Multiple system atrophy: a review of 203 pathologically proven cases

A 'single toxin-double lesion' rat model of striatonigral degeneration by intrastriatal 1-methyl-4-phenylpyridinium ion injection: a motor behavioural analysis

Previous attempts to reproduce striatonigral degeneration, the core pathology underlying Parkinsonism in multiple system atrophy, have been impeded by interactions in the neurotoxins used to replicate striatal and nigral degeneration in rodents. To overcome these interactions, we have developed a new model of striatonigral degeneration which uses a single unilateral administration of 1-methyl-4-phenylpyridinium ion (MPP(+)) into the rat striatum. Spontaneous and drug-induced rotational behaviour, thigmotactic scanning, stepping adjusting steps and paw reaching deficits were compared in four groups of animals: group 1 (control), group 2 (20 microg quinolinic acid), group 3 (20 microg 6-hydroxydopamine), and group 4 (90 nmol MPP(+)). MPP(+) administration resulted in the absence of the amphetamine-induced ipsilateral bias observed in the 6-hydroxydopamine group and of the apomorphine-induced ipsilateral bias observed in the quinolinic acid group. There was no thigmotactic scanning asymmetry in the MPP(+)-injected rats compared to the quinolinic acid- and the 6-hydroxydopamine-injected rats. MPP(+) elicited a bilateral stepping adjustment deficit similar to that found in the quinolinic acid group when compared to controls. MPP(+) also elicited a more severe and significant contralateral deficit in paw reaching compared to controls, 6-hydroxydopamine and quinolinic acid groups. Histopathology revealed a significant reduction of the lesioned striatal surface (-47.53%) with neuronal loss and increased astrogliosis in the MPP(+) group grossly similar to that found in the quinolinic acid group. Contrary to the latter group, however, loss of intrastriatal and striatal-crossing fibre bundles was observed in the MPP(+) group as there was also some retrograde degeneration in the ipsilateral thalamic parafascicular nucleus. The mean loss of dopaminergic cells in the ipsilateral substantia nigra pars compacta in MPP(+) rats was less marked (-48.8%) than in the 6-hydroxydopamine rats (-63.6%) and was not significant in quinolinic acid rats (-5.2%). This study shows that a single unilateral intrastriatal administration of MPP(+) induces a unique motor behaviour resulting from both nigral and striatal degeneration, but also from possible extrastriatal damage. This 'single toxin-double lesion' paradigm may thus serve as a rat model of striatonigral degeneration.

Autonomic nervous system testing may not distinguish multiple system atrophy from Parkinson's disease

BACKGROUND

Formal laboratory testing of autonomic function is reported to distinguish between patients with Parkinson's disease and those with multiple system atrophy (MSA), but such studies segregate patients according to clinical criteria that select those with autonomic dysfunction for the MSA category.

OBJECTIVE

To characterise the profiles of autonomic disturbances in patients in whom the diagnosis of Parkinson's disease or MSA used criteria other than autonomic dysfunction.

METHODS

47 patients with parkinsonism and autonomic symptoms who had undergone autonomic laboratory testing were identified and their case records reviewed for non-autonomic features. They were classified clinically into three diagnostic groups: Parkinson's disease (19), MSA (14), and uncertain (14). The performance of the patients with Parkinson's disease was compared with that of the MSA patients on five autonomic tests: RR variation on deep breathing, heart rate changes with the Valsalva manoeuvre, tilt table testing, the sudomotor axon reflex test, and thermoregulatory sweat testing.

RESULTS

None of the tests distinguished one group from the other with any statistical significance, alone or in combination. Parkinson's disease and MSA patients showed similar patterns of autonomic dysfunction on formal testing of cardiac sympathetic and parasympathetic, vasomotor, and central and peripheral sudomotor functions.

CONCLUSIONS

This study supports the clinical observation that Parkinson's disease is often indistinguishable from MSA when it involves the autonomic nervous system. The clinical combination of parkinsonism and dysautonomia is as likely to be caused by Parkinson's disease as by MSA. Current clinical criteria for Parkinson's disease and MSA that direct patients with dysautonomia into the MSA group may be inappropriate.

Diagnosing multiple system atrophy with greater accuracy: combined analysis of the clonidine-growth hormone test and external anal sphincter electromyography

The clonidine-growth hormone test (CGHT) has been proposed as a means of differentiating multiple system atrophy (MSA) from idiopathic Parkinson's disease (PD). However, it is controversial whether the CGHT is valid. We sought to confirm the validity of the CGHT and to compare the diagnostic accuracy of the CGHT with that of external anal sphincter electromyelography (Sph-EMG) for MSA. We performed the CGHT and the Sph-EMG on 21 PD patients, 23 patients with probable MSA of parkinsonian type (MSA-p), and 22 patients with probable MSA of cerebellar type (MSA-c). We compared the sensitivity, specificity, and positive and negative predictive values (PPV and NPV) of CGHT, Sph-EMG, and a combination of the two tests. We also evaluated the correlations of Unified Parkinson's Disease Rating Scale (UPDRS) scores with the results of the two tests. There was no significant difference between the UPDRS scores for the PD and MSA-p groups. Serum growth hormone concentrations after clonidine significantly increased in PD (mean increase +/- SEM, 4.19 +/- 0.92 ng/ml; P < 0.0001), but remained unchanged in both MSA-p (0.83 +/- 0.61 ng/ml) and MSA-c (1.45 +/- 0.58 ng/ml). The growth hormone responses to clonidine in MSA-p were significantly different from those in PD (P < 0.05). Abnormal, denervated Sph-EMG was observed in 95.7% of MSA-p, 86.4% of MSA-c, and 33.3% of PD patients. Compared to Sph-EMG, the CGHT was less sensitive but more specific in both MSA-p and MSA-c. The result of neither test correlated with the severity of parkinsonism. Interestingly, combining the results of the CGHT and Sph-EMG markedly increased the specificity (85.7% in the CGHT and 66.7% in Sph-EMG vs. 95.2% in the combination study) and the PPV in both MSA-p (85.7% and 75.9% vs. 94.4%) and MSA-c (82.4% and 73.1% vs. 91.7%). We confirm that the CGHT can distinguish MSA-p from PD. Its sensitivity is lower and its specificity higher than Sph-EMG. Compared to either test alone, combined testing with the CGHT and Sph-EMG increased specificity and PPV, thereby enhancing accuracy in the diagnosis of MSA.

Differentiating multiple system atrophy from Parkinson's disease: contribution of striatal and midbrain MRI volumetry and multi-tracer PET imaging

OBJECTIVES

The differential diagnosis between typical idiopathic Parkinson's disease (PD) and the striatonigral variant of multiple system atrophy (MSA-P) is often difficult because of the presence of signs and symptoms common to both forms of parkinsonism, particularly at symptom onset. This study investigated striatal and midbrain findings in MSA-P and PD patients in comparison with normal controls with the use of positron emission tomography (PET) and three dimensional magnetic resonance imaging (3D MRI) based volumetry to increase the differential diagnostic accuracy between both disease entities.

METHODS

Nine patients with MSA-P, 24 patients with PD, and seven healthy controls were studied by MRI and PET with 6-[(18)F]-fluoro-L-dopa (FDOPA), [(18)F]fluoro-deoxyglucose (FDG), and 11-C-Raclopride (RACLO). Striatal and extrastriatal volumes of interest (VOI) were calculated on the basis of the individual MRI data. The PET data were transferred to the VOI datasets and subsequently analysed.

RESULTS

MSA-P differed significantly from PD patients in terms of decreased putaminal volume, glucose metabolism, and postsynaptic D2 receptor density. The striatal FDOPA uptake was equally impaired in both conditions. Neither MRI volumetry nor PET imaging of the midbrain region further contributed to the differential diagnosis between PD and MSA-P.

