A gait-based paradigm to investigate central body representation in cervical dystonia patients

BACKGROUND

Cervical dystonia (CD) is a common adult-onset idiopathic form of dystonia characterized by an abnormal head posture caused by an excessive activity of the neck muscles. The position of the head is important to direct viewpoint in the rounding environment, and the body orientation, during gait, must be coherent with the subjective straight ahead (SSA). An alteration of the SSA, as in the case of CD patients, could affect gait when visual input is not available. The aim of this study was to probe the behavior of patients with CD during blindfolded walking, investigating the ability to walk straight ahead based only on somatosensory and vestibular information.

METHODS

In this observational cross-sectional study, patients with CD and healthy control subjects (HC) were compared. All participants were evaluated through a gait analysis during blindfolded walking on a GAITRite carpet, relying on their own sense of straightness.

RESULTS

Patients with CD showed lower values of path length (p < 0.001), a lower number of steps on the carpet (p < 0.001). A higher number of CD patients deviated during the task, walking out of the carpet, (p < 0.005) compared to HS. No relation was found between the dystonic side and the gait trajectory deviation. A significant correlation was found between pain symptom and gait performance.

CONCLUSIONS

CD patients showed dysfunctions in controlling dynamic body location during walking without visual afferences, while the dystonic side does not seem to be related to the lateral deviation of the trajectory. Our results would assume that a general proprioceptive impairment could lead to an improper body position awareness in patients with CD.

Agrin loss in Barrett's esophagus-related neoplasia and its utility as a diagnostic and predictive biomarker

PURPOSE

There is an unmet need for identifying novel biomarkers in Barrett's esophagus (BE) that could stratify patients with regards to neoplastic progression. We investigate the expression patterns of extracellular matrix (ECM) molecules in BE and BE-related neoplasia, and assess their value as biomarkers for the diagnosis of BE-related neoplasia and to predict neoplastic progression.

EXPERIMENTAL DESIGN

Gene expression analyses of ECM matrisome gene sets were performed using publicly available data on human BE, BE-related dysplasia, esophageal ADCA and normal esophagus. Immunohistochemical expression of basement membrane (BM) marker agrin (AGRN) and p53 was analyzed in biopsies of BE-related neoplasia from 321 patients in three independent cohorts.

RESULTS

Differential gene expression analysis revealed significant enrichment of ECM matrisome gene sets in dysplastic BE and ADCA compared with controls. Loss of BM AGRN expression was observed in both BE-related dysplasia and ADCA. The mean AGRN loss in BE glands was significantly higher in BErelated dysplasia and ADCA compared to non-dysplastic BE (NDBE; p<0.001; specificity=82.2% and sensitivity=96.4%). Loss of AGRN was significantly higher in NDBE samples from progressors compared to non-progressors (p<0.001) and identified patients who progressed to advanced neoplasia with a specificity of 80.2% and sensitivity of 54.8%. Moreover, the combination of AGRN loss and abnormal p53 staining identified progression to BE-related advanced neoplasia with a specificity and sensitivity of 86.5% and 58.7%.

CONCLUSIONS

We highlight ECM changes during BE progression to neoplasia. BM AGRN loss is a novel diagnostic biomarker that can identify NDBE patients at increased risk of developing advanced neoplasia.

Proteomic Profiling of the ECM of Xenograft Breast Cancer Metastases in Different Organs Reveals Distinct Metastatic Niches

Metastasis causes most cancer-related deaths, and one poorly understood aspect of metastatic cancer is the adaptability of cells from a primary tumor to create new niches and survive in multiple, different secondary sites. We used quantitative mass spectrometry to analyze the extracellular matrix (ECM), a critical component of metastatic niches, in metastases to the brain, lungs, liver, and bone marrow, all derived from parental MDA-MB-231 triple-negative breast cancer cells. Tumor and stromal cells cooperated in forming niches; stromal cells produced predominantly core, structural ECM proteins and tumor cells produced a diverse array of ECM-associated proteins, including secreted factors and modulators of the matrix. In addition, tumor and stromal cells together created distinct niches in each tissue. Downregulation of SERPINB1, a protein elevated in brain metastases, led to a reduction in brain metastasis, suggesting that some niche-specific ECM proteins may be involved in metastatic tropism. SIGNIFICANCE: Tumor and stromal cells together create distinct ECM niches in breast cancer metastases to various tissues, providing new insight into how tumor cells adapt to survive in different tissue environments.

Dual control of pcdh8l/PCNS expression and function in Xenopus laevis neural crest cells by adam13/33 via the transcription factors tfap2α and arid3a

Adam13/33 is a cell surface metalloprotease critical for cranial neural crest (CNC) cell migration. It can cleave multiple substrates including itself, fibronectin, ephrinB, cadherin-11, pcdh8 and pcdh8l (this work). Cleavage of cadherin-11 produces an extracellular fragment that promotes CNC migration. In addition, the adam13 cytoplasmic domain is cleaved by gamma secretase, translocates into the nucleus and regulates multiple genes. Here, we show that adam13 interacts with the arid3a/dril1/Bright transcription factor. This interaction promotes a proteolytic cleavage of arid3a and its translocation to the nucleus where it regulates another transcription factor: tfap2α. Tfap2α in turn activates multiple genes including the protocadherin pcdh8l (PCNS). The proteolytic activity of adam13 is critical for the release of arid3a from the plasma membrane while the cytoplasmic domain appears critical for the cleavage of arid3a. In addition to this transcriptional control of pcdh8l, adam13 cleaves pcdh8l generating an extracellular fragment that also regulates cell migration.

