A study of parkinsonism in multiple system atrophy: clinical and MRI correlation

Brain MRI of multiple system atrophy of cerebellar type: a prospective study with implications for diagnosis criteria

AIM

The second consensus statement for the diagnosis of multiple system atrophy type cerebellar (MSA-C) includes pons and middle cerebellar peduncle (MCP) atrophy as MRI features. However, other MRI abnormalities such as MCP hyperintensity, hot cross bun sign (HCB), putaminal hypointensity and hyperintense putaminal rim have been described.

OBJECTIVES

To evaluate, in patients with sporadic late-onset cerebellar ataxia (SLOCA), the discriminative value of several MRI features for the diagnosis of MSA-C, to follow their evolution during the course of MSA-C, and to search for correlations between these MRI features and clinical signs.

METHODS

Consecutive patients referred for SLOCA underwent comprehensive clinical evaluation and laboratory investigations, brain MRI, DaTscan and a 1-year follow-up.

RESULTS

Among 80 patients, 26 had MSA-C, 22 another diagnosis, and 32 no diagnosis at the end of the follow-up. At baseline, MCP hyperintensity and HCB were more frequent in patients finally diagnosed with MSA-C than in other patients with SLOCA (p < 0.0001), and had the highest specificity (98.5%) and positive predictive value (91.7%) for the diagnosis of MSA-C, compared to all other MRI signs. The most relevant MRI sequence regarding HCB sign was the T2-proton density (DP) weighted. All MRI features were more frequent with disease duration. No correlation was found between any MRI feature and neither clinical data, nor dopaminergic neuronal loss (p = 0.5008), except between vermis atrophy and UPDRSIII score.

CONCLUSION

MCP hyperintensity and HCB sign should be added into the list of additional features of possible MSA-C. MRI signal abnormalities suggestive of MSA-C should be searched for in suitable sequence.

Tremor in Multiple System Atrophy - a review

BACKGROUND

Multiple system atrophy (MSA) is a rare neurodegenerative movement disorder characterized by a rapidly progressive course. The clinical presentation can include autonomic failure, parkinsonism, and cerebellar signs. Differentiation from Parkinson's disease (PD) is difficult if there is levodopa-responsive parkinsonism, rest tremor, lack of cerebellar ataxia, or mild/delayed autonomic failure. Little is known about tremor prevalence and features in MSA.

METHODS

We performed a PubMed search to collect the literature on tremor in MSA and considered reports published between 1900 and 2013.

RESULTS

Tremor is a common feature among MSA patients. Up to 80% of MSA patients show tremor, and patients with the parkinsonian variant of MSA are more commonly affected. Postural tremor has been documented in about half of the MSA population and is frequently referred to as jerky postural tremor with evidence of minipolymyoclonus on neurophysiological examination. Resting tremor has been reported in about one-third of patients but, in contrast to PD, only 10% show typical parkinsonian "pill-rolling" rest tremor. Some patients exhibit intention tremor associated with cerebellar dysmetria. In general, MSA patients can have more than one tremor type owing to a complex neuropathology that includes both the basal ganglia and pontocerebellar circuits.

DISCUSSION

Tremor is not rare in MSA and might be underrecognized. Rest, postural, action and intention tremor can all be present, with jerky tremulous movements of the outstretched hands being the most characteristic. However, reviewing the data on tremor in MSA suggests that not every shaky movement satisfies tremor criteria; therefore, further studies are needed.

Putaminal magnetic resonance imaging features at various magnetic field strengths in multiple system atrophy

We delineated the effects of magnetic field strength on signal intensities to facilitate the specific findings of multiple system atrophy (MSA). Fifteen patients with probable MSA were imaged by 0.35T fast spin-echo (FSE), 1.5T FSE, and 3.0T FSE using a consistent protocol, testing all field strengths on the same day. Sixty patients with probable Parkinson's disease (PD) also underwent imaging. Moderate or marked hyperintensity at the dorsolateral outer putaminal margin, hyperintensity of the putaminal body, hypointensity relative to the globus pallidus at the dorsolateral putaminal margin, and infratentorial signal changes were evaluated as specific findings for MSA. As the field strength increased, the occurrence of hyperintensity both at the dorsolateral outer putaminal margin and of the putaminal body decreased, while the occurrence of hypointensity at the dorsolateral putaminal margin increased in MSA. The occurrence of uniform mild hyperintensity of the outer putaminal margin was evident in 7% at 0.35T, 40% at 1.5T, and 47% at 3.0T in MSA and in 5% at 0.35T, 60% at 1.5T, and 75% at 3.0T in PD. However, no PD patients showed hyperintensity at the dorsolateral outer putaminal margin and that of the putaminal body. Putaminal magnetic resonance imaging (MRI) findings in MSA were altered considerably by magnetic field strength. The severity and distribution of signal changes are important for assessing putaminal MRI findings in MSA.