CONCLUSIONS

The extent and spatial distribution of functional and morphological changes in the striatum permit the differentiation of MSA-P from PD. Both, multi-tracer PET and 3D MRI based volumetry, may be considered equivalent in the assessment of different striatal abnormality in both disease entities. In contrast, MRI and PET imaging of the midbrain does not provide a further gain in diagnostic accuracy.

Application of the International Cooperative Ataxia Scale rating in multiple system atrophy

We assessed the International Cooperative Ataxia Scale (ICARS) as a means of extracting and rating cerebellar signs in multiple system atrophy (MSA). Cross-sectional analysis of internal consistency, factor structure, and correlation with parkinsonism severity (Unified Parkinson's Disease Rating Scale [UPDRS] III) of the ICARS, in 50 unselected MSA patients (mean age, 67.6 years; mean disease duration, 5.5 years), 50 age-matched and disease duration-matched Parkinson' disease (PD) patients, and 50 control subjects. Fifteen patients (30%) had MSA-C (cerebellar subtype) and 35 (70%) MSA-P (parkinsonism subtype), and 66% had at least one cerebellar sign. The total ICARS score was much higher (fivefold) in MSA compared to PD patients. The ICARS score was twofold higher in MSA-C than in MSA-P patients. MSA-C patients had a higher score than MSA-P mainly on posture and gait disturbances and kinetic functions subscores. All the ICARS items were significantly more severe in MSA than in PD patients, who in turn scored higher than the controls. In MSA, internal consistency was excellent (Cronbach = 0.93). Factor structure analysis revealed four clinically distinct subscores, in accordance with the scale structure, which accounted for 70% of the variance. The ICARS showed less consistency and accuracy in PD patients; however, the ICARS scores significantly correlated with the UPDRS-III scores in both MSA and PD patients. The ICARS appears a useful tool to extract and rate the severity of cerebellar signs in MSA; however, it is clearly contaminated by parkinsonian features.

Clinical correlates of the pathology underlying parkinsonism: a population perspective

We correlated the clinical features with pathological findings in an autopsy series of cases of incident parkinsonism. We used the medical records-linkage system of the Rochester Epidemiology Project to identify all incident cases of parkinsonism in Olmsted County, MN, for the years 1976 to 1990. Medical histories were abstracted in a standardized manner. Included in this study were those incident cases who died and underwent autopsy. Brain sections were studied with routine histology and special stainings. A neuropathologist blinded to any clinical information assigned cases to neuropathological categories. We found 364 incident cases of parkinsonism of which 235 were deceased at the time of this study; there were 39 autopsied brains available for analysis (17% of deceased cases). Of the 16 patients diagnosed pathologically with Lewy body disease, documentation indicated that 8 had an early dementia, 3 had prominent dysautonomia, and 2 had prominent ataxia. Of the 7 patients diagnosed pathologically with progressive supranuclear palsy, 4 had no documentation of supranuclear gaze palsy, and 3 had no documentation of early falls. Of the 3 patients diagnosed pathologically with multiple system atrophy, none had prominent ataxia or dysautonomia documented. Of the 5 patients with vascular disease at pathology, none had been given the clinical diagnosis of vascular parkinsonism. Of the 8 cases given the clinical diagnosis of drug-induced parkinsonism, 6 were found to have basal ganglia pathology. The autopsied cases in this study were not representative of all patients with parkinsonism, because atypical cases are more likely to come to autopsy than typical ones. Despite this selection bias, the retrospective data collection, and the small sample size, we made several observations that illustrate the difficulty in achieving an accurate antemortem diagnosis of parkinsonism.

The nature of the autonomic dysfunction in multiple system atrophy

The concept that multiple system atrophy (MSA, Shy-Drager syndrome) is a disorder of the autonomic nervous system is several decades old. While there has been renewed interest in the movement disorder associated with MSA, two recent consensus statements confirm the centrality of the autonomic disorder to the diagnosis. Here, we reexamine the autonomic pathophysiology in MSA. Whereas MSA is often thought of as "autonomic failure", new evidence indicates substantial persistence of functioning sympathetic and parasympathetic nerves even in clinically advanced disease. These findings help explain some of the previously poorly understood features of MSA. Recognition that MSA entails persistent, constitutive autonomic tone requires a significant revision of our concepts of its diagnosis and therapy. We will review recent evidence bearing on autonomic tone in MSA and discuss their therapeutic implications, particularly in terms of the possible development of a bionic baroreflex for better control of blood pressure.

Cerebral metabolic changes in early multiple system atrophy: a PET study

Previous positron emission tomography (PET) studies have shown widespread hypometabolism in the brain of advanced MSA but the time course of these metabolic abnormalities is largely unknown. In order to clarify the principal disease processes in multiple system atrophy (MSA) in the early stage, we investigated regional cerebral glucose metabolism (rCMGglc) and nigral dopaminergic function in nine patients with early stage of MSA using [(18)F]fluorodeoxyglucose (FDG) and 6-L-[(18)F]fluorodopa ((18)F-Dopa) positron emission tomography (PET) (two men and seven women; age, 59.3+/-5.4 years; disease duration, 29.7+/-14.6 months). The rCMRglc in the early MSA patients significantly decreased in the cerebellum, brainstem, and striatum compared with that in nine normal subjects. A significant correlation was found between the severity of autonomic dysfunction and rCMRglc within the brainstem. The severity of extrapyramidal signs also correlated with the decline of F-Dopa uptake but not that of rCMRglc within the striatum. The degree of atrophy on MRI has correlated with neither the clinical symptoms nor rCMRglc at the cerebellum and the brainstem. Our PET studies demonstrated widespread metabolic abnormalities except for the cerebral cortex in the brain of MSA even in the early stage. The hypometabolism in the brainstem was tightly linked to the autonomic dysfunction. Not the striatal dysfunction but the nigral damage may be responsible for the extrapyramidal symptoms in early MSA.

Genetic ataxia

Advances in molecular genetics have led to identification of an increasing number of genes responsible for inherited ataxic disorders. Consequently, DNA testing has become a powerful method to unambiguously establish the diagnosis in some of these disorders; however, there are limitations in this approach. Furthermore, the ethical, social, legal and psychological implications of the genetic test results are complex, necessitating appropriate counseling. This article intends to help the practicing neurologist clinically differentiate these disorders, choose appropriate genetic tests, and recognize the importance of counseling.

Dual SPECT of dopamine system using [99mTc]TRODAT-1 and [123I]IBZM in normal and 6-OHDA-lesioned formosan rock monkeys

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by a severe loss of the dopaminergic neurons in the substantia nigra pars compacta. In this study, we evaluated pre- and post-synaptic binding sites of the dopamine system in three normal and one parkinsonian monkeys using simultaneous [99mTc]TRODAT-1 and [123I]IBZM imaging. The parkinsonian monkey was induced by injecting 6-hydroxydopamine (6-OHDA) bilaterally into the medial forebrain bundle under MRI guidance. [99mTc]TRODAT-1 (targeting dopamine transporters) and [123I]IBZM (targeting D(2)/D(3) receptors) were administered almost simultaneously and the SPECT images were acquired over 4 h using a dual-headed gamma camera equipped with ultra-high resolution fan-beam collimators. Data were obtained using energy window of 15% centered on 140 keV for 99mTc in conjunction with 10% asymmetric energy window in a lower bound at 159 keV for 123I. Single SPECT studies of [99mTc]TRODAT-1 and [123I]IBZM were also performed. We found a comparable image quality and uptake ratios between single- and dual-isotope studies. There are higher TRODAT-1 uptakes in the control monkeys than the 6-OHDA-lesioned monkey. The uptake of [123I] IBZM showed no significant difference between controls and 6-OHDA-lesioned monkey. Our results suggest that dual isotope imaging using [99mTc]TRODAT-1 and [123I]IBZM may be a useful means in evaluating the changes of both pre- and post-synaptic dopamine system in a primate model of parkinsonism.

