Striatal metabolism and psychomotor speed as predictors of motor onset in Huntington's disease.

The clinical diagnosis of Huntington's disease (HD) is based on the motor symptoms, although these can be preceded by cognitive and behavioral changes. Biomarker studies have shown that structural imaging modalities are useful biomarkers of HD onset, while functional imaging measures have been studied less often for this purpose. Our aim was to investigate the combined value of 18-fluorodesoxyglucose (FDG)-PET and cognitive measures as biomarkers of HD onset. Twenty-two premanifest mutation carriers of HD (PMCs) and 11 healthy controls were assessed twice with FDG-PET scan, neurological and neuropsychological assessments over a 2-year interval. Seventeen PMCs had an additional third neurological evaluation, 10 years after baseline. Disease load was defined as the probability of motor onset within 5 years. Metabolism in putamen, caudate and pallidum of PMCs was significantly lower than that of controls, at both assessments. Almost half of the PMCs had converted to manifest HD 10 years later and all converters had low average or abnormal putaminal metabolism at 2 year follow-up. In contrast, all PMCs with normal putaminal metabolism at 2 year follow-up remained premanifest during the following 8 years. Furthermore, glucose metabolism of putamen explained a substantial part of the variance in disease load. A composite score of psychomotor tests contributed significantly to the prediction model as well, while cognitive performance was comparable for PMCs and controls. We conclude that in future clinical trials a combination of psychomotor tests and putaminal glucose metabolism may be used to identify PMCs close to motor onset of HD.

Metabolic network as a progression biomarker of premanifest Huntington's disease.

BACKGROUND: The evaluation of effective disease-modifying therapies for neurodegenerative disorders relies on objective and accurate measures of progression in at-risk individuals. Here we used a computational approach to identify a functional brain network associated with the progression of preclinical Huntington's disease (HD). METHODS: Twelve premanifest HD mutation carriers were scanned with [18F]-fluorodeoxyglucose PET to measure cerebral metabolic activity at baseline and again at 1.5, 4, and 7 years. At each time point, the subjects were also scanned with [11C]-raclopride PET and structural MRI to measure concurrent declines in caudate/putamen D2 neuroreceptor binding and tissue volume. The rate of metabolic network progression in this cohort was compared with the corresponding estimate obtained in a separate group of 21 premanifest HD carriers who were scanned twice over a 2-year period. RESULTS: In the original premanifest cohort, network analysis disclosed a significant spatial covariance pattern characterized by progressive changes in striato-thalamic and cortical metabolic activity. In these subjects, network activity increased linearly over 7 years and was not influenced by intercurrent phenoconversion. The rate of network progression was nearly identical when measured in the validation sample. Network activity progressed at approximately twice the rate of single region measurements from the same subjects. CONCLUSION: Metabolic network measurements provide a sensitive means of quantitatively evaluating disease progression in premanifest individuals. This approach may be incorporated into clinical trials to assess disease-modifying agents. TRIAL REGISTRATION: Registration is not required for observational studies. FUNDING: NIH (National Institute of Neurological Disorders and Stroke, National Institute of Biomedical Imaging and Bioengineering) and CHDI Foundation Inc.

[Cerebellar dysfunction due to pneumonia caused by Legionella pneumophila]. / Cerebellaire stoornissen door Legionella-pneumonie.

BACKGROUND: Legionnaires' disease is frequently complicated by extrapulmonary symptoms such as neurological abnormalities. Cerebellar disorders are rare, but can be long-lasting and disabling. CASE DESCRIPTION: A 57-year-old male developed severe cerebellar disorders such as dysarthria and ataxia after being hospitalized for pneumonia. Despite an extensive diagnostic work-up, no explanation for the cerebellar symptoms could be found. The patient was transferred to a rehabilitation facility. Repeated serological tests revealed infection with Legionella, which was most probably the cause of the cerebellar dysfunction. CONCLUSION: Cerebellar disorders are a rare complication of Legionnaires' disease. The pathogenesis is unknown. There is no diagnostic test that proves or excludes cerebellar involvement in an infection caused by Legionella. The treatment is supportive and recovery can take months or even years.

