Delivering the diagnosis of multiple system atrophy: a multicenter survey on Japanese neurologists' perspectives.

BACKGROUND: Multiple system atrophy (MSA) is a progressive, incurable, life-threatening neurodegenerative disease uniquely characterized by the risk of sudden death, which makes diagnosis delivery challenging for neurologists. Empirical studies on breaking a diagnosis of MSA are scarce, with no guidelines currently established. This study aimed to investigate neurologists' current practices and experiences in delivering the diagnosis of MSA. METHODS: We conducted a multicenter online survey and employed a mixed-methods (quantitative and qualitative) study design in which responses to open-ended questions were analyzed qualitatively using critical incident technique. RESULTS: Among the 194 neurologists surveyed, 166 opened the survey (response rate = 85.6%), of whom 144 respondents across various Japanese regions completed the survey. Accordingly, 92.3% and 82.8% of the participating neurologists perceived delivering the diagnosis of MSA and explaining the risk of sudden death as difficult, respectively. Factors independently associated with difficulties in diagnosis delivery included explaining the importance of the family decision making process in life-prolonging treatment, perceived difficulties in delivering information regarding the risk of sudden death, and perceived difficulties in differential diagnosis of MSA. CONCLUSIONS: Our findings showed that the majority of neurologists perceived delivering the diagnosis of MSA and explaining the risk of sudden death as difficult, which could have been associated with the difficulty of breaking the diagnosis of MSA. Difficulty in conveying bad news in MSA are caused by various factors, such as empathic burden on neurologists caused by the progressive and incurable nature of MSA, the need to explain complex and important details, including the importance of the family decision-making process in life-prolonging treatment, difficulty of MSA diagnosis, and communication barriers posed by mental status and cognitive impairment in patients or their family members. Neurologists consider various factors in explaining the risk of sudden death (e.g., patient's personality, mental state, and degree of acceptance and understanding) and adjust their manner of communication, such as limiting their communication on such matters or avoiding the use of the term "sudden death" in the early stages of the disease. Although neurologists endeavor to meet the basic standards of good practice, there is room for the multiple aspects for improvement.

Differentiation between Parkinson's Disease and the Parkinsonian Subtype of Multiple System Atrophy Using the Magnetic Resonance T1w/T2w Ratio in the Middle Cerebellar Peduncle.

Multiple system atrophy with predominant parkinsonism (MSA-P) can hardly be distinguished from Parkinson's disease (PD) clinically in the early stages. This study investigated whether a standardized T1-weighted/T2-weighted ratio (sT1w/T2w ratio) can effectively detect degenerative changes in the middle cerebellar peduncle (MCP) associated with MSA-P and PD and evaluated its potential to distinguish between these two diseases. We included 35 patients with MSA-P, 32 patients with PD, and 17 controls. T1w and T2w scans were acquired using a 1.5-T MR system. The MCP sT1w/T2w ratio was analyzed via SPM12 using a region-of-interest approach in a normalized space. The diagnostic performance of the MCP sT1w/T2w ratio was compared between the MSA-P, PD, and controls. Patients with MSA-P had significantly lower MCP sT1w/T2w ratios than patients with PD and controls. Furthermore, MCP sT1w/T2w ratios were lower in patients with PD than in the controls. The MCP sT1w/T2w ratio showed excellent or good accuracy for differentiating MSA-P or PD from the control (area under the curve (AUC) = 0.919 and 0.814, respectively) and substantial power for differentiating MSA-P from PD (AUC = 0.724). Therefore, the MCP sT1w/T2w ratio is sensitive in detecting degenerative changes in the MCP associated with MSA-P and PD and is useful in distinguishing MSA-P from PD.

Developing Medical Education Curriculum Reform Strategies to Address the Impact of Generative AI: Qualitative Study.