Multiple system atrophy

BACKGROUND

It has been almost 4 decades since the descriptions of the 3 parts of multiple system atrophy (MSA) have taken place, characterized clinically by dysautonomia, parkinsonism, and cerebellar dysfunction. The discovery of a distinctive pathologic maker has finally provided the conceptual synthesis of these 3 entities into the universal designation of MSA as a distinct disease process with a complex combination of clinical presentations. Although advances have been made in terms of awareness and knowledge concerning the clinical features and pathophysiology of MSA, it remains challenging for neurologists who treat these patients to differentiate MSA from its mimics as well as providing them with effective treatment.

REVIEW SUMMARY

The aim of this review is to provide an overview of the advances in the knowledge of the disease, to highlight typical features useful for the recognition of its entity, and to enlist different treatment options.

CONCLUSION

Despite the fact that there is still no treatment modality that can alter the disease progression, a number of useful symptomatic treatment measures are available and should be offered to patients to ameliorate the nonmotor features of MSA and even the motor features that may at least transiently respond to treatment.

Cortical atrophy in the cerebellar variant of multiple system atrophy: a voxel-based morphometry study

This study aimed to determine in vivo the atrophy patterns in clinically established cerebellar variant of multiple-system atrophy (MSA-C) using voxel-based morphometry (VBM). Thirteen patients with MSA-C (12 probable, 1 possible) and 13 healthy controls matched for age and sex were included. High-resolution MR images were acquired with a 1.5 T scanner. Images were normalized onto a study-specific template, segmented into the tissue compartments, modulated with the Jacobian determinants, and finally smoothed with a Gaussian kernel filter of 10 mm. The general linear model was used to assess statistical differences in gray and white matter. Infratentorial atrophy was observed in the cerebellar hemispheres, vermis, mesencephalon, and pons of MSA-C patients. Supratentorial volume loss was found in orbitofrontal and mid-frontal regions as well as in temporomesial and insular areas of both hemispheres. A negative correlation was observed between a cerebellar ataxia score and the volume of cerebellar hemispheres, peduncles, and pons. To compare this atrophy pattern to that of spinocerebellar ataxia (SCA2), which was previously reported by our group, a conjunction analysis was assessed. We observed a volume loss shared by both disorders comprising the cerebellum, vermis, pons, mesencephalon, orbitofrontal, mid-frontal, and temporomesial cortex of both hemispheres as well as the left insular cortex.

Effect of object transport on grasp coordination in multiple system atrophy

We examined the effects of the parkinsonian variant of multiple-system atrophy (MSA-P) on grasp and forward transport and release of an object. Twelve patients with MSA-P and 10 age-matched control subjects performed the task with each of three object weights (200, 400, 800 gm). Subjects moved at a self-selected pace using a precision grip. The grip (normal) and load (tangential) forces and the object position were recorded. Results indicate subjects with MSA-P have temporal and force coordination deficits. Temporal delays were seen in all subjects with MSA-P, leading to prolonged overall movement times compared to control subjects. These delays occurred throughout the task, with significantly longer transport phases and delays releasing the object. Despite demonstrating an appropriate anticipatory scaling of forces, with increasing grip and load forces for heavier weights, force coordination was compromised in subjects with MSA-P. These subjects generated significant negative load forces prior to transporting the object. In addition, during the transport phase, subjects with MSA-P generated highly variable grip forces. Overall, the results indicate that subjects with MSA-P demonstrate bradykinesia and difficulty coordinating components of an object transport task.