Typical cerebral metabolic patterns in neurodegenerative brain diseases.

The differential diagnosis of neurodegenerative brain diseases on clinical grounds is difficult, especially at an early disease stage. Several studies have found specific regional differences of brain metabolism applying [(18)F]-fluoro-deoxyglucose positron emission tomography (FDG-PET), suggesting that this method can assist in early differential diagnosis of neurodegenerative brain diseases.We have studied patients who had an FDG-PET scan on clinical grounds at an early disease stage and included those with a retrospectively confirmed diagnosis according to strictly defined clinical research criteria. Ninety-six patients could be included of which 20 patients with Parkinson's disease (PD), 21 multiple system atrophy (MSA), 17 progressive supranuclear palsy (PSP), 10 corticobasal degeneration (CBD), 6 dementia with Lewy bodies (DLB), 15 Alzheimer's disease (AD), and 7 frontotemporal dementia (FTD). FDG PET images of each patient group were analyzed and compared to18 healthy controls using Statistical Parametric Mapping (SPM5).Disease-specific patterns of relatively decreased metabolic activity were found in PD (contralateral parietooccipital and frontal regions), MSA (bilateral putamen and cerebellar hemispheres), PSP (prefrontal cortex and caudate nucleus, thalamus, and mesencephalon), CBD (contralateral cortical regions), DLB (occipital and parietotemporal regions), AD (parietotemporal regions), and FTD (frontotemporal regions).The integrated method addressing a spectrum of various neurodegenerative brain diseases provided means to discriminate patient groups also at early disease stages. Clinical follow-up enabled appropriate patient inclusion. This implies that an early diagnosis in individual patients can be made by comparing each subject's metabolic findings with a complete database of specific disease related patterns.

Pulsed high-dose dexamethasone versus standard prednisolone treatment for chronic inflammatory demyelinating polyradiculoneuropathy (PREDICT study): a double-blind, randomised, controlled trial.

BACKGROUND: Pulsed high-dose dexamethasone induced long-lasting remission in patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) in a pilot study. The PREDICT study aimed to compare remission rates in patients with CIDP treated with high-dose dexamethasone with rates in patients treated with standard oral prednisolone. METHODS: In eight neuromuscular centres in the Netherlands and one in the UK, patients aged 18 years or older who had newly diagnosed definite or probable CIDP were randomly assigned to a treatment regimen of either pulsed high-dose dexamethasone or standard oral prednisolone. Randomisation was done with a random number generator. The primary outcome measure was remission at 12 months, defined as improvement of at least three points on the Rivermead mobility index and improvement of at least one point on the inflammatory neuropathy cause and treatment disability scale. Analysis was by intention to treat. This trial is registered with Current Controlled Trials, number ISRCTN07779236. FINDINGS: Between December, 2003, and December, 2008, 40 patients were treated: 24 received dexamethasone and 16 received prednisolone. At 12 months, 16 patients were in remission: ten in the dexamethasone group and six in the prednisolone group (odds ratio [OR] 1.2, 95% CI 0.3-4.4). Most adverse events were minor and did not differ substantially between treatment groups; however, sleeplessness and Cushing's face occurred more often in the prednisolone group. INTERPRETATION: Pulsed high-dose dexamethasone treatment did not induce remission more often than prednisolone treatment. A substantial proportion of patients were in remission at 12 months in both treatment groups. High-dose dexamethasone could be considered as induction therapy in CIDP, but comparison with intravenous immunoglobulin treatment is needed. FUNDING: The Prinses Beatrix Fonds (MAR01-0213) and the Department of Neurology, Academic Medical Center.

Blood-brain barrier P-glycoprotein function decreases in specific brain regions with aging: a possible role in progressive neurodegeneration.