BACKGROUND: Generative artificial intelligence (GAI), represented by large language models, have the potential to transform health care and medical education. In particular, GAI's impact on higher education has the potential to change students' learning experience as well as faculty's teaching. However, concerns have been raised about ethical consideration and decreased reliability of the existing examinations. Furthermore, in medical education, curriculum reform is required to adapt to the revolutionary changes brought about by the integration of GAI into medical practice and research. OBJECTIVE: This study analyzes the impact of GAI on medical education curricula and explores strategies for adaptation. METHODS: The study was conducted in the context of faculty development at a medical school in Japan. A workshop involving faculty and students was organized, and participants were divided into groups to address two research questions: (1) How does GAI affect undergraduate medical education curricula? and (2) How should medical school curricula be reformed to address the impact of GAI? The strength, weakness, opportunity, and threat (SWOT) framework was used, and cross-SWOT matrix analysis was used to devise strategies. Further, 4 researchers conducted content analysis on the data generated during the workshop discussions. RESULTS: The data were collected from 8 groups comprising 55 participants. Further, 5 themes about the impact of GAI on medical education curricula emerged: improvement of teaching and learning, improved access to information, inhibition of existing learning processes, problems in GAI, and changes in physicians' professionality. Positive impacts included enhanced teaching and learning efficiency and improved access to information, whereas negative impacts included concerns about reduced independent thinking and the adaptability of existing assessment methods. Further, GAI was perceived to change the nature of physicians' expertise. Three themes emerged from the cross-SWOT analysis for curriculum reform: (1) learning about GAI, (2) learning with GAI, and (3) learning aside from GAI. Participants recommended incorporating GAI literacy, ethical considerations, and compliance into the curriculum. Learning with GAI involved improving learning efficiency, supporting information gathering and dissemination, and facilitating patient involvement. Learning aside from GAI emphasized maintaining GAI-free learning processes, fostering higher cognitive domains of learning, and introducing more communication exercises. CONCLUSIONS: This study highlights the profound impact of GAI on medical education curricula and provides insights into curriculum reform strategies. Participants recognized the need for GAI literacy, ethical education, and adaptive learning. Further, GAI was recognized as a tool that can enhance efficiency and involve patients in education. The study also suggests that medical education should focus on competencies that GAI hardly replaces, such as clinical experience and communication. Notably, involving both faculty and students in curriculum reform discussions fosters a sense of ownership and ensures broader perspectives are encompassed.

Efficacy and Safety of Ultrahigh-Dose Methylcobalamin in Early-Stage Amyotrophic Lateral Sclerosis: A Randomized Clinical Trial.

Importance: The effectiveness of currently approved drugs for amyotrophic lateral sclerosis (ALS) is restricted; there is a need to develop further treatments. Initial studies have shown ultrahigh-dose methylcobalamin to be a promising agent. Objective: To validate the efficacy and safety of ultrahigh-dose methylcobalamin for patients with ALS enrolled within 1 year of onset. Design, Setting, and Participants: This was a multicenter, placebo-controlled, double-blind, randomized phase 3 clinical trial with a 12-week observation and 16-week randomized period, conducted from October 17, 2017, to September 30, 2019. Patients were recruited from 25 neurology centers in Japan; those with ALS diagnosed within 1 year of onset by the updated Awaji criteria were initially enrolled. Of those, patients fulfilling the following criteria after 12-week observation were eligible for randomization: 1- or 2-point decrease in the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) total score, a percent forced vital capacity greater than 60%, no history of noninvasive respiratory support and tracheostomy, and being ambulatory. The target participant number was 64 in both the methylcobalamin and placebo groups. Patients were randomly assigned through an electronic web-response system to methylcobalamin or placebo. Interventions: Intramuscular injection of methylcobalamin (50-mg dose) or placebo twice weekly for 16 weeks. Main Outcomes and Measures: The primary end point was change in ALSFRS-R total score from baseline to week 16 in the full analysis set. Results: A total of 130 patients (mean [SD] age, 61.0 [11.7] years; 74 men [56.9%]) were randomly assigned to methylcobalamin or placebo (65 each). A total of 129 patients were eligible for the full analysis set, and 126 completed the double-blind stage. Of these, 124 patients proceeded to the open-label extended period. The least square means difference in ALSFRS-R total score at week 16 of the randomized period was 1.97 points greater with methylcobalamin than placebo (-2.66 vs -4.63; 95% CI, 0.44-3.50; P = .01). The incidence of adverse events was similar between the 2 groups. Conclusions and Relevance: Results of this randomized clinical trial showed that ultrahigh-dose methylcobalamin was efficacious in slowing functional decline in patients with early-stage ALS and with moderate progression rate and was safe to use during the 16-week treatment period. Trial Registration: ClinicalTrials.gov Identifier: NCT03548311.

Temporal Changes in Brain Perfusion in a Patient with Myoclonus and Ataxia Syndrome Associated with COVID-19.