Comparison of magnetic resonance imaging in subtypes of multiple system atrophy

Some abnormal findings in routine MRI have been proposed as helpful discriminators for distinguishing multiple system atrophy (MSA) from Parkinson's disease (PD). However, what the most distinguishing MRI findings for MSA-p (parkinsonism dominant) or MSA-c (cerebellar dominant) are separately has not been systematically analyzed. To determine what the most helpful discriminators for MSA-p or MSA-c are and whether those findings are correlated with the presence of parkinsonism or cerebellar dysfunction, we compared 10 previously reported MRI findings in 36 patients with probable MSA-p, 27 patients with probable MSA-c and 30 patients with PD separately. In our results, hyperintense rim and putaminal atrophy among supratentorial parameters and the parameters of infratentorial atrophy were significantly prominent in MSA-p comparing to PD. Hyperintense rim showed the highest specificity in MSA-p patients (90.0%) with relatively suboptimal sensitivity (72.2%). In MSA-c, all infratentorial parameters had strong discriminating power comparing to PD. Signal increase in the middle cerebellar peduncle showed the highest specificity (100%) and had fair sensitivity (85.2%) in MSA-c. Compared between MSA-p and MSA-c, supratentorial parameters were not valid to differentiate MSA-c from MSA-p except for putaminal atrophy. On the contrary, infratentorial parameters were good for distinguishing MSA-c from MSA-p except dilatation of the fourth ventricle. Parkinsonism was not correlated with a hyperintense rim, but cerebellar symptoms were correlated with signal increase in the middle cerebellar peduncle. Our findings suggest the characteristic MRI can be helpful for differentiating MSA-p and MSA-c from PD, respectively, although they do not reflect the presence or lateralization of parkinsonism.

Avaliação da doença de Parkinson pela ressonância magnética

OBJETIVO: Avaliar a doença de Parkinson pela ressonância magnética. MATERIAIS E MÉTODOS: De outubro de 1999 a outubro de 2002, foram estudados 42 pacientes com parkinsonismo, por meio de um aparelho de ressonância magnética de 1,5 T. Os pacientes foram divididos em dois grupos: grupo com doença de Parkinson (n = 26) e grupo com síndrome parkinsoniana atípica (n = 16), sendo os resultados comparados com um grupo controle (n = 18). Foram avaliadas as seguintes variáveis: espessura da pars compacta do mesencéfalo, grau de hipointensidade de sinal no putâmen, grau de atrofia cerebral, lesões no mesencéfalo, lesões na substância branca e a presença de lesão na borda póstero-lateral do putâmen. A análise estatística dos dados foi realizada, com a utilização do programa SPSS. RESULTADOS: A média de idade foi de 58,2 anos nos grupos com doença de Parkinson e controle, e 60,5 anos no grupo com síndrome parkinsoniana atípica. Os pacientes com doença de Parkinson e síndrome parkinsoniana atípica apresentaram redução da espessura da pars compacta e maior grau de hipointensidade de sinal no putâmen. O grau de atrofia cerebral foi maior nos pacientes com síndrome parkinsoniana atípica. As lesões no mesencéfalo e na substância branca foram semelhantes entre os grupos. O sinal hiperintenso na borda póstero-lateral do putâmen foi um achado pouco freqüente na população estudada, mas sugestivo de atrofia de múltiplos sistemas. CONCLUSÃO: Desta forma, a ressonância magnética detectou alterações morfológicas cerebrais que podem auxiliar no diagnóstico por imagem das síndromes parkinsonianas.

Coordination of fingertip forces during precision grasping in multiple system atrophy

While the pathology and autonomic nervous system components of multiple system atrophy (MSA) have been well described, little is known about the associated motor dysfunction. One prominent feature of MSA is parkinsonism, although ataxias and pyramidal tract signs are frequently present. To investigate the nature of motor deficits in MSA, a natural grip-lift movement requiring a precision grasp was used to examine force coordination. Subjects were asked to grasp an instrumented object using the fingertips of the thumb and index finger and lift it 10 cm above the table surface. Subjects with MSA demonstrated a prolonged duration between object contact and initiation of the lifting drive that increased with the weight of the object. During this period these subjects produced large grasping forces generating a significant portion of the eventual grip force employed to hold the object. In contrast, control subjects generated grip and load forces in parallel after establishing contact with the object. Therefore, subjects with MSA showed a disrupted performance on both the sequential (grasp, then lift) and simultaneous (grip and load force development) portions of this task. Only after initiation of the vertical lifting drive did subjects with MSA generate forces in a similar manner to control subjects. These findings demonstrate that subjects with MSA exhibit a disrupted coordination of grasp and could suggest a general deficit in motor control resulting from multi-focal neural degeneration.