The Italian Dystonia Registry: rationale, design and preliminary findings

The Italian Dystonia Registry is a multicenter data collection system that will prospectively assess the phenomenology and natural history of adult-onset dystonia and will serve as a basis for future etiological, pathophysiological and therapeutic studies. In the first 6 months of activity, 20 movement disorders Italian centres have adhered to the registry and 664 patients have been recruited. Baseline historical information from this cohort provides the first general overview of adult-onset dystonia in Italy. The cohort was characterized by a lower education level than the Italian population, and most patients were employed as artisans, builders, farmers, or unskilled workers. The clinical features of our sample confirmed the peculiar characteristics of adult-onset dystonia, i.e. gender preference, peak age at onset in the sixth decade, predominance of cervical dystonia and blepharospasm over the other focal dystonias, and a tendency to spread to adjacent body parts, The sample also confirmed the association between eye symptoms and blepharospasm, whereas no clear association emerged between extracranial injury and dystonia in a body site. Adult-onset dystonia patients and the Italian population shared similar burden of arterial hypertension, type 2 diabetes, coronary heart disease, dyslipidemia, and hypothyroidism, while hyperthyroidism was more frequent in the dystonia population. Geographic stratification of the study population yielded no major difference in the most clinical and phenomenological features of dystonia. Analysis of baseline information from recruited patients indicates that the Italian Dystonia Registry may be a useful tool to capture the real world clinical practice of physicians that visit dystonia patients.

Evaluation of physical therapy in parkinsonian patients with freezing of gait: a pilot study

Objective: Freezing of gait is a frequently disabling symptom in Parkinson's disease, poorly responding to dopaminergic treatment. We investigated the short-term effectiveness of a rehabilitation protocol in parkinsonian patients with freezing of gait.

Design: Prospective, uncontrolled pilot study with open label design.

Setting: Outpatient service for rehabilitation of neurological disorders.

Subjects: Twelve patients (8 male, 4 female; aged 59-78 years; Hoehn-Yahr stage: 2-3; mean disease duration: 14.29±SD 4.1 years).

Interventions: Patients attended three (45 min) sessions every week, over a six-week period, of physical therapy focused to improve balance, postural control and walking, and to learn new strategies for overcoming freezing of gait.

Main outcome measures: Patients were evaluated before (T0), at the end (T1), and one month after (T2) rehabilitation by means of clinical rating scales (Unified Parkinson Disease Rating Scale-Motor Section; Freezing of Gait Questionnaire; Parkinson Disease Quality of Life Score) and gait parameters (number of strides, stride length and velocity) during a standardized walking test.

Results: The scores of Freezing of Gait Questionnaire and of Parkinson Disease Quality of Life Questionnaire (but not of the Unified Parkinson Disease Rating Scale-Motor Section) were significantly improved after treatment (T1). Gait parameters were significantly improved at T1 and T2.

Conclusions: We showed the potential short-term efficacy of a rehabilitative approach to freezing of gait in Parkinson's disease. The positive outcome was documented by clinical rating scales and objective gait evaluation. The rapid reversibility of the clinical benefit suggests that further studies are needed to better define the optimal frequency and duration of treatment.

Cadherin-11 localizes to focal adhesions and promotes cell-substrate adhesion

Cadherin receptors have a well-established role in cell–cell adhesion, cell polarization and differentiation. However, some cadherins also promote cell and tissue movement during embryonic development and tumour progression. In particular, cadherin-11 is upregulated during tumour and inflammatory cell invasion, but the mechanisms underlying cadherin-11 stimulated cell migration are still incompletely understood. Here, we show that cadherin-11 localizes to focal adhesions and promotes adhesion to fibronectin in Xenopus neural crest, a highly migratory embryonic cell population. Transfected cadherin-11 also localizes to focal adhesions in different mammalian cell lines, while endogenous cadherin-11 shows focal adhesion localization in primary human fibroblasts. In focal adhesions, cadherin-11 co-localizes with β1-integrin and paxillin and physically interacts with the fibronectin-binding proteoglycan syndecan-4. Adhesion to fibronectin mediated by cadherin-11/syndecan-4 complexes requires both the extracellular domain of syndecan-4, and the transmembrane and cytoplasmic domains of cadherin-11. These results reveal an unexpected role of a classical cadherin in cell–matrix adhesion during cell migration.

Cadherins are typically involved in cell-cell adhesion, however cadherin-11 promotes cell migration through an undefined mechanism. Langhe et al. show that cadherin-11 mediates adhesion to the cell matrix at focal adhesions through interaction with syndecan-4.

