMC- or VMR-related oscillatory activities and their functional couplings were investigated over the theta (4-7 Hz), alpha (8-13 Hz), beta (14-35 Hz), and gamma (40-100 Hz) frequency bands. Alpha and beta desynchronizations were observed in bilateral STNs at the onset of both VMC and VMR tasks. On the other hand, theta and gamma synchronizations were prominent in bilateral STNs specifically at the onset of the VMC task. In particular, just after VMC, theta functional coupling between the bilateral STNs increased, and the theta phase became coupled to the gamma amplitude within the contralateral STN in a phase-amplitude cross-frequency coupled manner. On the other hand, the prominent beta-gamma cross-frequency couplings observed in the bilateral STNs at rest were reduced by the VMC and VMR tasks. These results suggest that STNs are bilaterally involved in the different performances of muscle contraction and relaxation through the theta-gamma and beta-gamma networks between bilateral STNs in patients with PD.

Bilateral coherence between motor cortices and subthalamic nuclei in patients with Parkinson's disease.

OBJECTIVE: It has been suggested that abnormal synchronization and oscillation of neuronal activity in the subthalamic nucleus (STN) is associated with sensorimotor dysfunction in Parkinson's disease (PD). We investigated the bilateral subcortico-cortical functional coupling in PD patients. METHODS: We simultaneously recorded local field potentials from the bilateral STN using electrodes inserted for deep brain stimulation and electroencephalograms from the bilateral motor cortices (MCx) in 11 patients at rest, and analyzed their coherences and causalities. RESULTS: Significant coherence in the sub-beta and beta frequency bands was simultaneously observed between the STN and contralateral STN (STN-cSTN), the STN and ipsilateral MCx (STN-iMCx), and the STN and contralateral MCx (STN-cMCx). In each patient, the frequency of the peak STN-cSTN coherence was similar to that of the peak STN-iMCx and STN-cMCx coherence. The causality between the STN and MCx was strongest in the one-way direction from the MCx to the ipsilateral STN. CONCLUSIONS: Abnormal oscillations in the STN in the sub-beta and beta bands were functionally coupled among bilateral STN and MCx at the eigen-frequency in individual patients with PD. SIGNIFICANCE: Synchronized activity through cortico-subcortical transmission may have an important role in the pathophysiology of PD.

An Asian Patient with Myoclonus-Dystonia (DYT11) Responsive to Deep Brain Stimulation of the Globus Pallidus Internus.

We describe the case of a 42-year-old Japanese woman with childhood-onset myoclonus, dystonia, and psychiatric symptoms, including anxiety, phobia, and exaggerated startle response. The diagnosis was confirmed as myoclonus-dystonia (DYT11) by identifying a mutation in the gene encoding ε -sarcoglycan. Interestingly, while motor-related symptoms in DYT11 generally improve with alcohol ingestion, the patient's symptoms were exacerbated by alcohol intake. Her severe and medically intractable symptoms were alleviated by bilateral deep brain stimulation of the globus pallidus internus, with myoclonus and dystonia scores showing 70% improvement after the surgery compared to presurgical scores. This is the first report of a genetically confirmed case of DYT11 in Japan. This paper together with other recent reports collectively demonstrates that DYT11 patients are distributed worldwide, including Asia. Thus, a diagnosis of DYT11 should be considered when clinicians encounter a patient with childhood-onset myoclonus and/or dystonia with psychiatric symptoms, regardless of ethnic background.

[An autopsy case of corticobasal degeneration with notable early onset apraxia: a case report and literature review focused on apraxia].

We report the autopsy case of a 74-year-old woman. Onset of gait disturbance and left-side dominant bilateral motor disturbance in the patient led to bilateral progressive apraxia. This was associated with a decline in motor imagery, right-side dominant atrophy of the central sulcus region, and a decrease in cerebral blood flow during illness. She died of respiratory failure that had progressively worsened over a 9-year period. Pathologically, she exhibited right-side dominant cerebral atrophy; neuronal loss, gliosis, and astrocytic plaques were mainly present in the frontal lobe. She was subsequently diagnosed with corticobasal degeneration (CBD). The premotor and primary motor areas revealed marked degeneration; in addition, severe myelin pallor was observed in these regions, and it was suggested that such pathological features were responsible for the apraxia. We believe the present case is valuable since very few reports have provided a detailed description of clinicopathological apraxia in association with CBD.

Mechanisms of unilateral STN-DBS in patients with Parkinson's disease : a PET study.