Presynaptic parkinsonism in multiple system atrophy mimicking Parkinson's disease: a clinicopathological case study

We describe the clinicopathological findings in a patient aged 63 years at death who, at age 55 years, developed levodopa-responsive parkinsonism with no atypical features. A diagnosis of idiopathic Parkinson's disease (PD) was made. During the clinical course, fluctuations and dyskinesias appeared. Eight years after onset, he was successfully treated with subthalamic nucleus stimulation but died 3 weeks postoperatively from pulmonary embolus. Brain autopsy showed marked neuronal loss and gliosis in the substantia nigra and locus coeruleus, and, to a much lesser extent, in the basis pontis, inferior olivary nuclei, and cerebellar cortex. Striatum was normal. There were numerous oligodendroglial and neuronal cytoplasmic inclusions and neuropil threads, the highest density being localized in the pons and cerebellar white matter. No Lewy bodies were observed. We conclude that nigral, presynaptic parkinsonism may occur in multiple system atrophy, which even in the long run can be indistinguishable from PD. Putaminal preservation accounts for good response to both levodopa therapy and subthalamic nucleus stimulation.

Parkinsonism in multiple system atrophy: natural history, severity (UPDRS-III), and disability assessment compared with Parkinson's disease

We analyzed parkinsonian features in multiple system atrophy (MSA) compared with age- and disease duration-matched Parkinson's disease (PD) patients, and assessed the applicability of the Unified Parkinson's Disease Rating Scale (UPDRS) -III motor scale as a means of rating their severity. Cross-sectional analysis of parkinsonism was done using UPDRS-III, International Cerebellar Atatia Rating Scale, and disability scales (Hoehn and Yahr [H&A], Schwab and England, Katz and Lawton) in 50 unselected MSA patients and in 50 matched PD patients. At symptom onset, falls occurred 10 times more frequently in MSA, whereas limb tremor was 10 times more common in PD. At first visit (10.2 months), hemiparkinsonism and pill-rolling rest tremor were less common in MSA. Hypomimia, atypical rest, postural or action tremor, as well as postural instability were more frequent in MSA. At study examination (62.4 months), parkinsonian signs in MSA patients were more frequently symmetrical and associated with axial rigidity, antecollis and postural instability. A levodopa response of >50% was seen in <10% of MSA patients. Modified H&Y stages (3.2 +/- 1.3 vs. 2.2 +/- 0.78) and UPDRS-III scores (48.14 +/- 19.5 vs. 31.74 +/- 12.9) were significantly (P = 0.0001) higher in MSA. The internal consistency of the UPDRS-III was fair in MSA patients (Cronbach's alpha >0.90), and correlated well with marked dependency on the Schwab and England and Katz and Lawton scales. Factor structure analysis of UPDRS-III in MSA showed five clinically distinct subscores accounting for 74% of the variance, differing from PD by the dependency of the face-speech and limb bradykinesia items and independence of the postural-action tremor from the rest tremor items. There was a significant correlation (R(2) = 0.70, P = 0.001) between ICARS ataxia and UPDRS-III scores in MSA patients. Results confirm a distinct profile of parkinsonism in MSA and greater severity and disability compared with PD. It also indicates that the UPDRS-III provides a useful severity measure of parkinsonism in MSA, albeit contaminated by additional cerebellar dysfunction.

Severe generalized dystonia due to primary putaminal degeneration: case report and review of the literature

Putaminal lesions of a variety of etiologies may cause secondary dystonia. We report on a case of primary putaminal degeneration as a cause of severe childhood-onset generalized dystonia and review the literature of the pathology of dystonia. A 44-year-old patient with severe generalized childhood-onset dystonia and macrocephaly underwent neurological evaluation and neuropathological examination. Neurological examination was normal apart from dystonia and signs referable to prior cryothalamotomy. Workup for metabolic and genetic causes of dystonia was negative. Neuroimaging showed severe bilateral putaminal degeneration, which subsequently correlated with the neuropathological findings of gliosis, spongiform degeneration, and cavitation. The substantia nigra pars compacta contained a normal number of neurons but decreased tyrosine hydroxylase immunoreactivity. There were no histopathological markers of other metabolic or degenerative diseases.

Progression and prognosis in multiple system atrophy: an analysis of 230 Japanese patients

We investigated the disease progression and survival in 230 Japanese patients with multiple system atrophy (MSA; 131 men, 99 women; 208 probable MSA, 22 definite; mean age at onset, 55.4 years). Cerebellar dysfunction (multiple system atrophy-cerebellar; MSA-C) predominated in 155 patients, and parkinsonism (multiple system atrophy-parkinsonian; MSA-P) in 75. The median time from initial symptom to combined motor and autonomic dysfunction was 2 years (range 1-10). Median intervals from onset to aid-requiring walking, confinement to a wheelchair, a bedridden state and death were 3, 5, 8 and 9 years, respectively. Patients manifesting combined motor and autonomic involvement within 3 years of onset had a significantly increased risk of not only developing advanced disease stage but also shorter survival (P < 0.01). MSA-P patients had more rapid functional deterioration than MSA-C patients (aid-requiring walking, P = 0.03; confinement to a wheelchair, P < 0.01; bedridden state, P < 0.01), but showed similar survival. Onset in older individuals showed increased risk of confinement to a wheelchair (P < 0.05), bedridden state (P = 0.03) and death (P < 0.01). Patients initially complaining of motor symptoms had accelerated risk of aid-requiring walking (P < 0.01) and confinement to a wheelchair (P < 0.01) compared with those initially complaining of autonomic symptoms, while the time until confinement to a bedridden state and survival were no worse. Gender was not associated with differences in worsening of function or survival. On MRI, a hyperintense rim at the lateral edge of the dorsolateral putamen was seen in 34.5% of cases, and a 'hot cross bun' sign in the pontine basis (PB) in 63.3%. These putaminal and pontine abnormalities became more prominent as MSA-P and MSA-C features advanced. The atrophy of the cerebellar vermis and PB showed a significant correlation particularly with the interval following the appearance of cerebellar symptoms in MSA-C (r = 0.71, P < 0.01, r = 0.76 and P < 0.01, respectively), but the relationship between atrophy and functional status was highly variable among the individuals, suggesting that other factors influenced the functional deterioration. Atrophy of the corpus callosum was seen in a subpopulation of MSA, suggesting hemispheric involvement in a subgroup of MSA patients. The present study suggested that many factors are involved in the progression of MSA but, most importantly, the interval from initial symptom to combined motor and autonomic dysfunction can predict functional deterioration and survival in MSA.

Effects of a startle on heart rate in patients with multiple system atrophy

The patient cooperation usually required for neurophysiological assessment of autonomic cardioregulatory function is difficult to obtain from patients with bradykinesia. A particularly interesting condition occurs in multiple system atrophy (MSA), which features both bradykinesia and autonomic dysfunction. Another characteristic of patients with MSA is their normal motor reaction to a startling stimulus. We used startle as a stimulus for testing autonomic cardioregulatory function in patients with MSA, thus avoiding the need for patient cooperation. In 10 healthy volunteers and 8 MSA patients, we recorded the electrocardiographic QRS complex with surface electrodes attached over the chest and delivered an acoustic startle stimulus after 8 seconds of baseline recording. We calculated the ratio between the pre-stimulus and the post-stimulus heart beat intervals (R-R ratio) by dividing the mean prestimulus R-R interval by the shortest R-R interval obtained within 10 seconds poststimulus. Healthy volunteers had a significant shortening of the R-R interval. The peak of the effect occurred after 2 to 5 seconds, with a mean R-R ratio of 1.14 (S.D. = 0.09). In contrast, R-R shortening was markedly reduced in patients, even though they had a normal motor response. The mean R-R ratio in patients was 1.03 (S.D. = 0.03), significantly lower than in healthy volunteers (P < 0.01). Our results demonstrate an abnormally reduced modulation of the heart beat frequency in patients with MSA, compatible with a dysfunction on pathways responsible for autonomic regulation. The method described here may be useful in the assessment of cardioregulatory function in poorly cooperative patients with normal startle responses.