ADAM13 cleavage of cadherin-11 promotes CNC migration independently of the homophilic binding site

The cranial neural crest (CNC) is a highly motile population of cells that is responsible for forming the face and jaw in all vertebrates and perturbing their migration can lead to craniofacial birth defects. Cell motility requires a dynamic modification of cell-cell and cell-matrix adhesion. In the CNC, cleavage of the cell adhesion molecule cadherin-11 by ADAM13 is essential for cell migration. This cleavage generates a shed extracellular fragment of cadherin-11 (EC1-3) that possesses pro-migratory activity via an unknown mechanism. Cadherin-11 plays an important role in modulating contact inhibition of locomotion (CIL) in the CNC to regulate directional cell migration. Here, we show that while the integral cadherin-11 requires the homophilic binding site to promote CNC migration in vivo, the EC1-3 fragment does not. In addition, we show that increased ADAM13 activity or expression of the EC1-3 fragment increases CNC invasiveness in vitro and blocks the repulsive CIL response in colliding cells. This activity requires the presence of an intact homophilic binding site on the EC1-3 suggesting that the cleavage fragment may function as a competitive inhibitor of cadherin-11 adhesion in CIL but not to promote cell migration in vivo.

A randomized clinical trial to evaluate the effects of rasagiline on depressive symptoms in non-demented Parkinson's disease patients

BACKGROUND AND PURPOSE

Depressed mood is a common psychiatric problem associated with Parkinson's disease (PD), and studies have suggested a benefit of rasagiline treatment.

METHODS

ACCORDO (see the ) was a 12-week, double-blind, placebo-controlled trial to evaluate the effects of rasagiline 1 mg/day on depressive symptoms and cognition in non-demented PD patients with depressive symptoms. The primary efficacy variable was the change from baseline to week 12 in depressive symptoms measured by the Beck Depression Inventory (BDI-IA) total score. Secondary outcomes included change from baseline to week 12 in cognitive function as assessed by a comprehensive neuropsychological battery; Parkinson's disease quality of life questionnaire (PDQ-39) scores; Apathy Scale scores; and Unified Parkinson's Disease Rating Scale (UPDRS) subscores.

RESULTS

One hundred and twenty-three patients were randomized. At week 12 there was no significant difference between groups for the reduction in total BDI-IA score (primary efficacy variable). However, analysis at week 4 did show a significant difference in favour of rasagiline (marginal means difference ± SE: rasagiline -5.46 ± 0.73 vs. placebo -3.22 ± 0.67; P = 0.026). There were no significant differences between groups on any cognitive test. Rasagiline significantly improved UPDRS Parts I (P = 0.03) and II (P = 0.003) scores versus placebo at week 12. Post hoc analyses showed the statistical superiority of rasagiline versus placebo in the UPDRS Part I depression item (P = 0.04) and PDQ-39 mobility (P = 0.007) and cognition domains (P = 0.026).

CONCLUSIONS

Treatment with rasagiline did not have significant effects versus placebo on depressive symptoms or cognition in PD patients with moderate depressive symptoms. Although limited by lack of correction for multiple comparisons, post hoc analyses signalled some improvement in patient-rated cognitive and depression outcomes.

Prevalence and associated features of self-reported freezing of gait in Parkinson disease: The DEEP FOG study

Freezing of Gait (FOG) is a common and disabling symptom in patients with Parkinson disease (PD). The relationship between FOG and dopaminergic medication is complex. The aim of the present study was to estimate the prevalence of self-reported FOG, its associated clinical features, and its relationship with wearing-off in a wide PD population. This is an observational multicenter study of 634 consecutive non-demented PD patients. Patients were identified either as freezers or non-freezers based on item-3 of the Freezing of Gait-Questionnaire. FOG was then classified as on, off and onoff freezing based on its relationship with wearing-off. Patients were assessed with Unified Parkinson's Disease Rating Scale, Hoehn and Yahr scale, 8-item Parkinson's disease Questionnaire, Mini-Mental State Examination. Data from 593 patients were analyzed, 325 (54.3%) were freezers of whom 200 (61.6%) experienced FOG only during off state (off-freezers), 6 (1.8%) only during on state and 119 (36.6%) either in on and off states or independently of dopaminergic response-related symptoms (onoff-freezers). Overall, freezers vs non-freezers had longer disease duration, more advanced disease and greater disability. Moreover, freezers more frequently reported wearing-off and experienced worse quality of life. Onoff-freezers vs off-freezers were older, more severely disabled, less likely to experience wearing-off, treated with lower levodopa equivalent daily dose and with poorer cognitive performance. Self-reported FOG is mainly recognizable in advanced PD and is associated with more disability and worse quality of life. Onoff-FOG may represent the result of under-treatment or rather interpretable as a distinct clinical entity.

The Wnt receptor Frizzled-4 modulates ADAM13 metalloprotease activity

Cranial neural crest (CNC) cells are a transient population of stem cells that originate at the border of the neural plate and the epidermis, and migrate ventrally to contribute to most of the facial structures including bones, cartilage, muscles and ganglia. ADAM13 is a cell surface metalloprotease that is essential for CNC cell migration. Here, we show in Xenopus laevis embryos that the Wnt receptor Fz4 binds to the cysteine-rich domain of ADAM13 and negatively regulates its proteolytic activity in vivo. Gain of Fz4 function inhibits CNC cell migration and can be rescued by gain of ADAM13 function. Loss of Fz4 function also inhibits CNC cell migration and induces a reduction of mature ADAM13, together with an increase in the ADAM13 cytoplasmic fragment that is known to translocate into the nucleus to regulate gene expression. We propose that Fz4 associates with ADAM13 during its transport to the plasma membrane to regulate its proteolytic activity.