Bilateral symptoms and signs of Parkinson's disease (PD) are often improved by unilateral subthalamic nucleus deep brain stimulation (STN-DBS). However, the mechanism for such bilateral effects is unknown. This study was intended to examine effects of unilateral STN-DBS using positron emission computed tomography (PET) and to elucidate mechanisms for bilateral improvement achieved by unilateral stimulation.We conducted (18)F-fluorodeoxyglucose ((18)FDG) and (18)F-fluorodopa ((18)F-DOPA ) PET scans in PD patients whose bilateral limb symptoms and axial symptoms were improved by unilateral DBS. Two scans were performed in each PET study: when DBS was on and off. We compared those images using statistic parametric mapping (SPM) 99.The significant clinical improvement obtained by unilateral DBS was shown as improvements in bilateral motor limb, axial, and gait subscores of the Unified PD Rating Scale (UPDRS). Moreover, (18)FDG PET revealed significant metabolic increases in the ipsilateral ventrolateral thalamic areas and metabolic decrease at the contralateral globus pallidus interna (GPi). In contrast, (18)F-DOPA PET showed no significant differences between DBS on and off.Ipsilateral thalamic activation might induce ipsilateral motor cortical activation, which explains the improvement of contralateral limb symptoms. Furthermore, deactivation of the contralateral GPi might disinhibit the thalamus and contralateral motor cortex, which explains reduction of ipsilateral limb symptoms. These results suggest the mechanisms for bilateral improvement achieved by unilateral DBS.

[Unilateral subthalamic stimulation for early-stage Parkinson's disease].

According to evidenced-based criteria, surgical treatment with subthalamic stimulation is indicated for advanced Parkinson's disease with severe motor complications. Currently, the treatment is indicated for patients in whom medical treatment has failed even if the patient is still in an early stage. This study investigated the efficacy and safety of unilateral subthalamic stimulation for patients with early-stage Parkinson's disease. We evaluated the Unified Parkinson's Disease Rating Scale (UPDRS) and the Schwab England ADL score before and 6 months after this treatment in 6 patients with early-stage Parkinson's disease demonstrating predominantly unilateral parkinsonian symptoms. We implanted a stimulation electrode (model 3387 or 3389) unilaterally on the side showing dominate symptoms, using both MRI and electrophysiological guidance. Six months after the beginning of stimulation, the UPDRS motor score without medication was improved by 64% and the Schwab England ADL score was improved by 23%. There were no adverse events except for asymptomatic intra-ventricular hemorrhage in one patient. Unilateral subthalamic stimulation is a useful treatment for patients with early-stage Parkinson's disease showing predominantly unilateral parkinsonian symptoms. However, long-term results of subthalamic stimulation for early-stage patients remain unclear.

A clinical and genetic study in a large cohort of patients with spinocerebellar ataxia type 6.

In order to clarify the clinical and genetic features of SCA6, we retrospectively analyzed 140 patients. We observed an inverse correlation between the age of onset and the length of the expanded allele, and also between the age of onset and the sum of CAG repeats in the normal and the expanded alleles. The ages of onset of four homozygous patients correlated better with the sum of CAG repeats in both alleles rather than with the expanded allele calculated from heterozygous SCA6 subjects. Clinically, unsteadiness of gait was the main initial symptom, followed by vertigo and oscillopsia, and cerebellar signs were detected in nearly 100% of the patients. In contrast, extracerebellar signs were relatively mild and infrequent. The results of neuro-otological examination performed in 22 patients suggested the purely cerebellar abnormalities of ocular movements in nature. There was a close relationship between downbeat positioning nystagmus (DPN) and positioning vertigo, which became more common in the later stage. We conclude that total number of CAG repeat-units in both alleles is a good parameter for assessment of age of onset in SCA6 including homozygous patients. In addition, clinical and neuro-otological examinations suggested that SCA6 is a disease with predominantly cerebellar dysfunction.

[Variance in effects of subthalamic nucleus stimulation].

Chronic stimulation of subthalamus nucleus (STN) is effective in treating severe motor fluctuation and levodopa induced dyskinesia as well as parkinsonian motor symptoms. The improvement of peak-dose/diphasic dyskinesias of STN stimulation is considered to be due to the decrease in the daily dosage of antiparkinsonian drugs. However one report pointed out that STN stimulation improved directly levodopa induced dyskinesia. Moreover the timing of the improvement for levodopa induced dyskinesia is not yet obvious. In the present study, we have assessed variance in the latency of improvement of levodopa induced dyskinesia due to STN stimulation. In addition, we would clarify an issue which cite of STN stimulation improved parkinsonian symptoms and motor complication (motor dyskinesias and motor fluctuation). We have studied seven patients diagnosed with advanced idiopathic Parkinson's disease with motor fluctuations and levodopa induced dyskinesias. Before and after the implantation of stimulating electrode, patients were assessed by the Unified Parkinson's Disease Rating Scale and % 'OFF' motor state. The dosage of the antiparkinsonian medication was not modified for one month prior to implantation. Following implantation, dosage of the medication and strength of stimulation was adjusted, if necessary. Symptoms of motor fluctuation and dyskinesia improved in all patients six month after surgery. The mean off-time duration and dyskinesia disability improved compared with presurgical conditions. However, the time course of the improvement of dyskinesias was not the same among patients. Contralateral limb dyskinesias in three patients improved immediately after the stimulation without modification of medication. In contrast, the stimulation worsened contralateral limb dyskinesias in other three patients immediately following the surgery. In two of the three patients, dyskinesias gradually improved within one month after surgery without reducing the dosage of medication. Dyskinesias of the other patient improved following a reduction in the dosage of medication one month after the surgery. Improvement of parkinsonian symptoms of the patients with longer latency of stimulation effect for dyskinesias was better than that of the patients with shorter latency. Stimulation cite of the former group appeared to locate more central than that of the latter group. Latency and strength of the effects of STN stimulation are variable.