Cerebellar pathology in Friedreich's ataxia: atrophied dentate nuclei with normal iron content.

BACKGROUND: In Friedreich's ataxia (FA) the genetically decreased expression of the mitochondrial protein frataxin leads to disturbance of the mitochondrial iron metabolism. Within the cerebellum the dentate nuclei (DN) are primarily affected. Histopathological studies show atrophy and accumulation of mitochondrial iron in DN. Dentate iron content has been suggested as a biomarker to measure the effects of siderophores/antioxidant treatment of FA. We assessed the iron content and the volume of DN in FA patients and controls based on ultra-high-field MRI (7 Tesla) images. METHODS: Fourteen FA patients (mean age 38.1 yrs) and 14 age- and gender-matched controls participated. Multi-echo gradient echo and susceptibility weighted imaging (SWI) sequences were acquired on a 7 T whole-body scanner. For comparison SWI images were acquired on a 1.5 T MR scanner. Volumes of the DN and cerebellum were assessed at 7 and 1.5 T, respectively. Parametric maps of T2 and T2* sequences were created and proton transverse relaxation rates were estimated as a measure of iron content. RESULTS: In FA, the DN and the cerebellum were significantly smaller compared to controls. However, proton transverse relaxation rates of the DN were not significantly different between both groups. CONCLUSIONS: Applying in vivo MRI methods we could demonstrate significant atrophy of the DN in the presence of normal iron content. The findings suggest that relaxation rates are not reliable biomarkers in clinical trials evaluating the potential effect of FA therapy.

A randomized pilot study of stochastic vibration therapy in spinocerebellar ataxia.

Whole body vibration (WBV) is a biomechanical treatment used widely in professional sports and rehabilitation. We examined the effect of stochastic WBV on ataxia in spinocerebellar ataxia types 1, 2, 3, and 6 (SCA 1, 2, 3 and 6) in a single-center double-blind sham-controlled study. Stochastic WBV was applied on four sequent days, each treatment consisting of five stimulus trains of 60-s duration at a frequency of 6.5 Hz and 60-s resting time between stimuli (n = 17). Patients allocated to the sham group received the same treatment with 1 Hz (n = 15). All patients were rated at baseline and after the last treatment using clinical scores (SARA, SCAFI, and INAS). After treatment, we found significant improvements of gait, posture, and speed of speech in the verum group while limb kinetics and ataxia of speech did not respond. Stochastic WBV might act on proprioceptive mechanisms and could also stimulate non-cerebellar/compensatory mechanisms. But at present, the involved cellular mechanism and the presumed neuronal loops cannot be deciphered. Thus, future work is needed to understand the mechanisms of whole body vibration. Finally, the use of stochastic WBV could provide a supplementation to treat ataxia in SCA and can be combined with physiotherapeutical motor training.

Brain morphometry shows effects of long-term musical practice in middle-aged keyboard players.

To what extent does musical practice change the structure of the brain? In order to understand how long-lasting musical training changes brain structure, 20 male right-handed, middle-aged professional musicians and 19 matched controls were investigated. Among the musicians, 13 were pianists or organists with intensive practice regimes. The others were either music teachers at schools or string instrumentalists, who had studied the piano at least as a subsidiary subject, and practiced less intensively. The study was based on T1-weighted MR images, which were analyzed using deformation-based morphometry. Cytoarchitectonic probabilistic maps of cortical areas and subcortical nuclei as well as myeloarchitectonic maps of fiber tracts were used as regions of interest to compare volume differences in the brains of musicians and controls. In addition, maps of voxel-wise volume differences were computed and analyzed. Musicians showed a significantly better symmetric motor performance as well as a greater capability of controlling hand independence than controls. Structural MRI-data revealed significant volumetric differences between the brains of keyboard players, who practiced intensively and controls in right sensorimotor areas and the corticospinal tract as well as in the entorhinal cortex and the left superior parietal lobule. Moreover, they showed also larger volumes in a comparable set of regions than the less intensively practicing musicians. The structural changes in the sensory and motor systems correspond well to the behavioral results, and can be interpreted in terms of plasticity as a result of intensive motor training. Areas of the superior parietal lobule and the entorhinal cortex might be enlarged in musicians due to their special skills in sight-playing and memorizing of scores. In conclusion, intensive and specific musical training seems to have an impact on brain structure, not only during the sensitive period of childhood but throughout life.