GSK3 and Polo-like kinase regulate ADAM13 function during cranial neural crest cell migration

ADAMs are cell surface metalloproteases that control multiple biological processes by cleaving signaling and adhesion molecules. ADAM13 controls cranial neural crest (CNC) cell migration both by cleaving cadherin-11 to release a promigratory extracellular fragment and by controlling expression of multiple genes via its cytoplasmic domain. The latter activity is regulated by γ-secretase cleavage and the translocation of the cytoplasmic domain into the nucleus. One of the genes regulated by ADAM13, the protease calpain8, is essential for CNC migration. Although the nuclear function of ADAM13 is evolutionarily conserved, it is unclear whether the transcriptional regulation is also performed by other ADAMs and how this process may be regulated. We show that ADAM13 function to promote CNC migration is regulated by two phosphorylation events involving GSK3 and Polo-like kinase (Plk). We further show that inhibition of either kinase blocks CNC migration and that the respective phosphomimetic forms of ADAM13 can rescue these inhibitions. However, these phosphorylations are not required for ADAM13 proteolysis of its substrates, γ-secretase cleavage, or nuclear translocation of its cytoplasmic domain. Of significance, migration of the CNC can be restored in the absence of Plk phosphorylation by expression of calpain-8a, pointing to impaired nuclear activity of ADAM13.

ADAM13 function is required in the 3 dimensional context of the embryo during cranial neural crest cell migration in Xenopus laevis

The cranial neural crest (CNC) is a population of cells that arises from the lateral part of the developing brain, migrates ventrally and coordinates the entire craniofacial development of vertebrates. Many molecules are involved in CNC migration including the transmembrane metalloproteases ADAM13 and 19. We have previously shown that these ADAMs cleave a number of extracellular proteins and modify the transcription of a number of genes, and that both of these activities are important for cell migration. Here we show that the knock down of ADAM13 inhibits CNC migration in vivo but not in vitro, indicating that ADAM13 function is required in the 3-dimentional context of the embryo. We further show that the migration of CNC that do not express ADAM13 and ADAM19 can be rescued in vivo by co-grafting wild type CNC. Furthermore, the migration of CNC lacking ADAM13 can be rescued by mechanically separating the CNC from the surrounding ectoderm and mesoderm. Finally, we show that ADAM13 function is autonomous to CNC tissue, as the migration of morphant CNC can only be rescued by ADAM13 expression in the CNC and not the surrounding tissues. Together our results suggest that ADAM13 changes CNC interaction with the extracellular environment and that this change is necessary for their migration in vivo.

Environmental risk factors and clinical phenotype in familial and sporadic primary blepharospasm

BACKGROUND

Although environmental and genetic factors may contribute to the etiology of blepharospasm, their relative contribution in causing familial and sporadic blepharospasm is unknown.

METHODS

First-degree relatives of 122 patients with primary blepharospasm were examined with a validated 2-step diagnostic procedure, including a screening questionnaire and examination of some relatives. Examiners were blinded to the questionnaire data for family history of probands. Data for demographic and clinical features, prior ophthalmologic complaints, and nondecaffeinated coffee intake were collected from probands before family investigation.

RESULTS

Dystonia was diagnosed in 27 relatives from 23 families (20% rate of family history for dystonia). No significant differences were found between familial and sporadic cases in the frequency of coffee drinking and eye diseases or in sex, age at onset, or tendency to spread. Multivariable conditional logistic analysis testing of 67 case patients and 127 family-matched unaffected siblings yielded a significant positive association between blepharospasm and prior eye diseases (adjusted odds ratio [OR] 2.5; 95% confidence interval [CI] 1.1-6.1; p = 0.03) and a significant inverse association between case status and ever coffee drinking (adjusted OR 0.23; 95% CI 0.1-0.8; p = 0.02).

CONCLUSIONS

The new information from this large family-based study on primary blepharospasm strongly supports eye diseases and coffee as risk factors for blepharospasm. The finding that the 2 environmental exposures exerted a similar influence on familial and sporadic blepharospasm, together with the convergent phenotypic expression in familial and sporadic cases, implies that familial and sporadic blepharospasm probably share a common etiologic background.

Mechanism of a genetically encoded dark-to-bright reporter for caspase activity

Fluorescent proteins have revolutionized modern biology with their ability to report the presence of tagged proteins in living systems. Although several fluorescent proteins have been described in which the excitation and emission properties can be modulated by external triggers, no fluorescent proteins have been described that can be activated from a silent dark state to a bright fluorescent state directly by the activity of an enzyme. We have developed a version of GFP in which fluorescence is completely quenched by appendage of a hydrophobic quenching peptide that tetramerizes GFP and prevents maturation of the chromophore. The fluorescence can be fully restored by catalytic removal of the quenching peptide, making it a robust reporter of proteolysis. We have demonstrated the utility of this uniquely dark state of GFP as a genetically encoded apoptosis reporter that monitors the function of caspases, which catalyze the fate-determining step in programmed cell death. Caspase Activatable-GFP (CA-GFP) can be activated both in vitro and in vivo, resulting in up to a 45-fold increase in fluorescent signal in bacteria and a 3-fold increase in mammalian cells. We used CA-GFP successfully to monitor real-time apoptosis in mammalian cells. This dark state of GFP may ultimately serve as a useful platform for probes of other enzymatic processes.