The accuracy of diagnosis of parkinsonian syndromes in a specialist movement disorder service

We have reviewed the clinical and pathological diagnoses of 143 cases of parkinsonism seen by neurologists associated with the movement disorders service at The National Hospital for Neurology and Neurosurgery in London who came to neuropathological examination at the United Kingdom Parkinson's Disease Society Brain Research Centre, over a 10-year period between 1990 and the end of 1999. Seventy-three (47 male, 26 female) cases were diagnosed as having idiopathic Parkinson's disease (IPD) and 70 (42 male, 28 female) as having another parkinsonian syndrome. The positive predictive value of the clinical diagnosis for the whole group was 85.3%, with 122 cases correctly clinically diagnosed. The positive predictive value of the clinical diagnosis of IPD was extremely high, at 98.6% (72 out of 73), while for the other parkinsonian syndromes it was 71.4% (50 out of 70). The positive predictive values of a clinical diagnosis of multiple system atrophy (MSA) and progressive supranuclear palsy (PSP) were 85.7 (30 out of 35) and 80% (16 out of 20), respectively. The sensitivity for IPD was 91.1%, due to seven false-negative cases, with 72 of the 79 pathologically established cases being diagnosed in life. For MSA, the sensitivity was 88.2% (30 out of 34), and for PSP it was 84.2% (16 out of 19). The diagnostic accuracy for IPD, MSA and PSP was higher than most previous prospective clinicopathological series and studies using the retrospective application of clinical diagnostic criteria. The seven false-negative cases of IPD suggest a broader clinical picture of disease than previously thought acceptable. This study implies that neurologists with particular expertise in the field of movement disorders may be using a method of pattern recognition for diagnosis which goes beyond that inherent in any formal set of diagnostic criteria.

Progressive cerebral atrophy in multiple system atrophy

Nine patients with multiple system atrophy (MSA) were studied based on MRI findings of cerebral hemispheric involvement. The age at onset was 56.4+/-8.6 (mean+/-S.D.) years, duration of illness at the first MRI study 2.1+/-1.1 years, duration of illness at the last study 9.7+/-2.6 years, and the follow-up duration 7.6+/-2.3 years. Controls were 85 neurologically intact persons (60.2+/-11.1 years age). In the MRI study, measurements of the ratio of each area to the intracranial area were performed for the cerebral hemisphere, frontal, temporal and parietal-occipital lobes. A significant progression of atrophy to under the normal limit was observed in the cerebrum, frontal and temporal lobes. Besides the typical pathological lesions in MSA, five autopsied patients revealed frontal lobe atrophy with mild gliosis, mild demyelination and glial cytoplasmic inclusions (GCIs). One of these patients showed remarkable frontal lobe atrophy with degenerative changes in the cerebral cortex. We observed the involvement of the cerebral hemisphere, especially the frontal lobe.

Diagnosis and treatment of supine hypertension in autonomic failure patients with orthostatic hypotension

Orthostatic hypotension is seen in various medical conditions. It can be secondary to medications or volume depletion. It can also be due to autonomic neuropathy secondary to other diseases, such as diabetes mellitus, or to primary degenerative processes of the autonomic nervous system. Orthostatic hypotension dominates the clinical picture of patients suffering from autonomic failure. Paradoxically, about one half of these patients also suffer from supine hypertension, which induces pressure natriuresis, worsening orthostatic hypotension. It also complicates the treatment of orthostatic hypotension. Supine hypertension is mediated by an increase in peripheral vascular resistance. This is due to residual sympathetic tone in patients with multiple system atrophy (Shy-Drager syndrome), but the cause is not known in patients with pure autonomic failure, who have increased vascular resistance despite very low levels or plasma norepinephrine and renin activity. The recent observation that patients with supine hypertension develop left ventricular hypertrophy suggests they should be treated. During the day, avoiding the supine position is often all that is required. Short-acting vasodilators (e.g., transdermal nitroglycerin) can be used during the night.

Dystonia in multiple system atrophy

OBJECTIVE

To delineate the frequency and nature of dystonia in multiple system atrophy (MSA).

METHODS

A cohort of 24 patients with clinically probable MSA over the past 10 years were prospectively followed up. Motor features were either dominated by parkinsonism (MSA-P subtype, n=18) or cerebellar ataxia (MSA-C, n=6). Classification of dystonic features and their changes with time was based on clinical observation during 6-12 monthly follow up visits. Parkinsonian features and complications of drug therapy were assessed. Most patients (22/24) died during the observation period. Neuropathological examination was confirmatory in all of the five necropsied patients.

RESULTS

At first neurological visit dystonia was present in 11 (46%) patients all of whom had been levodopa naive at this time point. Six patients (25%) exhibited cervical dystonia (antecollis) (MSA-P n=4, MSA-C n=2), five patients (21%) showed unilateral limb dystonia (MSA-P n=4; MSA-C n=1). A definite initial response to levodopa treatment was seen in 15/18 patients with MSA-P, but in none of the six patients with MSA-C. A subgroup of 12 patients with MSA-P developed levodopa induced dyskinesias 2.3 years (range 0.5-4) after initiation of levodopa therapy. Most patients had peak dose craniocervical dystonia; however, some patients experienced limb or generalised dystonia. Isolated peak dose limb chorea occurred in only one patient.

CONCLUSION

The prospective clinical study suggests that dystonia is common in untreated MSA-P. This finding may reflect younger age at disease onset and putaminal pathology in MSA-P. Levodopa induced dyskinesias were almost exclusively dystonic affecting predominantly craniocervical musculature. Future studies are required to elucidate the underlying pathophysiology of dystonia in MSA.

Positional down beating nystagmus in 50 patients: cerebellar disorders and possible anterior semicircular canalithiasis

OBJECTIVES

To clarify the clinical significance of positional down beat nystagmus (pDBN).

METHODS

A discussion of the neuro-otological findings in 50 consecutive patients with pDBN.

RESULTS

In 38 patients there was evidence of CNS disease (central group) but in 12 there was not (idiopathic group). In the CNS group, presenting symptoms were gait, speech, and autonomic dysfunction whereas in the idiopathic group patients mostly reported positional vertigo. The main neurological and oculomotor signs in the CNS group were explained by cerebellar dysfunction, including 13 patients with multiple system atrophy. In patients with multiple system atrophy with a prominent extrapyramidal component, the presence of pDBN was helpful in the differential diagnosis of atypical parkinsonism. No patient with pDBN had the Arnold-Chiari malformation, a common cause of constant down beat nystagmus (DBN). In the idiopathic group, the pDBN had characteristics which suggested a peripheral labyrinthine disorder: vertigo, adaptation, and habituation. In six patients an additional torsional component was found (concurrently with the pDBN in three). Features unusual for peripheral disorder were: bilateral positive Dix-Hallpike manoeuvre in nine of 12 patients and selective provocation by the straight head-hanging manoeuvre in two.