Magnetization transfer measurements of brain structures in patients with multiple system atrophy

To determine whether magnetization transfer imaging (MTI) demonstrates abnormalities in the brain structures of patients with multiple system atrophy (MSA), we examined 12 patients with clinically probable MSA and 11 control subjects. We calculated magnetization transfer ratios (MTRs) using region of interest analysis from MTI and assessed abnormal signal changes on T2-weighted images. MTRs of the base of the pons, middle cerebellar peduncle, putamen, and white matter of the precentral gyrus were significantly lower in the MSA patients than in the controls. Abnormal signal changes on T2-weighted images were observed in the base of the pons (n = 6), middle cerebellar peduncle (n = 7), and putamen (n = 7). MTRs of regions with abnormal signals were significantly lower than those of regions without abnormal signals and those in the controls. Even the MTRs of the regions without abnormal signals were lower than those in the controls. MTRs of the pyramidal tract, including white matter of the precentral gyrus, posterior limb of the internal capsule, cerebral peduncle, and base of the pons, were significantly lower in patients with pyramidal tract sign (n = 7) than in the controls. Patients with asymmetrical parkinsonism (n = 5) showed significantly lower MTRs in the putamen contralateral to the predominant side of parkinsonian symptoms than the ipsilateral side, although asymmetry of abnormal signal changes on T2-weighted images was not evident in more than half of those patients. This study showed that MTI demonstrates abnormalities in the brains of patients with MSA that seem to reflect underlying pathological changes and that the pathological changes detected by MTI seem to give rise to clinical symptoms. This study also showed that the abnormalities are detected more sensitively and over a larger area by MTI than by conventional magnetic resonance imaging.

Increased brain histamine levels in Parkinson's disease but not in multiple system atrophy

We investigated histamine concentration in post-mortem brain samples of patients with Parkinson's disease (PD, n = 24), multiple system atrophy (MSA, n = 8) and age-matched controls (n = 27). Histamine concentrations were significantly increased in the putamen (to 159% of the control mean), substantia nigra pars compacta (to 201%), internal globus pallidus (to 234%) and external globus pallidus (to 200%), i.e. in areas which play a crucial role in the motor behaviour and which show typical functional alterations in PD. In MSA no significant differences were seen. Tele-methylhistamine (histamine metabolite) concentrations were unchanged in PD. These results indicate that histamine concentration, but not its metabolism is increased in PD, but not in MSA. This finding may have implications in developing new drug therapies for PD and in differential diagnosis between PD and MSA.

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.

Phosphorus magnetic resonance spectroscopy in multiple system atrophy and Parkinson's disease

We performed in vivo phosphorus magnetic resonance spectroscopy on the occipital lobes of 15 patients with multiple system atrophy (MSA; eight with olivopontocerebellar atrophy [OPCA] and seven with the striatonigral degeneration variant [SND]), 13 patients with idiopathic Parkinson's disease (PD), and 16 age-matched healthy subjects. The MSA group showed significantly reduced phosphocreatine (PCr), increased inorganic phosphate (Pi), and unchanged cytosolic free [Mg2+], and pH. We did not find any significant difference between the OPCA and SND variants. However, patients with PD showed significantly increased content of Pi, decreased cytosolic free [Mg2+], and unchanged [PCr] and pH. Comparing the MSA and PD groups, [PCr] was significantly lower in MSA than in PD, whereas cytosolic free [Mg2+] was significantly lower in PD. Despite a certain degree of overlap of [PCr] and [Mg2+] values between the two groups, by considering both variables at the same time it was possible to classify correctly 93% of cases by discriminant analysis. We conclude that phosphorus magnetic resonance spectroscopy discloses abnormal phosphate metabolite and ion contents in both MSA and PD, respectively, and may provide noninvasive diagnostic help to differentiate MSA from PD.

Clinical usefulness of magnetic resonance imaging in multiple system atrophy

OBJECTIVES

To determine the sensitivity, specificity, and positive predictive values of a selection of abnormal findings in the putamen and infratentorial structures on routine magnetic resonance imaging for distinguishing between multiple system atrophy, idiopathic Parkinson's disease, and age matched controls.

PATIENTS AND METHODS

Two neuroradiologists blindly and independently rated axial T2 weighted and proton density MRI of 44 patients with multiple system atrophy, 47 patients with idiopathic Parkinson's disease, and 45 controls. High field (1.5 T) scans were available in 16 patients with multiple system atrophy, 15 patients with idiopathic Parkinson's disease, and 16 controls. All other patients had 0.5 T scans.