Cerebrovascular P-glycoprotein (P-gp) acts at the blood-brain barrier (BBB) as an active cell membrane efflux pump for several endogenous and exogenous compounds. Age-associated decline in P-gp function could facilitate the accumulation of toxic substances in the brain, thus increasing the risk of neurodegenerative pathology with aging. We hypothesised a regionally reduced BBB P-gp function in older healthy subjects. We studied cerebrovascular P-gp function using [(11)C]-verapamil positron emission tomography (PET) in seventeen healthy volunteers with age 18-86. Logan analysis was used to calculate the distribution volume (DV) of [(11)C]-verapamil in the brain. Statistical Parametric Mapping was used to study specific regional differences between the older compared with the younger adults. Older subjects showed significantly decreased P-gp function in internal capsule and corona radiata white matter and in orbitofrontal regions. Decreased BBB P-gp function in those regions could thus explain part of the vulnerability of the aging brain to white matter degeneration. Moreover, decreased BBB P-gp function with aging could be a mechanism by which age acts as the main risk factor for the development of neurodegenerative disease.

The syndrome of headache with neurologic deficits and cerebrospinal fluid lymphocytosis mimicking acute ischemic stroke.

Headache with neurologic deficits and cerebrospinal fluid lymphocytosis is a benign condition with a transient ischemic attack-like presentation. We present a case of a 22-year-old man with episodes of right-sided weakness, global dysphasia, and right-sided homonymous hemianopsia associated with frequent vomiting. Systemic thrombolytic therapy was considered. A subsequent magnetic resonance image with diffusion-weighted images revealed normal findings. A diagnosis of headache with neurologic deficits and cerebrospinal fluid lymphocytosis was made based mainly on clinical symptoms and cerebrospinal fluid analysis. With the current pressure on "door-to-needle" time for thrombolysis, it is important to keep an open eye to stroke mimics and exclude them if possible. We, therefore, strongly advise considering noninvasive magnetic resonance diffusion-weighted imaging in patients with unusual presentations (e.g., the vomiting in our patient) before thrombolysis.

1H magnetic resonance spectroscopy in preclinical Huntington disease.

Huntington disease (HD) is a hereditary brain disease, causing progressive deterioration after a preclinical phase. The pathophysiology of early brain abnormalities around disease onset is largely unknown. Some preclinical mutation carriers (PMC) show structural or metabolic changes on brain imaging but the most sensitive imaging modality has not been determined. (1)H magnetic resonance spectroscopy (MRS) studies in PMC have reported conflicting results. We studied 19 PMC and 8 controls with MRS and determined relative metabolite peak areas for choline, creatine and N-acetyl aspartate (NAA) in putamen and thalamus. We found no significant differences in metabolite signals between PMC and controls. Decreases in the NAA concentration ratio of putamen relative to thalamus correlated weakly (R(2)=0.22, p=0.04) with increases in the product of CAG repeat length and age, a predictor of striatal damage. Since other brain imaging methods have shown changes in these study subjects, MRS is not a very sensitive detector of early HD brain pathology.

Blood-brain barrier dysfunction in parkinsonian midbrain in vivo.

Parkinson's disease (PD) is associated with a loss of neurons from the midbrain. The cause of PD is unknown, but it is established that certain neurotoxins can cause similar syndromes. The brain is normally protected from these noxious blood-borne chemicals by the blood-brain barrier which includes specialized proteins on the inside of blood vessels in the brain. These act as molecular efflux pumps and P-glycoprotein (P-gp) is an abundant representative. Vulnerability to PD appears codetermined by the genotype for the P-gp gene. We hypothesized that PD patients have reduced P-gp function in the blood-brain barrier. We used positron emission tomography to measure brain uptake of [(11)C]-verapamil, which is normally extruded from the brain by P-gp. Here, we show significantly elevated uptake of [(11)C]-verapamil (18%) in the midbrain of PD patients relative to controls. This is the first evidence supporting a dysfunctional blood-brain barrier as a causative mechanism in PD.