CONCLUSION

It is argued that some patients with idiopathic pDBN have benign paroxysmal positional vertigo (BPPV) with lithiasis of the anterior canal. The torsional component may be weak, because of the predominantly sagittal orientation of the anterior canal, and may not be readily seen clinically. Nystagmus provocation by bilateral Dix-Hallpike and straight head-hanging may be explained by the vertical upwards orientation of the ampullary segment of the anterior canal in the normal upright head position. Such orientation makes right-left specificity with the Dix-Hallpike manoeuvre less important than for posterior canal BPPV. This orientation requires a further downwards movement of the head, often achieved with the straight head-hanging position, to provoke migration of the canaliths. The straight head-hanging manoeuvre should be carried out in all patients with a history of positional vertigo and a negative Dix-Hallpike manoeuvre.

Combination of dopamine transporter and D2 receptor SPECT in the diagnostic evaluation of PD, MSA, and PSP

It is often difficult to differentiate clinically between Parkinson's disease (PD), multiple system atrophy (MSA), and progressive supranuclear palsy (PSP). The objective of this work was to investigate whether combined pre- and postsynaptic dopaminergic single photon emission computed tomography (SPECT) scanning can reliably demonstrate changes in the nigrostriatal dopaminergic system and help differentiate between normal controls, PD, MSA, and PSP patients. We performed SPECT evaluation of the dopamine transporter (DAT) and dopamine D2 receptors (D2). SPECT scans using [123I]beta-CIT (for DAT) and [123I]IBF (for D2) were performed in 18 patients with PD (12 dopa-naïve and 6 on levodopa and/or dopamine agonists), 7 with MSA of the striatonigral degeneration type, 6 with PSP, and 29 normal controls. Antiparkinsonian drugs were withheld for at least 12 hours before the scans. DAT and D2 binding potentials (Rv = V3/V2) were measured for caudate, anterior, and posterior putamen on the sides ipsilateral and contralateral to the worst motor symptoms. DAT binding in the posterior putamen was markedly reduced in all patients. However, D2 binding in posterior putamen was significantly increased in dopa-untreated PD, being greater than the normal range in 4 of 12 (33%), and it was significantly reduced in MSA, being below the normal range in 5 of 7 (71%). None of the patients with PD showed reduced D2 binding below the normal range in posterior putamen. The degree of DAT binding could not discriminate between the patient groups. The ratio of posterior putamen to caudate percentage D2 Rv compared with the controls showed an opposite pattern between PD or PSP and MSA; the caudate was greater in 16 of 18 with PD and 6 of 6 with PSP, whereas caudate was less in 5 of 7 with MSA. These findings suggest that DAT SPECT may be useful in differentiating parkinsonism from controls and D2 SPECT in further differentiating MSA from Parkinson's disease and possibly PSP.

New findings on the neuropathology of multiple system atrophy

Multiple system atrophy (MSA) provides a typical example of the integrative role of the central autonomic network in controlling cardiovascular, respiratory, bladder and gastrointestinal functions. There is increasing evidence that neurochemically defined neuronal groups of the brainstem are selectively affected in MSA to a much greater degree than in Parkinson's disease. These include the catecholaminergic neurons of the rostral ventrolateral medulla (C1 group) which project to the intermediolateral cell column and are involved in modulation of sympathetic vasomotor outflow, and noradrenergic neurons of the caudal ventrolateral medulla (A1 group) projecting to the magnocellular nuclei of the hypothalamus and regulating vasopressin (AVP) release. Loss of these groups of neurons may, at least in part, explain the development of orthostatic hypotension, baroreflex dysfunction, and impaired reflex AVP release in response to hypotension. There is preliminary evidence that cardiovagal neurons of the ventrolateral portion of the nucleus ambiguus, distinct from the branchimotor neurons of the compact region, may also be affected in MSA. Loss of cholinergic neurons in the medullary arcuate nucleus, considered by some to be the homologous to the central chemosensitive region of the ventral medullary surface, may contribute to disturbances in automatic ventilation, particularly during sleep, in patients with MSA.

Pathological glial tau accumulations in neurodegenerative disease: review and case report

Abnormal deposits of tau protein accumulate in glia in many neurodegenerative diseases. This suggests that in some instances the disease process may target glial tau, with neuronal degeneration a secondary consequence of this process. In this report, we summarize the pattern of glial tau pathology in various neurodegenerative disorders and add original findings from a case of sporadic frontotemporal dementia that exhibits astrocytic tau pathology. The neurodegenerative diseases span the spectrum of relative neuronal and glial tau involvement, from disorders affecting only neuronal tau to those in which abnormal tau deposits are found only in glia. From this, we conclude that glial tau can be a primary target of the disease process, and that this can lead to neuronal degeneration.

Dystonia and parkinsonism

Parkinsonism and dystonia may coexist in a number of neurodegenerative, genetic, toxic, and metabolic disorders and as a result of structural lesions in the basal ganglia. Parkinson's disease (PD) and the 'Parkinson-plus' syndromes (PPS) account for the majority of patients with the parkinsonism-dystonia combination. Dystonia, particularly when it involves the foot, may be the presenting sign of PD or PPS and these disorders should be suspected when adults present with isolated foot dystonia. Young age, female gender, and long disease duration are risk factors for PD-related dystonia, but dystonia in patients with PD is usually related to levodopa therapy. The mechanism of dystonia in PD is not well understood and the management is often challenging because levodopa and other dopaminergic agents may either improve or worsen dystonia. Other therapeutic strategies include oral medications (baclofen, anticholinergics and benzodiazepines), local injections of botulinum toxin, intrathecal baclofen, and surgical lesions or high frequency stimulation of the thalamus, globus pallidus, or subthalamus.

CSF-neurofilament and levodopa tests combined with discriminant analysis may contribute to the differential diagnosis of Parkinsonian syndromes

The differentiation between Parkinson's disease (PD), progressive supranuclear palsy (PSP) and multiple system atrophy (MSA) is important for prognostic and therapeutic purposes. In order to evaluate the diagnostic capability of two tests reflecting these items, patients fulfilling strict clinical criteria for PD (n=35), MSA (n=36) and PSP (n=14), were consecutively included. An analysis of neurofilament protein (NFL), a marker of axonal degeneration in the cerebrospinal fluid (CSF) and a levodopa test, recorded with optoelectronic technique were performed. Using discriminant analyses, the test's abilities to predict the clinical PD or non-PD (MSA and PSP) diagnoses were compared. Whereas the CSF-NFL and levodopa tests predicted 79 and 85% correct diagnoses respectively, the combined test predicted 90% correct diagnoses. We conclude that the CSF-NFL and levodopa tests provide detailed information of clinical variables on which the clinical diagnostic criteria are based. As they are pathologically unrelated, the diagnostic precision increases compared to clinical diagnoses when they are combined.

Lumping and splitting the Parkinson Plus syndromes: dementia with Lewy bodies, multiple system atrophy, progressive supranuclear palsy, and cortical-basal ganglionic degeneration

The atypical parkinsonian or Parkinson Plus syndromes are often difficult to differentiate from Parkinson's disease and each other. In this article, the clinicopathological characteristics of dementia with Lewy bodies, multiple system atrophy, progressive supranuclear palsy, and cortical-basal ganglionic degeneration are discussed. These disorders, although clinically distinct, may have more similarities than previously thought, based on modern immunocytochemical techniques and new genetic findings. These intriguing interconnections at a basic molecular level have provided the scientific rationale for lumping these diseases into two groups, the synucleinopathies and the tauopathies.