Myoclonus and ataxia, with or without opsoclonus, have recently been recognized as a central nervous system syndrome associated with coronavirus disease-2019 (COVID-19). A 52-year-old Japanese man developed myoclonus and ataxia 16 days after the onset of COVID-19. Brain single-photon emission computed tomography (SPECT) revealed hyperperfusion in the cerebellum and hypoperfusion in the cerebral cortices with frontal predominance during the acute stage, which improved over two months. This study indicates that brain perfusion SPECT can be effective in detecting functional alterations in COVID-19-related myoclonus and ataxia.

Sleep-related hypoventilation and hypercapnia in multiple system atrophy detected by polysomnography with transcutaneous carbon dioxide monitoring.

PURPOSE: We aimed to evaluate sleep-related hypoventilation in multiple system atrophy (MSA) using polysomnography (PSG) with transcutaneous partial pressure of carbon dioxide (PtcCO2) monitoring. METHODS: This prospective study included 34 patients with MSA. Motor and autonomic function, neuropsychological tests, PSG with PtcCO2 monitoring, and pulmonary function tests were performed. Sleep-related hypoventilation disorder (SRHD) was defined according to the International Classification of Sleep Disorders, third edition. RESULTS: Nine (27%) of the 34 patients met the diagnostic criteria of SRHD. Twenty-nine (85%) patients had sleep-related breathing disorders based on an Apnea-Hypopnea Index of ≥ 5/h. The patients with MSA and SRHD had a higher arousal index (p = 0.017) and obstructive apnea index (p = 0.041) than those without SRHD. There was no difference in the daytime partial pressure of carbon dioxide in arterial blood or respiratory function between MSA patients with and without SRHD. CONCLUSION: Sleep-related hypoventilation may occur in patients with MSA even with a normal daytime partial pressure of carbon dioxide. This can be noninvasively detected by PSG with PtcCO2 monitoring. SRBD and sleep-related hypoventilation are common among patients with MSA, and clinicians should take this into consideration while evaluating and treating this population.

Recurrent Cerebral Infarcts Associated with Uterine Adenomyosis: Successful Prevention by Surgical Removal.

Hypercoagulability associated with malignant tumors causes thrombosis, termed Trousseau's syndrome, but is rarely associated with benign gynecological tumors, such as myoma and adenomyosis. We herein report a 47-year-old Japanese woman with uterine adenomyosis who developed multiple cerebral infarcts during menstruation. Edoxaban was initially used for prevention but failed to prevent recurrence of thrombosis. However, hysterectomy and bilateral salpingo-oophorectomy resulted in the successful prevention of recurrence of cerebral infarct for five years without antiplatelet or anticoagulant agents. In our patient, the surgical removal of adenomyosis was highly effective for preventing thrombosis in a patient with adenomyosis.

Importance of the Features of Event-Related Potentials Used for a Machine Learning-Based Model Applied to Single-Trial Data during Oddball Task.

In this study, a method for assessing the human state and brain-machine interface (BMI) has been developed using event-related potentials (ERPs). Most of these algorithms are classified based on the ERP characteristics. To observe the characteristics of ERPs, an averaging method using electroencephalography (EEG) signals cut out by time-locking to the event for each condition is required. To date, several classification methods using only single-trial EEG signals have been studied. In some cases, the machine learning models were used for the classifications; however, the relationship between the constructed model and the characteristics of ERPs remains unclear. In this study, the LightGBM model was constructed for each individual to classify a single-trial waveform and visualize the relationship between these features and the characteristics of ERPs. The features used in the model were the average values and standard deviation of the EEG amplitude with a time width of 10 ms. The best area under the curve (AUC) score was 0.92, but, in some cases, the AUC scores were low. Large individual differences in AUC scores were observed. In each case, on checking the importance of the features, high importance was shown at the 10-ms time width section, where a large difference was observed in ERP waveforms between the target and the non-target. Since the model constructed in this study was found to reflect the characteristics of ERP, as the next step, we would like to try to improve the discrimination performance by using stimuli that the participants can concentrate on with interest.

Pareidolia in Parkinson's Disease and Multiple System Atrophy.