RESULTS

On both 0.5 and 1.5 T scans the following items had high specificity but low sensitivity: putaminal atrophy, a hyperintense putaminal rim, and infratentorial signal change. Finding any infratentorial abnormality gave higher sensitivity but lower specificity. Putaminal isointensity or hypointensity relative to globus pallidus, absolute putaminal hypointensity, and altered size of the olives were not useful discriminators. The overall sensitivity was 73% on 0.5 T and 88% on 1.5 T scans. The specificities of these findings for multiple system atrophy in comparison to idiopathic Parkinson's disease and controls on 0.5 T were 95% and 100% respectively, and on 1.5 T were 93% and 91% respectively. Finding any of the described abnormalities on MRI gave a positive predictive value of 93% on the 0.5 T machine, and 85% on the 1.5 T scanner.

Neuroimaging and neuropsychology of the striatum. Bridging basic science and clinical practice

Neuroimaging and neuropsychology are complementary disciplines that provide powerful means for assessing the structure and function of corticostriatal systems. Findings from four model basal ganglia disorders--OCD, TS, HD, and PD--are reviewed. This survey is intended as a vehicle for illustrating the breadth of current clinical and research applications, as well as the potential for future advances. The perspectives brought by neuroimaging and neuropsychology serve as a natural bridge from the basic neuroscience to the clinical practice articles in this issue.

Survival in multiple system atrophy: a study of prognostic factors in 59 cases

The various clinical features of multiple system atrophy (MSA) make the diagnosis of the disease difficult, especially in its early stages, when signs of differentiated neuroanatomical system involvement have not yet appeared. Mortality studies may be affected by the variability of the diagnostic criteria and selection bias. We used strict clinical and MRI criteria to diagnose MSA in 59 patients. Patients with parkinsonian and cerebellar onset were compared. Median survival time from the onset of the first motor symptom was 7.5 years. Our results indicated a trend (P = 0.09) for the Northwestern University Disability Scale score to correlate with mortality, but we failed to find other characteristics identifying subgroups or predictors for survival.

Multiple system atrophy presenting as parkinsonism: clinical features and diagnostic criteria

To evaluate the possibility that parkinsonian signs may be the only presenting feature of multiple system atrophy (MSA), parkinsonian patients were studied who had no atypical clinical signs and had no symptoms of autonomic dysfunction, but who reported that they had not experienced the anticipated good response to dopaminergic treatment. These stringent criteria identified 20 patients from a series of 298 consecutive parkinsonian outpatients. The following clinical pointers were analysed: (a) rate of disease progression; (b) symmetry of parkinsonian symptoms and signs; (c) occurrence of resting tremor during the first three years from onset. In addition, all patients underwent (d) acute and chronic challenge with dopaminergic drugs; (e) cardiovascular reflex autonomic function tests; (f) high field MRI. Rapid progression of disease was seen in 45% of patients, onset was symmetric in 25%, tremor was absent at onset in 70%, response to dopaminergic drug challenges was inadequate in 40%, abnormal cardiovascular reflexes occurred in 50%, and some abnormal MRI finding occurred in 35% of cases. Each of these features was equally weighted by giving to each patient a 0 to 6 point score corresponding to the number of abnormal findings. Fifteen patients scoring higher than 1 were considered at risk for having MSA: five of them were classified as clinically possible (score 2), six as clinically probable (score 3-4), and four patients were classified as clinically definite multiple system atrophy (score 5). The six pointers considered were variably combined in each patient, none of them being universally abnormal in patients with high scores. The patients were followed up for a mean 2.1 (SEM 0.65) years. All but one of the 10 patients prospectively classified as probable or definite MSA developed unequivocal clinical signs of fully symptomatic MSA. A receiver operator characteristic cure was plotted for the prospective score based on follow up diagnosis. The best compromise for trade off between sensitivity and specificity was a cut off value at a score of 3. The sensitivity and specificity of the individual pointers considered to predict fully symptomatic MSA varied considerably, and no single item could predict whether patients presenting with just parkinsonian signs went on during the two year follow up period to develop fully symptomatic MSA. Instead, the number of abnormalities offered a predictive value for the clinical prognosis of these parkinsonian patients.