Sphincter EMG and differential diagnosis of multiple system atrophy

Multiple system atrophy (MSA) is a degenerative disease manifesting a combination of parkinsonism, cerebellar, pyramidal, and autonomic (including urinary, sexual, and anorectal) dysfunction. It is pathomorphologically defined, but lacks a definitive clinical diagnostic test. Sphincter electromyography (EMG), reflecting Onuf's nucleus degeneration, has been proposed as a helpful test; its value has been reevaluated by a critical review of the literature. In patients with probable MSA, abnormal sphincter EMG, as compared to control subjects, has been found in the majority of patients in all the different forms of the disease in most studies, including patients who, as yet, have no urological or anorectal problems. The prevalence of abnormalities in the early stages of MSA is as yet unclear. Patients with Parkinson's disease (PD) as a rule do not show severe sphincter EMG abnormalities in the early stage of the disease. Anal sphincter EMG abnormalities (abnormal spontaneous activity or motor unit potential changes three standard deviations above valid control data) distinguish MSA from PD in the first 5 years after the onset of symptoms and signs, and from pure autonomic failure, as well as from cerebellar ataxias, if other causes for sphincter denervation have been ruled out. With such criteria, the sensitivity of the method is, however, low. EMG does not distinguish MSA from progressive supranuclear palsy. Future studies should use standardized anal sphincter EMG to better compare results from different centers and precisely define the sensitivity and specificity of the method.

New trends in the treatment of orthostatic hypotension

Nonpharmacologic and pharmacologic treatment can significantly attenuate the symptoms of orthostatic hypotension. Some of the interventions that are used to treat orthostatic hypotension have been known for decades. However, several new treatment strategies have been developed in recent years. New knowledge about the pathophysiology of orthostatic syndromes has been gathered that will strongly influence the way treatments are tailored to individual patients. For example, patients with and without residual autonomic function exhibit differential responses to certain treatments. A large subgroup of patients with severe autonomic failure show a profound pressor response to water drinking. This simple effect can be exploited to treat orthostatic and postprandial hypotension in some patients. New bioengineering technologies that attempt to replicate normal baroreflex mechanisms may become available for selected patients with central autonomic dysfunction.

Familial mydriasis, cardiac arrhythmia, respiratory failure, muscular weakness and hypohidrosis

OBJECTIVES

To describe a family with some sort of progressive autonomic failure in one generation (2 affected of a sibship of 7 sisters). The main features were: mydriasis, cardiac arrhythmia, cardiomegaly, hypohidrosis, respiratory failure, and muscular weakness.

METHODS

Pupillometry, evaporimetry, and isokinetic power measurements were carried out.

RESULTS

The autonomic dysfunction pattern (mainly cardiac abnormalities, mydriasis) seems to differ somewhat from that of progressive autonomic failure (Shy-Drager syndrome). "Lewy body-like" inclusions were present, in particular in substantia nigra, but also in locus ceruleus and raphe nuclei (cell loss only in locus ceruleus). There were no oligodendroglial, cytoplasmatic inclusions, apparently a marker in multiple system atrophy. Proper Lewy bodies were also present. Differences seemed to prevail vs the Shy-Drager syndrome. Various traits: muscular weakness pattern (e.g. preferential peroneal distribution), minor elbow contractures, and arrhythmia were reminiscent of Emery-Dreifuss muscle dystrophy (E-D). Distinguishing features included: hereditary pattern, mydriasis, and hypohidrosis.

CONCLUSION

Conceivably, this disorder is close to, but still not identical with E-D.

Erythropoietin deficiency and anaemia in multiple system atrophy

Serum erythropoietin (EPO) levels are partially controlled by the sympathetic outflow to the kidney. We have studied whether patients with multiple system atrophy (MSA), known to be associated with dysautonomia, are EPO-deficient. Eighteen MSA patients were studied along with 32 idiopathic Parkinson's disease (PD) patients, 23 controls with iron-deficiency anaemia, and 18 healthy individuals. Serum creatinine was normal in all groups. Mean haemoglobin (Hb) concentration in MSA patients was 13.7 +/- 1.7 g/dL. Four MSA patients had unexplained anaemia (minimum Hb: 10.5 g/dL) and abnormal autonomic function tests including significant postural hypotension, whereas none of the PD patients was anaemic. Serum EPO levels were suppressed in relation to anaemia in MSA patients compared to elevated EPO levels in iron-deficiency anaemia patients (difference of regression lines P < 0.001), indicating EPO deficiency in the anaemic MSA patients. Serum EPO levels in PD patients were within normal range. A subset of MSA patients has anaemia and postural hypotension, which may be associated with EPO deficiency. This may have therapeutic implications.

Cardiovascular reflex testing contributes to clinical evaluation and differential diagnosis of Parkinsonian syndromes

The differentiation between Parkinson's disease (PD), progressive supranuclear palsy (PSP), and multiple system atrophy (MSA) may be difficult but is important for prognostic and therapeutic purposes. Varying degrees of autonomic failure have been described in PD and MSA, whereas its involvement in PSP remains controversial. The aim of this study was to investigate autonomic function in patients fulfilling strict clinical diagnostic criteria for the disorders above, to evaluate the diagnostic capacity of laboratory autonomic tests. The study group was consecutively recruited among patients referred to a movement disorder unit. Thirty-four patients with PD, 15 patients with PSP, and 47 patients with MSA were compared with 18 healthy age-matched controls. Autonomic tests included analysis of heart rate variability (HRV) in temporal domain, at rest and during forced respiration, as well as blood pressure (BP) changes during 75 degrees head-up tilt. HRV did not differ between groups during quiet breathing but was significantly reduced during forced respiration in MSA (P < 0.01), while PD and PSP groups did not differ from controls. Hypotensive responses during orthostatic provocation were seen in PD (P < 0.01) and MSA (P < 0.001), whereas BP remained stable in most PSP patients, not differing from the healthy control group. On an individual basis, decreased HRV and severe hypotensive responses were seen in MSA patients regardless of age and disease duration, whereas PD patients showed this combination only at high age and long duration. In PSP, only a few cases with decreased HRV and limited hypotensive responses were found. We conclude that cardiovascular reflex tests can supplement the clinical differentiation of Parkinsonian syndromes.

Simultaneous intrastriatal 6-hydroxydopamine and quinolinic acid injection: a model of early-stage striatonigral degeneration

Animal models reproducing early stages of striatonigral degeneration (SND), the core pathology underlying parkinsonism in multiple system atrophy, are lacking. We have developed a new model of early-stage SND by using a simultaneous unilateral administration of quinolinic acid (QA) and 6-hydroxydopamine (6-OHDA) into the putaminal equivalent of the rat striatum. Spontaneous and drug-induced behavior, thigmotactic scanning, paw reaching deficits, and histopathology were studied in rat groups: group 1 (control), group 2 (QA), group 3 (6-OHDA), and group 4 (QA + 6-OHDA). The double toxin administration resulted in reduction of the spontaneous and the amphetamine-induced ipsiversive bias in the 6-OHDA group and in a reduction of the apomorphine-induced ipsiversive rotations in the QA group. Simultaneous QA and 6-OHDA also reduced the thigmotactic bias observed in the 6-OHDA rats. Combined toxin elicited a nonsignificant contralateral deficit in paw reaching but a significant deficit on the ipsilateral side. Histopathology revealed a significant reduction of the lesioned striatal surface (-27%) with neuronal loss and increased astrogliosis in group 4 compared to group 2, consistent with an exacerbation of QA toxicity by additional 6-OHDA. By contrast, the mean loss of the TH-positive neurons in the ipsilateral substantia nigra pars compacta (SNc) of group 4 was less marked (-15%) than in the 6-OHDA group (-36%), indicating a possible protective action of intrastriatal QA upon 6-OHDA retrograde SNc degeneration. This study shows that a combined unilateral intrastriatal administration of QA and 6-OHDA may serve as a model of early stage SND which is more suitable for early therapeutic interventions.

The value of external anal sphincter electromyography for the diagnosis of multiple system atrophy

OBJECTIVE

To assess the value of external anal sphincter electromyography (ASEMG) for the diagnosis of multiple system atrophy (MSA) among various causes of parkinsonism. ASEMG denervation profiles have previously been proposed as a diagnosis test for MSA, but their specificity is disputed.