Pareidolia is a visual illusion of meaningful objects that arise from ambiguous forms embedded in visual scenes. Previous studies showed that pareidolias are frequently observed in patients with Parkinson's disease (PD) as well as dementia with Lewy bodies. However, whether pareidolias are useful for differentiating PD from other neurodegenerative parkinsonism disorders including multiple system atrophy (MSA) is unclear. The noise pareidolia test (NPT) was performed in 40 and 48 patients with PD and MSA, respectively. A receiver operating characteristic (ROC) curve analysis was used to evaluate sensitivity and specificity. Results of neuropsychological tests were also compared between patients with PD with and without pareidolias. Visual hallucinations were present in none of the subjects. Pareidolic response in the NPT was observed in 47.5% and 18.8% of patients with PD and MSA, respectively. The number of pareidolic responses in patients with PD was significantly larger compared with patients with MSA (P=0.001). ROC curve analyses showed the sensitivity and specificity at 33% and 98%, respectively. Among patients with PD, those with pareidolias demonstrated higher State-Trait Anxiety Inventory-state (P=0.044) and State-Trait Anxiety Inventory-trait (P=0.044) than those without pareidolias. Pareidolias can be found in patients with PD without visual hallucinations, and the pareidolia test may be a highly specific test for differentiating PD from MSA. Thus, anxiety may be associated with pareidolias in patients with PD.

Coexistence of neuronal intranuclear inclusion disease and amyotrophic lateral sclerosis: an autopsy case.

BACKGROUND: Neuronal intranuclear inclusion disease (NIID) is a rare neurodegenerative disease. Pathologically, it is characterized by eosinophilic hyaline intranuclear inclusions in the cells of the visceral organs as well as central, peripheral, and autonomic nervous system cells. Recently, a GGC repeat expansion in the NOTCH2NLC gene has been identified as the etiopathological agent of NIID. Interestingly, this GGC repeat expansion was also reported in some patients with a clinical diagnosis of amyotrophic lateral sclerosis (ALS). However, there are no autopsy-confirmed cases of concurrent NIID and ALS. CASE PRESENTATION: A 60-year-old Taiwanese woman reported a four-month history of progressive weakness beginning in the right foot that spread to all four extremities. She was diagnosed with ALS because she met the revised El Escorial diagnostic criteria for definite ALS with upper and lower motor neuron involvement in the cervical, thoracic, and lumbosacral regions. She died of respiratory failure at 22 months from ALS onset, at the age of 62 years. Brain magnetic resonance imaging (MRI) revealed lesions in the medial part of the cerebellar hemisphere, right beside the vermis (paravermal lesions). The subclinical neuropathy, indicated by a nerve conduction study (NCS), prompted a potential diagnosis of NIID. Antemortem skin biopsy and autopsy confirmed the coexistence of pathology consistent with both ALS and NIID. We observed neither eccentric distribution of p62-positive intranuclear inclusions in the areas with abundant large motor neurons nor cytopathological coexistence of ALS and NIID pathology in motor neurons. This finding suggested that ALS and NIID developed independently in this patient. CONCLUSIONS: We describe a case of concurrent NIID and ALS discovered during an autopsy. Abnormal brain MRI findings, including paravermal lesions, could indicate the coexistence of NIID even in patients with ALS showing characteristic clinical phenotypes.

Electrogastrography for diagnosis of early-stage Parkinson's disease.

INTRODUCTION: Patients with Parkinson's disease (PD) often present with gastric symptoms. Electrogastrography (EGG) can noninvasively assess gastric electric activity and may be useful for early PD diagnosis. The present study aimed to compare the efficacy of EGG in early PD diagnosis with those of 123I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy and odor stick identification test -Japanese version (OSIT-J). METHODS: Thirty-seven untreated PD patients (mean age ± SD, 66 ± 8years; disease duration < 3 years) and 20 healthy control subjects (68 ± 6.9 years) were recruited. EGG and OSIT-J were performed in both groups, and MIBG scintigraphy in the PD group. EGG parameters were assessed in the preprandial and early and late postprandial segments using power spectrum analysis. RESULTS: Irregular EGG waves were observed in PD patients. The preprandial instability coefficient of dominant frequency (ICDF), an index of EGG irregularity, in PD patients (9.5% [6.3%]) was higher than that in controls (3.9% [3.9%], p = 0.00005). The OSIT-J score was also lower in PD patients (4.6 [3.3]) than in controls (7.7 [3.3], p = 0.006). In receiver operating characteristics analyses, the areas under the curves of preprandial ICDF and OSIT-J were 0.83 and 0.72, respectively. The sensitivities of preprandial ICDF and MIBG (delayed-phase) scintigraphy were 73% and 70%, respectively. CONCLUSIONS: Early and untreated PD patients showed irregular EGG waves and high ICDF. EGG showed better accuracy than the olfactory test for early PD diagnosis and similar sensitivity to MIBG scintigraphy.

Clear cell injury associated with reduced expression of carbonic anhydrase II in eccrine glands consistently occurs in patients with acquired idiopathic generalized anhidrosis.