Translocation of the cytoplasmic domain of ADAM13 to the nucleus is essential for Calpain8-a expression and cranial neural crest cell migration

ADAMs are transmembrane metalloproteases that control cell behavior by cleaving both cell adhesion and signaling molecules. The cytoplasmic domain of ADAMs can regulate the proteolytic activity by controlling the subcellular localization and/or the activation of the protease domain. Here, we show that the cytoplasmic domain of ADAM13 is cleaved and translocates into the nucleus. Preventing this translocation renders the protein incapable of promoting cranial neural crest (CNC) cell migration in vivo, without affecting its proteolytic activity. In addition, the cytoplasmic domain of ADAM13 regulates the expression of multiple genes in CNC, including the protease Calpain8-a. Restoring the expression of Calpain8-a is sufficient to rescue CNC migration in the absence of the ADAM13 cytoplasmic domain. This study shows that the cytoplasmic domain of ADAM metalloproteases can perform essential functions in the nucleus of cells and may contribute substantially to the overall function of the protein.

Quality of sleep in primary focal dystonia: a case-control study

BACKGROUND

Sleep disturbances are common in patients with movement disorders. Evaluating quality of sleep is of primary importance because of the effect that nocturnal and daytime sleep abnormalities exert on general health status. However, quality of sleep has never been addressed in detail in patients with dystonia. The aim of this case-control study was to analyse quality of sleep in patients with the two most common forms of primary focal dystonia, blepharospasm (BSP) and cervical dystonia (CD).

METHODS

We evaluated quality of sleep (Pittsburgh Sleep Quality Index, PSQI) and excessive daytime sleepiness (Epworth Sleepiness Scale, ESS) in 98 patients with focal adult-onset dystonia (52 with BSP; 46 with CD) and in a group of 56 age-and gender-matched healthy subjects. The Beck Depression Inventory (BDI) was used for the evaluation of depressive symptomatology.

RESULTS

Quality of sleep was impaired (significantly higher PSQI scores) in both groups of patients. However, differences in PSQI scores between patients with CD and control subjects were partly confounded by BDI scores, whereas differences in PSQI scores between patients with BSP and control subjects were not influenced by BDI. Excessive daytime sleepiness was not significantly more frequent than in control subjects in either patients with BSP or patients with CD.

CONCLUSIONS

This study suggests that the assessment and treatment of insomnia-related complaints should be considered in global management plans of patients with focal dystonia, particularly in those affected by BSP.

Lower limb involvement in adult-onset primary dystonia: frequency and clinical features

BACKGROUND AND PURPOSE

Despite the growing number of reports describing adult-onset primary lower limb dystonia (LLD) this entity has never been systematically evaluated in the general population of patients with primary adult-onset dystonia.

METHODS

From outpatients with adult-onset primary dystonia attending nine Italian University centres for movement disorders we consecutively recruited 579 patients to undergo a standardized clinical evaluation.

RESULTS

Of the 579 patients assessed, 11 (1.9%) (8 women, 3 men) had LLD, either alone (n = 4, 0.7%) or as part of a segmental/multifocal dystonia (n = 7, 1.2%). The age at onset of LLD (47.9 +/- 17 years) was significantly lower than the age at onset of cranial dystonias (57.9 +/- 10.7 years for blepharospasm, and 58.9 +/- 11.8 years for oromandibular dystonia) but similar to that of all the other adult-onset primary dystonias. The lower limb was either the site of dystonia onset (36.4%) or the site of dystonia spread (63.6%). In patients in whom LLD was a site of spread, dystonia seemed to spread following a somatotopic distribution. Only one patient reported a recent trauma involving the lower limb whereas 36.4% of the patients reported pain at the site of LLD. Only 64% of our patients needed treatment for LLD, and similarly to previously reported cases, the most frequently tried treatments was botulinum toxin and trihexyphenidyl.

CONCLUSION

The lower limb is an uncommon but possible topographical site of dystonia in adulthood that should be kept in consideration during clinical evaluation.

The rationale for motor learning in Parkinson's disease

Parkinson's disease (PD) is a chronic progressive disorder mainly affecting the motor system. PD is only partially controlled by symptomatic dopaminergic treatment. Therefore, motor rehabilitation can be used in PD to reduce complications and to train patients in the use of compensatory movement strategies. Rehabilitative practice is largely dependent on the efficiency of motor learning, i.e. the acquisition of new abilities or the adaptation of pre-existing ones. Although patients with PD are able to improve their motor performance through practice, the amount and persistence of clinical benefit are uncertain. Both ''implicit'' (procedural) and ''explicit'' (declarative) features of motor learning have been extensively investigated in patients with PD using neuropsychological testing, serial reaction time paradigms, and analysis of reaching movements. Evidence from these studies suggests an early impairment of ''explicit'' learning in PD, while ''implicit'' learning is relatively preserved. The consolidation of learned motor tasks is defective in PD and the mechanisms of motor learning seem to be independent from dopamine-replacement therapy. The knowledge of motor learning in PD is critical in designing more effective rehabilitative protocols.