METHODS

ASEMG variables of 52 parkinsonian patients were analyzed according to the clinical diagnosis: MSA (n = 31) or no MSA (n = 21). Mean motor unit potential duration, percentage of polyphasicity, and the electromyographer's interpretation were analyzed according to clinical diagnosis, disease duration, genitourinary symptoms, gender, parity, and history of pelvic surgery.

RESULTS

All patients with MSA showed ASEMG denervation. Mean motor unit potential duration was the most discriminant variable. No patient with MSA had a mean duration less than 12 ms and no patient without MSA had one greater than 16 ms. ASEMG discriminates between patients with MSA and Parkinson's disease. Using a threshold of 13 ms, the sensitivity was 80% and specificity was almost 70% (positive predictive value, 80%) for the diagnosis of MSA. Age, history of pelvic surgery, and to a lesser extent, female gender, parity, disease duration, and presence of urinary symptoms increased the likelihood of abnormal ASEMG.

CONCLUSION

ASEMG was highly sensitive and rather specific for the diagnosis of MSA.

Complex motor disturbances in a sequential double lesion rat model of striatonigral degeneration (multiple system atrophy)

This study characterizes paw reaching, stepping and balance abnormalities in a double lesion rat model of striatonigral degeneration, the core pathology underlying levodopa unresponsive parkinsonism associated with multiple system atrophy. Extensive unilateral nigral or striatal lesions induced by 6-hydroxydopamine or quinolinic acid, respectively, produced a similarly marked contralateral paw reaching deficit without further deterioration following a secondary (complementary) lesion of ipsilateral striatum or substantia nigra. Contralateral stepping rates were reduced by unilateral 6-hydroxydopamine lesions without further deterioration following the secondary striatal lesion. In contrast, initial unilateral striatal quinolinic acid injections induced bilateral stepping deficits that significantly worsened contralaterally following the secondary nigral lesion. Contralateral sidefalling rates were significantly increased following primary nigral and striatal lesions. Secondary nigral but not secondary striatal lesions worsened contralateral sidefalling rates. Histological studies revealed subtotal (>90%) depletion of dopaminergic neurons in substantia nigra pars compacta and variable degrees of striatal degeneration depending on the lesion sequence. Animals pre-lesioned with 6-hydroxydopamine showed significantly larger residual striatal surface areas following the secondary striatal quinolinic acid lesion compared to animals with primary striatal quinolinic acid lesions (P<0.001). These findings are in line with previous experimental studies demonstrating that striatal dopamine depletion confers neuroprotection against subsequent excitotoxic injury. Whether loss of dopaminergic neurons protects against the striatal disease process occurring in multiple system atrophy (Parkinson-type) remains to be elucidated. In summary, this is the first experimental study to investigate spontaneous motor behaviour in a unilateral double lesion rat model. Our observations are consistent with a complex interaction of nigral and striatal lesions producing distinct behavioural and histological changes depending on the lesion sequence. Tests of forelimb akinesia and complex motor behaviour appear to provide a reliable tool that will be helpful for monitoring the effects of interventional strategies such as embryonic neuronal transplantation in the rat model of striatonigral degeneration.

Lack of autonomic nervous dysfunction in progressive supranuclear palsy, a study of blood pressure variability

Blood pressure and heart rate variability were analyzed in eight patients with progressive supranuclear palsy in comparison with two control groups (10 healthy patients and 10 patients with multiple system atrophy). Blood pressure and heart rate were recorded using digital photoplethysmography with the patient in supine position and during a head-up-tilt test (70 degrees for 10 minutes). Spectral analysis was performed using fast Fourier transformation for 512 consecutive systolic blood pressure and heart rate values. The head-up-tilt test induced a significant increase in systolic blood pressure in patients with progressive supranuclear palsy and in healthy patients and a significant systolic blood pressure decrease in patients with multiple system atrophy. During the head-up-tilt test, low-frequency energy of systolic blood pressure (70-130 mHz) that reflected baroreflex-dependent sympathetic tone also increased in patients with progressive supranuclear palsy and in healthy patients. By contrast, in patients with multiple system atrophy, the low-frequency energy of systolic blood pressure decreased significantly. The changes observed in the low-frequency band and the high-frequency band of heart rate (reflecting parasympathetic drive to the heart) were not different among the three groups. These data show the lack of impairment in autonomic nervous system activity in patients with progressive supranuclear palsy.

Nonparkinsonian tremors

Tremors other than those associated with Parkinson's disease are commonly encountered in clinical practice. The differentiation of tremor subtypes depends primarily on the presence of distinct clinical characteristics and is facilitated by the use of consistent nomenclature. Such differentiation can be helpful in determining the etiology of the tremor and assist in its management. In this review, the authors outline recently proposed changes to classification and review the clinical features, differential diagnosis, and current therapy for nonparkinsonian tremors.

The pathogenesis of multiple system atrophy: past, present, and future

Multiple system atrophy is a sporadic, adult-onset neurodegenerative disease of unknown etiology. The condition may be unique among neurodegenerative diseases by the prominent, if not primary, role played by the oligodendroglial cell in the pathogenetic process. Recent developments in our understanding of multiple system atrophy have included the detection of glial cytoplasmic inclusions and alpha-synuclein accumulation in these inclusions. The latter finding links multiple system atrophy as an "alpha-synucleinopathy" to Parkinson's disease and dementia with Lewy bodies. This article reviews recent important findings of potential relevance to the pathogenesis of multiple system atrophy. We also speculate on areas in which further advances may be made to progress our understanding of this devastating condition.

Stridor and death in multiple system atrophy

Patients with multiple system atrophy (MSA) have a mean survival of 8 to 10 years. Nocturnal stridor has been considered a poor prognostic feature. We analyzed demographic, clinical, and polysomnographic data and obtained follow-up information from 42 patients with MSA (30 with follow-up data) seen in a Sleep Disorders Center. Group I consisted of 17 patients with nocturnal stridor, including seven with daytime stridor. Group II consisted of 25 patients without stridor. Analysis of survival curves of 30 patients with follow-up information showed a significantly shorter survival from the sleep evaluation, but not from disease onset, for patients with stridor compared with those without. Nine of 11 patients with stridor died a median of 2 years from presentation and the only two survivors had undergone tracheostomy. Patients with daytime stridor and immobile vocal cords had especially poor prognoses. However, two of four patients with tracheostomies also died, as did six of 19 without stridor. We postulate that central hypoventilation and its complications may have been responsible for many of these other deaths. We conclude that stridor does carry a poor prognosis in patients with MSA but that there are also other causes of death. We recommend consideration of tracheostomy for patients with MSA who have stridor, but also assessment for central hypoventilation and appropriate management if it is present.

Sympathetically mediated hypertension in autonomic failure

BACKGROUND

Approximately 50% of patients with primary autonomic failure have supine hypertension. We investigated whether this supine hypertension could be driven by residual sympathetic activity.

METHODS AND RESULTS

In patients with multiple system atrophy (MSA) or pure autonomic failure (PAF), we studied the effect of oral yohimbine on seated systolic blood pressure (SBP), the effect of ganglionic blockade (with trimethaphan) on supine SBP and plasma catecholamine levels, and the effect of alpha(1)-adrenoreceptor blockade (phentolamine) on supine SBP. The SBP response to yohimbine was greater in patients with MSA than in those with PAF (area under the curve, 2248+/-543 versus 467+/-209 mm Hg. min; P=0.022). MSA patients with a higher supine SBP had a greater response than those with a lower supine SBP (3874+/-809 versus 785+/-189 mm Hg. min; P=0. 0017); this relationship was not seen in PAF patients. MSA patients had a marked depressor response to low infusion rates of trimethaphan; the response in PAF patients was more variable. Plasma norepinephrine decreased in both groups, but heart rate did not change in either group. At 1 mg/min, trimethaphan decreased supine SBP by 67+/-8 and 12+/-6 mm Hg in MSA and PAF patients, respectively (P<0.0001). Cardiac index and total peripheral resistance decreased in MSA patients by 33.4+/-5.8% and 40.7+/-9.5%, respectively (P=0. 0015). Patients having a depressor response to trimethaphan also had a depressor response to phentolamine. In MSA patients, the pressor response to yohimbine and the decrease in SBP with 1 mg/min trimethaphan were correlated (r=0.98; P=0.001).