Acquired idiopathic generalized anhidrosis (AIGA) is characterized by anhidrosis/hypohidrosis without other autonomic and neurological dysfunctions. It has been believed that AIGA patients usually present no significant morphological alterations in the secretory portion of eccrine glands consisting of clear, dark and myoepithelial cells. However, we have recently revealed morphological damage of eccrine glands in AIGA patients by immunohistochemistry. Moreover, inhibitory side-effects against carbonic anhydrase II (CA II) by the antiepileptic reagent topiramate have been reported to cause heat intolerance mimicking AIGA. To determine the precise morphological changes and CA II expression in eccrine glands of AIGA patients, electron microscopic observation and immunohistochemistry were applied to skin of both anhidrotic (non-sweating) and normohidrotic (sweating-preserved) sites, taken from each patient clinically diagnosed with AIGA. We found consistent clear cell injury in eccrine glands in anhidrotic skin samples of AIGA patients. Electron micrographs demonstrated edematous, swollen and destructive damage in clear cells of eccrine glands from non-sweating areas of almost all AIGA patients. Immunohistochemically, clear cells showed reduced CA II expression that was heterogeneously distributed in non-sweating skin. Some areas showed almost complete loss of CA II expression in spite of preserved dark cells, and others showed mild or moderate loss of it. Selective destruction of clear cells resulting in heterogenous atrophy in AIGA patients may be important to elucidate its etiology.

High-Contrast In Vivo Imaging of Tau Pathologies in Alzheimer's and Non-Alzheimer's Disease Tauopathies.

A panel of radiochemicals has enabled in vivo positron emission tomography (PET) of tau pathologies in Alzheimer's disease (AD), although sensitive detection of frontotemporal lobar degeneration (FTLD) tau inclusions has been unsuccessful. Here, we generated an imaging probe, PM-PBB3, for capturing diverse tau deposits. In vitro assays demonstrated the reactivity of this compound with tau pathologies in AD and FTLD. We could also utilize PM-PBB3 for optical/PET imaging of a living murine tauopathy model. A subsequent clinical PET study revealed increased binding of 18F-PM-PBB3 in diseased patients, reflecting cortical-dominant AD and subcortical-dominant progressive supranuclear palsy (PSP) tau topologies. Notably, the in vivo reactivity of 18F-PM-PBB3 with FTLD tau inclusion was strongly supported by neuropathological examinations of brains derived from Pick's disease, PSP, and corticobasal degeneration patients who underwent PET scans. Finally, visual inspection of 18F-PM-PBB3-PET images was indicated to facilitate individually based identification of diverse clinical phenotypes of FTLD on a neuropathological basis.

Evaluation of the Tiller Switch Layout of a Tractor Using Eye-Fixation Related Potentials.

The human-machine interface (HMI) of a tractor cockpit includes not only the steering wheel and pedals, but also many levers and switches. According to a report from the National Agriculture and Food Research Organization of Japan, the HMI layout often differs from the operator's expectation. This gap between expectations and reality has led to operator errors and market complaints. However, few reports have ergonomically evaluated these arrangements. Our previous work showed that this gap can be evaluated by the amplitude of the P300 component of the event-related potentials (ERPs) for discrimination tasks by using a picture of the vehicle cockpit on the display. However, in real-world driving and operation situations, eye movements occur. In such cases, the eye-fixation related potential (EFRP) may be used. The EFRP appears at the end of a saccade, which is a rapid movement of the eyes between fixation points. Its positive component, called the lambda response, is reported to reflect the human attention level to visual targets. We hypothesize that if the HMI layout differs from the user's expectation, operation becomes difficult and the user's attention to the target during operation will be reduced. In order to confirm this hypothesis, an experiment was conducted during the actual operation of a tractor while changing the tiller switch position. The participants were 13 adult males with experience in tractor operations. The amplitude of the lambda wave was reduced when the switch position was different from the user's expectations, reflecting the decrease in attention caused by the increased difficulty of operating the tiller. We suggest that the amplitude of the lambda response can be used as the evaluation index for optimizing the switch position.

Recurrent Neurological Episodes for 10 Years Preceding Skin Lesions in Neuro-Sweet Disease.