Brain-derived neurotrophic factor and risk for primary adult-onset cranial-cervical dystonia

BACKGROUND AND PURPOSE

Adult-onset dystonia may be related, amongst other factors, to abnormal neuronal plasticity in cortical and subcortical structures. Brain-derived neurotrophic factor is a major modulator of synaptic efficiency and neuronal plasticity. Recent works documented that a single nucleotide polymorphism (SNP) of the BDNF gene, the Val66Met SNP, modulates short-term plastic changes within motor cortical circuits. In this study we aimed at exploring the effect of this SNP upon the risk of developing common forms of primary adult-onset dystonia.

METHODS

We explored the influence of the Val66Met SNP of the BDNF gene on the risk of cranial and cervical dystonia in a cohort of 156 Italian patients and 170 age- and gender-matched healthy control subjects drawn from the same population.

RESULTS

The presence of the rare Met allele was not significantly associated with the diagnosis of dystonia (age- and gender-adjusted odds ratios of 1.22, P = 0.38). The study had a >90% power to detect a 50% change in the risk of developing cranial-cervical dystonia associated with the presence of the Met allele. Moreover, there was no relationship between Val66Met SNP and age at dystonia onset or type of dystonia.

CONCLUSION

Our data do not support the common variant Val66Met of the BDNF gene as an etiologic factor shared by the various forms of primary adult-onset dystonia.

Neurophysiological effects of botulinum toxin type a

Botulinum toxin type A (BoNT-A) acts peripherally by inhibiting acetylcholine release from the presynaptic neuromuscular terminals, thus weakening muscle contraction, and its clinical benefit depends primarily on the toxin's peripheral action. In addition to acting directly at the neuromuscular junction, the toxin alters sensory inputs to the central nervous system, thus indirectly inducing secondary central changes. Some of the long-term clinical benefits of BoNT-A treatment may also reflect plastic changes in motor output after the reorganization of synaptic density.

Long-term assessment of the risk of spread in primary late-onset focal dystonia

BACKGROUND

Primary late-onset focal dystonias may spread over time to adjacent body regions, but differences in the risk of spread over time among the various focal forms and the influence of age at dystonia onset on the risk of spread are not well established.

METHODS

Patients presenting with primary late-onset focal blepharospasm (BSP, n = 124), cervical dystonia (CD, n = 73) and focal hand dystonia (FHD, n = 24) with 10 years or more of disease duration (mean +/- SD, 15.3 (SD 4.9) years) were included in the study. The relationship between demographic/clinical variables and spread of dystonia was assessed by Kaplan-Meier survival curves and Cox proportional hazard regression models.

RESULTS

Patients starting with BSP, CD and FHD had similar age, sex and disease duration. Age at dystonia onset, age at initial spread and the risk of initial spread were significantly higher, whereas time elapsing from onset to initial spread was significantly lower in the BSP group than in those with onset in the neck or in the upper extremities. Conversely, these parameters were similar in the CD and FHD groups. The greater risk of spread in the BSP group was mainly evident in the first 5 years of history; thereafter, it declined and became similar to that of patients with CD/FHD. The difference in the risk of initial spread by site of onset was partly confounded by age at dystonia onset. Site of and age at dystonia onset, and age at first spread, were not significant predictors of the risk of a second spread.

CONCLUSION

This study adds new insights into the phenomenon of spread of primary late-onset focal dystonia and provides the framework for future studies aimed at an indepth investigation of the mechanism(s) of spread.

Intrafusal effects of botulinum toxin in post-stroke upper limb spasticity

A previous study in subjects with focal dystonia suggested that the greater and longer-lasting effect induced by botulinum toxin type A (BoNT-A) on the tonic vibration reflex (TVR) than on the maximal M-wave (M-max) might be the physiological marker of the toxin's action at the level of intrafusal muscle fibres. With this approach, we investigated the possible effect of BoNT-A on fusimotor synapses in eight patients with post-stroke spasticity (four with no residual motor capacity before treatment and four with partially spared muscle strength and residual motor capacity). TVR and M-max were recorded from the wrist and finger flexor muscles before treatment and at 1, 4 and 7 months afterwards. The TVR reduction was greater than the M-max reduction and remained fairly constant over time only in the subjects with a residual motor capacity before the treatment. This pilot study suggests that some degree of strength and active movement is necessary for the action of BoNT-A on intrafusal fibres.

Influence of coffee drinking and cigarette smoking on the risk of primary late onset blepharospasm: evidence from a multicentre case control study

Prior coffee and smoking habits were investigated in a multicentre case control study involving 166 patients presenting with primary late onset blepharospasm (BSP), 228 hospital control patients with primary hemifacial spasm and 187 population control subjects from five Italian centres. Information on age at disease onset, smoking and coffee drinking status at the reference age and average number of cups of coffee drunk/cigarettes smoked per day reached high and similar test-retest reproducibility in case and control patients. Unadjusted logistic regression analysis yielded a significant inverse association of prior coffee drinking and cigarette smoking with case status for the control groups. After adjustment for age, sex, referral centre, disease duration, years of schooling and ever coffee drinking/cigarette smoking, as appropriate, the smoking estimate lacked significance whereas the association of coffee intake and BSP did not (cases vs hospital control patients: OR 0.37 (95% CI 0.20 to 0.67); cases vs population control subjects: OR 0.44 (95% CI 0.23 to 0.85)). The strength of the inverse association between BSP and coffee intake tended to increase with the average number of cups drunk per day. There was a significant correlation between age of BSP onset and number of cups per day (adjusted regression coefficient 1.73; p = 0.001) whereas no correlation was found with number of packs of cigarettes per day. Coffee drinking may be inversely associated with the development of primary BSP and this association may partly depend on the amount consumed.