[MSA-QoL: disease-specific questionnaire to assess health-related quality of life in multiple system atrophy: validation of the German translation]. / MSA-QoL: spezifisches Bewertungsinstrument zur Erfassung der Lebensqualität bei Multisystematrophie : Validierung der deutschsprachigen Übersetzung.

BACKGROUND: Multiple system atrophy (MSA) is a rapidly progressive neurodegenerative disorder which causes early sustained disability and quality of life impairment. Recently, a self-reported questionnaire focusing on MSA-specific symptoms (Multiple System Atrophy Quality of Life questionnaire, MSA-QoL) was developed in the English language. This article reports the validation of the German translation of the MSA-QoL. METHODS: Translation of the MSA-QoL was implemented in a 3-tiered approach including a forward translation, a back translation and an independent review. For the validation study 38 consecutive patients with MSA according to the consensus criteria were recruited by the participating centers in a German-Austrian cohort. Data were analyzed using standard psychometric procedures. RESULTS: As determined by the independent review, the German translation of the MSA-QoL was classified as fully equivalent to the English version. The validation study confirmed good psychometric properties of the rating scale. CONCLUSION: The German translation of the MSA-QoL was shown to be a reliable patient-reported rating scale to determine health-related quality of life in MSA patients.

[The genetics of spinocerebellar ataxias]. / Genetik der spinozerebellären Ataxien.

Spinocerebellar ataxias are genetically heterogeneous autosomal dominant ataxia disorders. To date more than 30 different subtypes are known. In Germany particularly SCA1, SCA2, SCA3 and SCA6 are prevalent, as well as the less frequent subtypes SCA5, SCA14, SCA15, SCA17 and SCA28. Genetic causes range from coding repeat expansions (polyglutamine diseases), to non-coding expansions as well as conventional mutations. In some subtypes the genetic background is currently unknown. Age of onset, typical clinical findings and geographic distribution may help to reach a correct diagnosis; however a definitive diagnosis requires molecular genetic testing.

Ataxia with oculomotor apraxia type 2: novel mutations in six patients with juvenile age of onset and elevated serum alpha-fetoprotein.

Ataxia with oculomotor apraxia type 2 (AOA2), a neurodegenerative disorder with juvenile to adolescent onset is caused by mutations within the SENATAXIN gene ( SETX). We performed molecular analyses in six patients showing clinically an AOA2 phenotype and moderate to significant elevated serum alpha-fetoprotein levels. Sequencing the 24 coding exons and flanking intronic sequences revealed 11 novel DNA variations, including seven unknown missense mutations, a dinucleotide deletion, a four-nucleotide deletion affecting the 5' splice site of exon 22 and two sequence variations, which are considered to be polymorphisms. By molecular testing the clinical diagnosis has been confirmed in all patients.

Sporadic adult onset ataxia of unknown etiology : a clinical, electrophysiological and imaging study.

BACKGROUND: The sporadic adult onset ataxias of unknown etiology (SAOA) denote the non-hereditary degenerative adult onset ataxias that are distinct from multiple system atrophy (MSA). OBJECTIVE: To define and characterize the clinical phenotype of sporadic adult onset ataxia of unknown etiology (SAOA). DESIGN: A survey of clinical features, nerve conduction and evoked potentials, autonomic tests, and magnetic resonance imaging (MRI)-based brain morphometry was conducted in patients with SAOA. PATIENTS: Study subjects were a consecutive sample of 27 patients (11 male, 16 female) who met the diagnostic criteria for SAOA (age 55 +/- 13 years; age at disease onset 47 +/- 14 years; disease duration 8 +/- 7 years). RESULTS: All patients presented with a cerebellar syndrome. The most frequent extracerebellar symptoms were decreased vibration sense in 70% and decreased or absent ankle reflexes in 33% of the patients. Nerve conduction studies revealed a polyneuropathy in 26% of the patients. Somatosensory evoked potentials were abnormal in 44%, and central motor conduction time in 17% of patients. Autonomic testing revealed an affected autonomic nervous system in 58% of patients. Voxel-based brain morphometry showed a predominant reduction of gray matter in the cerebellum which was significantly correlated with disease stages. A loss of white matter was found in both middle cerebellar peduncles and the outer edge of the pons. CONCLUSIONS: The data show that SAOA is a predominantly, but not exclusively cerebellar disorder. Clinical, electrophysiological, and imaging findings showed some similarities with multiple system atrophy which raises the question of an overlap of these two disorders.