An absence of skin lesions at the neurological onset may obscure the diagnosis of neuro-Sweet disease (NSD). We herein report a 32-year-old man with NSD in whom neurological symptoms preceded the development of skin lesions by 10 years. The patient exhibited four distinct neurological episodes: meningoencephalitis, scattered brain lesions, ocular flutter, and isolated seizures. Acute relapses responded to corticosteroid therapy, and the patient was successfully maintained on corticosteroid and dapsone combination therapy. NSD should be considered in the differential diagnosis of patients with recurrent neurological manifestations, especially with both meningeal and brain parenchymal involvement, even if no skin lesions are observed.

POEMS syndrome and calciphylaxis: an unrecognized cause of abnormal small vessel calcification.

BACKGROUND: Calciphylaxis is a syndrome consisting of vascular calcification, thrombosis, and skin necrosis. The syndrome develops often in chronic hemodialysis patients. However, there have been several case reports on calciphylaxis in patients with POEMS (polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes) syndrome, a systemic disease associated with plasma cell dyscrasia and upregulation of vascular endothelial growth factor (VEGF). METHODS: In 76 POEMS patients and 86 age- and gender-matched disease controls, we studied abnormal small vessel calcification by computed tomography (CT) of the soft tissues. Clinical and laboratory profiles were compared between POEMS patients with and without calciphylaxis. Histological examination was performed in six autopsy cases. RESULTS: Small vessel calcification on CT was found in 17 % of POEMS patients and in none of the controls (P < 0.001). Autopsy confirmed calciphylaxis in 2 (33 %) patients. Among POEMS patients, higher disease activity, including more severe neuropathy and ascites, higher serum levels of interleukin-6, and lower serum albumin levels, was associated with the development of calciphylaxis. Serum levels of creatinine, calcium, and phosphate were not related to the presence of calciphylaxis. CONCLUSIONS: Calciphylaxis is often present in patients with POEMS syndrome. Upregulation of multiple inflammatory cytokines such as VEGF and interleukin-6 may contribute to the development of calciphylaxis, by entirely different mechanism from that in chronic dialysis. POEMS syndrome should be recognized as a potential cause of calciphylaxis.

Myocardial (123)I-MIBG Uptake and Cardiovascular Autonomic Function in Parkinson's Disease.

Introduction. Patients with Parkinson's disease (PD) showed reduced myocardial (123)I-MIBG uptake, which may affect autonomic regulation. We investigated correlation between MIBC accumulation and cardiovascular autonomic function in PD. Methods. We performed myocardial MIBG scintigraphy, heart rate variability (HRV) analysis, and the head-up tilt test (HUT) in 50 PD patients (66.4 ± 7.8 years; duration 5.5 ± 5.9 years). Autonomic function tests were also performed in 50 healthy controls (66.5 ± 8.9 years). As HRV parameters, a high-frequency power (HF, 0.15-0.4 Hz), a low-frequency power (LF, 0.04-0.15 Hz), and LF/HF ratio were used. Results. Our PD patients had a significant reduction in LF and HF compared with the controls (P = 0.005 and P = 0.01). In HUT, systolic and diastolic blood pressure falls in the PD group were significantly greater than those in the controls (P = 0.02 and P = 0.02). The washout rate of MIBG was negatively correlated with blood pressure changes during HUT. Conclusion. Our PD patients showed reduced HRV, blood pressure dysregulation, and reduced MIBG accumulation, which was correlated with blood pressure dysregulation. Orthostatic hypotension in PD may be mainly caused by sympathetic postganglionic degeneration.

Skin sympathetic function in complex regional pain syndrome type 1.

PURPOSE: Cutaneous sympathetic pathophysiology in complex regional pain syndrome type 1 (CRPS-1) is not yet completely understood. To evaluate cutaneous sympathetic dysfunction in CRPS-1, we evaluated sympathetic sweat response (SSwR) and skin vasomotor reflex (SkVR) in CRPS-1 patients. METHODS: We studied 10 CRPS-1 patients (age 41 ± 13 years; 5 females and 5 males; disease duration 20 ± 22 months) and 10 healthy subjects (age 44 ± 13 years; 3 females and 7 males). SkVRs and SSwRs to several sympathetic activating procedures were recorded on the palms of the CRPS-1 patients (affected side) and controls (right side). RESULTS: There were no significant differences in the baselines of sweat output and skin blood flow between the CRPS-1 and control groups. SSwR and SkVR amplitudes were significantly lower in the CRPS-1 group than in the control group. There was no significant correlation between disease duration and SSwR or SkVR amplitudes among the patients. CONCLUSIONS: The reduced SSwRs and SkVRs in the affected limb of our CRPS-1 patients may reflect underlying damage to the sympathetic postganglionic fibres.