ATP13A2 missense mutations in juvenile parkinsonism and young onset Parkinson disease

OBJECTIVE

To assess the prevalence, nature, and associated phenotypes of ATP13A2 gene mutations among patients with juvenile parkinsonism (onset <21 years) or young onset (between 21 and 40 years) Parkinson disease (YOPD).

METHODS

We studied 46 patients, mostly from Italy or Brazil, including 11 with juvenile parkinsonism and 35 with YOPD. Thirty-three cases were sporadic and 13 had positive family history compatible with autosomal recessive inheritance. Forty-two had only parkinsonian signs, while four (all juvenile-onset) had multisystemic involvement. The whole ATP13A2 coding region (29 exons) and exon-intron boundaries were sequenced from genomic DNA.

RESULTS

A novel homozygous missense mutation (Gly504Arg) was identified in one sporadic case from Brazil with juvenile parkinsonism. This patient had symptoms onset at age 12, levodopa-responsive severe akinetic-rigid parkinsonism, levodopa-induced motor fluctuations and dyskinesias, severe visual hallucinations, and supranuclear vertical gaze paresis, but no pyramidal deficit nor dementia. Brain CT scan showed moderate diffuse atrophy. Furthermore, two Italian cases with YOPD without atypical features carried a novel missense mutation (Thr12Met, Gly533Arg) in single heterozygous state.

CONCLUSIONS

We confirm that ATP13A2 homozygous mutations are associated with human parkinsonism, and expand the associated genotypic and clinical spectrum, by describing a homozygous missense mutation in this gene in a patient with a phenotype milder than that initially associated with ATP13A2 mutations (Kufor-Rakeb syndrome). Our data also suggest that ATP13A2 single heterozygous mutations might be etiologically relevant for patients with YOPD and further studies of this gene in Parkinson disease are warranted.

The postural disorientation induced by neck muscle vibration subsides on lightly touching a stationary surface or aiming at it

The aim of this study was to investigate whether the standing body spatial disorientation, induced by neck muscle vibration, and the related post-effects can be suppressed by light finger touch (LFT) of a stationary surface. Continuous (60 s) vibration of dorsal neck or sternocleidomastoid muscle was administered with eyes closed. The center of foot pressure (CFP) displacement, measured by a stabilometric platform, indicated the degree of vibration-induced body tilt. We also investigated whether sensory information from LFT itself was necessary or anticipation of a more secure posture was enough for reducing vibration effects. To this aim, we administered a vibration pulse (5 s) to dorsal neck or sternocleidomastoid muscle and during reaching to the stationary surface. CFP was recorded during both vibration and post-vibration condition and during the aiming task. Neck vibration induced significant CFP displacement in the direction opposite to vibration site. Post-vibration, CFP slowly returned to control values with ample oscillations. LFT during vibration reduced body tilt. LFT was more effective when fingertip contact was in the plane of the greatest tilt. LFT applied during either vibration or post-vibration period reduced post-vibration effects. Reaching toward the stationary surface was enough for reducing vibration-induced body tilt to values close to those observed during actual LFT. The novel conclusions of this study are: 1) LFT is able to relieve the effects of vibration-induced abnormal proprioceptive input from the neck, a segment central to postural control and orientation; 2) LFT during vibration also attenuates vibration post-effects, further suggesting that its action is not merely mechanical; 3) the intention to stabilize the body generates a new postural 'set' sufficient for diminishing body tilt.

Creutzfeldt-Jakob disease presenting as corticobasal degeneration: a neurophysiological study

Creutzfeldt-Jakob disease (CJD) can occasionally present with a clinical picture resembling a corticobasal degeneration (CBD). Transcallosal inhibition, as tested by focal transcranial magnetic stimulation, is frequently absent or highly disrupted in CBD patients. We report a case of CJD presenting at the beginning of the disease as a CBD in which the ipsilateral silent period (iSP) was present and well detectable. This brief report shows that study of the iSP may be a useful diagnostic tool in order to differentiate CBD from syndromes presenting with similar clinical features.

Early-onset parkinsonism associated with PINK1 mutations: frequency, genotypes, and phenotypes

OBJECTIVE

To assess the prevalence, nature, and associated phenotypes of PINK1 gene mutations in a large series of patients with early-onset (<50 years) parkinsonism.

METHODS

The authors studied 134 patients (116 sporadic and 18 familial; 77% Italian) and 90 Italian controls. The whole PINK1 coding region was sequenced from genomic DNA; cDNA was analyzed in selected cases.

RESULTS

Homozygous pathogenic mutations were identified in 4 of 90 Italian sporadic cases, including the novel Gln456Stop mutation; single heterozygous truncating or missense mutations were found in another 4 Italian sporadic cases, including two novel mutations, Pro196Leu and Gln456Stop. Pathogenic mutations were not identified in the familial cases. Novel (Gln115Leu) and known polymorphisms were identified with similar frequency in cases and controls. In cases carrying single heterozygous mutation, cDNA analysis detected no additional mutations, and revealed a major pathogenic effect at mRNA level for the mutant C1366T/Gln456Stop allele. All patients with homozygous mutations had very early disease onset, slow progression, and excellent response to l-dopa, including, in some, symmetric onset, dystonia at onset, and sleep benefit, resembling parkin-related disease. Phenotype in patients with single heterozygous mutation was similar, but onset was later.