Voxel-based morphometry and voxel-based relaxometry in multiple system atrophy-a comparison between clinical subtypes and correlations with clinical parameters.

Multiple system atrophy (MSA) is a neurodegenerative disease affecting basal ganglia, brainstem, cerebellum, and intermediolateral cell columns of the spinal cord. Clinically, a cerebellar (MSA-C) and a parkinsonian variant of MSA (MSA-P) are distinguished. We used voxel-based morphometry (VBM) and voxel-based relaxometry (VBR) in 48 MSA patients (32 MSA-C, 16 MSA-P) and 46 controls. In MSA-C, VBM revealed gray matter loss in cerebellum, right thalamus, both putamina and several cortical regions including insular cortex. Gray matter loss in the cerebellum and insular cortex was correlated with disease duration and severity. There was white matter loss in the brainstem, which was correlated with disease duration and severity. VBR analysis in MSA-C showed decreased relaxation rate R2 in cerebellum, pontine brainstem and cortical regions including insular cortex. In MSA-P, gray matter was reduced in cerebellum, dorsal midbrain, both putamina, and several cortical regions including insular cortex. A correlation with disease duration and severity was detected only for some small cortical areas. Direct comparison of MSA-C and MSA-P showed differences only in infratentorial brain regions where structural abnormalities were more pronounced in MSA-C than in MSA-P. In MSA-C, there was a stronger reduction of gray matter in the basal parts of the cerebellum, of white matter in the brainstem and of the relaxation rate R2 in the cerebellum and brainstem.

A simple and fast method for the preparation of n.c.a. 2-[18F]F-A85380 for human use.

2-[18F]F-A85380 is the first subtype selective PET-radiotracer to visualize the distribution of alpha4beta2 nicotinic acetylcholine receptors in human brain in vivo. We investigated a fast and safe automated production of 2-[18F]F-A85380 by purification of the BOC-protected intermediate product with a combination of solid phase extraction cartridges. After deprotection, adjustment of the pH and sterile filtration n.c.a. 2-[18F]F-A85380 was applicable for the use in human studies with a high specific activity and an overall radiochemical yield of 55% in 35 minutes.

Dopamine transporter SPECT in patients with mitochondrial disorders.

BACKGROUND: Mitochondrial disorders may affect basal ganglia function. In addition, decreased activity of complex I of the mitochondrial electron transport chain has been linked to the pathogenesis of dopaminergic cell loss in Parkinson's disease. Objective : To investigate the dopaminergic system in patients with known mitochondrial disorders and complex I deficiency. METHODS: Dopamine transporter density was studied in 10 female patients with mitochondrial complex I deficiency by (123)I-FP-CIT (N-beta-fluoropropyl-2beta-carbomethyl-3beta-(4-iodophenyl)-nortropane) SPECT. RESULTS: No differences in (123)I-FP-CIT striatal binding ratios were observed and no correlation of the degree of complex I deficiency and striatal binding ratios could be detected. CONCLUSIONS: These data argue against the possibility that mitochondrial complex I deficiency by itself is sufficient to elicit dopaminergic cell loss.

Imaging of central nAChReceptors with 2-[18F]F-A85380: optimized synthesis and in vitro evaluation in Alzheimer's disease.

In vivo labeling of the nicotinic acetylcholine receptors (nAChR) could be a useful tool for early diagnosis of neurodegenerative disorders. 2-[18F]F-A85380 (2-[18F]Fluoro-3-[2(S)-2-azetidinylmethoxy]pyridine), a ligand with high affinity to the beta2 subunit of the nAChRs, has been shown to label neurons in the nAChR-rich thalamus, cortex and striatum in baboons. We report an optimized synthesis resulting in an uncorrected yield of 58% in 45 min (precursor 2), enabling efficient production intended for clinical use. Incubation of normal rat brain sections with 2-[18F]F-A85380 with subsequent autoradiographic analyses showed the expected distribution in nAChR areas. In human brain sections of Alzheimer's disease (AD) a decrease of 2-[18F]F-A85380 uptake to 36% of the control group was measured in the thalamus and also in the occipital cortex. These findings suggest that 2-[18F]F-A85380 is a promising PET-ligand in the diagnosis of AD.