CONCLUSIONS

Residual sympathetic activity drives supine hypertension in MSA. It contributes to, but does not completely explain, supine hypertension in PAF.

Toward a primate model of L-dopa-unresponsive parkinsonism mimicking striatonigral degeneration

We developed a primate model of striatonigral degeneration (SND), the neuropathology underlying levodopa-unresponsive parkinsonism associated with multiple systemic atrophy (MSA-P), by sequential systemic administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and 3-nitropropionic acid (3NP) in a Macaca fascicularis monkey. L-Dopa-responsive parkinsonian features emerged after MPTP injections. Subsequent chronic 3NP administration aggravated the motor symptoms and abolished the L-dopa response. In vivo magnetic resonance imaging revealed bilateral striatal lesions. Histopathologically, there was severe dopaminergic cell loss in the substantia nigra pars compacta compared with the control monkey. Furthermore, we observed circumscribed areas of severe neuronal degeneration in the motor striatum. These changes were absent in the control monkey, and they were associated with diffuse metabolic failure as demonstrated by cytochrome oxidase histochemistry. The striatal pathology predominantly involved output pre-pro-enkephalin A- and substance P-containing cells, whereas somatostatin (NADPH-diaphorase)-containing interneurons were relatively spared. Our model therefore reproduced levodopa-unresponsive parkinsonism and SND-like pathologic changes characteristic of MSA-P. The double-lesion primate model of SND may serve as a preclinical test-bed for the evaluation of novel therapeutic strategies in MSA-P.

Anal sphincter EMG does not distinguish between multiple system atrophy and Parkinson's disease

Clinical distinction of multiple system atrophy (MSA) from Parkinson's disease (PD) is often difficult. Several recent reports indicate that objective classification may be accomplished using electromyographic (EMG) testing of the anal or urethral sphincters, but some authors have found that these tests are not reliable for this purpose. We studied 13 patients with PD and 10 with probable MSA, as diagnosed by consensus of four movement disorders specialists, according to accepted clinical criteria. Anal sphincter EMG was performed blind to the clinical diagnosis. We found no significant differences in the mean duration of motor unit potentials (MUPs), mean MUP amplitude, or prevalence of polyphasic potentials, satellite potentials, very long duration MUPs, or spontaneous activity between the two groups. Thus, anal sphincter EMG does not differentiate between PD and MSA.

Orthostatic Hypotension in Multiple System Atrophy

There is no known way to cure multiple system atrophy or even to slow its insidious progression, but there are opportunities to treat many of its symptoms and complications. Of all the autonomic disturbances it causes, orthostatic hypotension is associated with one of the better chances for successful intervention. Milder symptoms may be treated by nonpharmacologic means (eg, changes in diet and activities and compressive maneuvers and devices). Syncopal patients will require treatment with medications. Midodrine is the most effective drug. It is more physiologic and better tolerated, but much more expensive, than fludrocortisone. The latter is often beneficial but frequently causes lower limb edema. Low-dose propranolol is occasionally useful. Other drugs worth trying are indomethacin and intranasal desmopressin. The variety of measures available to treat orthostatic hypotension in multiple system atrophy affords physicians some prospect of easing the suffering of many patients with this otherwise disabling and discouraging disorder.

What clinical features are most useful to distinguish definite multiple system atrophy from Parkinson's disease?

OBJECTIVES

Few studies have attempted to identify what premortem features best differentiate multiple system atrophy (MSA) from Parkinson's disease (PD). These studies are limited by small sample size, clinical heterogeneity, or lack of postmortem validation. We evaluated the sensitivity and specificity of different clinical features in distinguishing pathologically established MSA from PD.

METHODS

One hundred consecutive cases of pathologically confirmed PD and 38 cases of pathologically confirmed MSA in one Parkinson's disease brain bank were included. All cases had their clinical notes reviewed by one observer (AH). Clinical features were divided into two groups: those occurring up to 5 years after onset of disease and those occurring up to death. Statistical analysis comprised multivariate logistic regression analysis to choose and weight key variables for the optimum predictive model.

RESULTS

The selected early features and their weightings were: autonomic features (2), poor initial levodopa response (2), early motor fluctuations (2), and initial rigidity (2). A cut off of 4 or more on the ROC curve resulted in a sensitivity of 87.1% and specificity of 70.5%. A better predictive model occurred if the following features up to death were included: poor response to levodopa (2), autonomic features (2), speech or bulbar dysfunction (3), absence of dementia (2), absence of levodopa induced confusion (4), and falls (4). The resulting ROC curve based on individual scores showed a best cut off score of at least 11 of 17 (sensitivity 90.3%, specificity 92.6%).

CONCLUSIONS

Predictive models may help differentiate MSA and PD premortem. Hitherto poorly recognised features, suggestive of MSA, included preserved cognitive function and absence of psychiatric effects from antiparkinsonian medication. Diagnostic accuracy was higher in those models taking into account all clinical features occurring up to death. Further studies need to be based on new incident cohorts of parkinsonian patients with subsequent neuropathological evaluation.

Towards neurotransplantation in multiple system atrophy: clinical rationale, pathophysiological basis, and preliminary experimental evidence

Multiple system atrophy (MSA) is a neurodegenerative disorder that occurs sporadically and causes parkinsonism, cerebellar, autonomic, urinary, and pyramidal dysfunction in many combinations. Progressive L-dopa-unresponsive parkinsonism due to underlying striatonigral degeneration dominates the clinical syndrome in the majority of cases (MSA-P subtype). MSA-P is characterized pathologically by degenerative changes in somatotopically related areas of the substantia nigra pars compacta and of the putamen. Furthermore, oligodendroglial cytoplasmic inclusions (GCIs) are observed throughout the cortico-striato-pallidocortical loops and may contribute to the basal ganglia dysfunction. Neurotransplantation strategies are of potential interest in this disease, which causes marked and early disability and dramatically reduces life expectancy. A number of experimental MSA-P models have been employed to evaluate neurotransplantation approaches. Sequential nigral and striatal lesions using 6-hydroxydopamine and quinolinic acid (double toxin-double lesion approach) indicate that apomorphine-induced contralateral rotation is abolished by a secondary striatal lesion. Intrastriatal injection of mitochondrial respiratory chain toxins produces secondary excitotoxic striatal lesions combined with retrograde nigral degeneration and therefore provides an alternative single toxin-double lesion approach. Neurotransplantation in MSA-P animal models has been used to improve functional deficits by replacing lost nigral and/or striatal circuitry (neuroregenerative approach). The available data indicate that embryonic mesencephalic grafts alone or combined with striatal grafts partially reverse drug-induced rotation asymmetries without improving deficits of complex motor function. The potential neuroprotective efficacy of embryonic striatal grafts against striatal excitotoxicity is presently under investigation in the double toxin-double lesion MSA-P rat model. Anecdotal clinical evidence in one MSA-P patient misdiagnosed as Parkinson's disease indicates that embryonic mesencephalic grafts produce incomplete clinical benefit. Striatal co-grafts may increase functional improvement. Further experimental studies are required prior to the clinical application of embryonic neurotransplantation in MSA-P. Future research strategies should explore the effect of neurotransplantation in partial MSA-P rat models with less severe nigral and striatal degeneration, the feasibility of a primate model closely mimicking the human disease, and the replication of oligodendroglial dysfunction.