CONCLUSIONS

PINK1 homozygous mutations are a relevant cause of disease among Italian sporadic patients with early-onset parkinsonism. The role of mutations found in single heterozygous state is difficult to interpret. Our study suggests that, at least in some patients, these mutations are disease causing, in combination with additional, still unknown factors.

A family study on primary blepharospasm

BACKGROUND

Previous family studies provided evidence that blepharospasm (BSP) can aggregate in families but did not give accurate and reliable information on the characteristics and degree of familial clustering.

AIM

To evaluate the proportion of familial and non-familial BSP cases, the clinical expression of dystonia within families, the inheritance pattern, and the extent of penetrance.

METHODS

The study was based on the examination of the first degree relatives of 56 probands with primary BSP.

RESULTS

The 56 families produced a potential population of 436 first degree relatives of whom 296 were alive and 233 were examined. The proportion of index patients with at least one first degree relative affected by BSP, or adult onset dystonia other than BSP, was 27%. There was a remarkable degree of phenotypic variability of dystonia within families. Similar segregation ratios were calculated for probands' siblings and children. Under the assumption of autosomal dominant transmission of adult onset dystonia, penetrance was about 20%.

CONCLUSIONS

The findings of this family study are relevant for accurately counselling the families of patients with BSP and may help identify the most appropriate study design to explore genetic susceptibility in BSP.

REM sleep behaviour disorder in Parkinson's disease: a questionnaire-based study

The aim of the study was to determine the clinical frequency and features of REM sleep behaviour disorder (RBD) in a large population of Parkinson's disease (PD) patients using defined diagnostic criteria both for RBD and PD. Six trained neurologists used a semistructured questionnaire based on ICSD-R diagnostic criteria for RBD to evaluate 200 PD patients and their caregivers. Interobserver reliability for the diagnosis of RBD was "substantial" (Kappa 0.65). Five patients were excluded from the study because of an MMSE lower than 25. The demographic and PD clinical features were compared in the clinically defined RBD group and in those without RBD (NRBD). Then the RBD features during the last year were analysed in the affected group. Out of 195 patients, 66 fulfilled the ICSD-R criteria for RBD; 62 patients reported RBD during the last year (frequency 31.8%). RBD features: two or more episodes per week in 35.5%; upper limb movements in 87%; lower limb movements in 79%; vocalisations during events in 85%. RBD onset was before PD in 27% of patients; 69% of the RBD group had injured themselves or their caregivers during sleep. According to multivariate analysis, RBD was associated with male gender, age and PD duration. Brief training and the use of a semistructured questionnaire may help the neurologist in dealing with sleep disturbances in PD patients. The search for RBD symptoms in PD is highly recommended, especially in patients with a long disease duration, the risk of sleep-related injuries being high.

Impairment of transcallosal inhibition in patients with corticobasal degeneration

OBJECTIVE

To evaluate the motor function of the transcallosal pathways in patients with clinical diagnosis of corticobasal degeneration (CBD).

METHODS

In a group of 7 patients (4 males, 3 females; mean age 70.6 years) with clinical diagnosis of probable CBD (and in 8 age-matched normal controls) we evaluated the suppression of the ongoing voluntary EMG activity in the opponens pollicis muscle induced by focal transcranial magnetic stimulation (TMS) of the ipsilateral hand motor cortex. Such ipsilateral silent period (iSP) is mediated from one motor cortex to the contralateral side via a transcallosal pathway. In addition, CBD patients were investigated with magnetic resonance imaging (MRI) and neuropsychological assessment.

RESULTS

iSP was normal in 4 CBD patients, while it was bilaterally disrupted in the other 3. MRI showed an atrophy of the corpus callosum (middle-posterior part of the trunk) in the CBD patients with iSP disruption. Neuropsychological evaluation showed in patients with iSP impairment a decrease of verbal fluencies associated with an impairment of attentive function.

CONCLUSIONS

A proportion of CBD patients shows physiological evidence of impaired callosal motor function and atrophy of the corpus callosum on MRI, possibly correlated to dysphasic and cognitive disorders.

Role of the dopamine D5 receptor (DRD5) as a susceptibility gene for cervical dystonia

Cervical dystonia (CD) is one of the most common forms of primary dystonia. The pathogenesis of the disease is still unknown, although evidence suggests a role for genetic factors. Recently, a polymorphism in the dopamine D5 receptor (DRD5) gene has been associated with the disease in a British population, suggesting that DRD5 is a susceptibility gene for CD. To confirm these data, we performed a case-control study of the microsatellite (CT/GT/GA)(n) at the DRD5 locus in 104 Italian CD patients and 104 healthy controls. The frequency of allele 4 was higher in the CD patients compared to the controls. This resulted in a twofold increased risk of developing the disease. These results provide further evidence of an association between DRD5 and cervical dystonia, supporting the involvement of the dopamine pathway in the pathogenesis of CD.