To assess the impact of the new botulinum neurotoxin type A preparation NT 201 (Xeomin; Merz Pharmaceuticals GmbH, Frankfurt, Germany) on muscle tone, functional disability, and caregiver burden in patients with poststroke upper limb spasticity in a randomized, placebo-controlled, double-blind study. One hundred forty-eight patients with an Ashworth Scale score of 2 or higher for wrist and finger flexors and at least moderate disability in their principal therapeutic target of the Disability Assessment Scale were treated either with NT 201 (median, 320 U) or placebo and followed up for up to 20 weeks. Treatment of the wrist and finger muscles was mandatory. A significantly higher proportion of patients treated with NT 201 were responders (improvement of > or =1 point in the Ashworth Scale score), as observed in comparison to placebo 4 weeks after treatment in wrist flexors (odds ratio, 3.97; 95% confidence interval, 1.9-8.3; P < 0.001, intent to treat). For all treated flexor muscle groups, statistically significant odds ratios in favor of NT 201 were observed at week 4 (P < or = 0.009). Statistically significant results in favor of NT 201 were observed at all postinjection visits until week 12 in the principal therapeutic target (P < or = 0.005), in the global assessment of efficacy (P < 0.001), and in some tasks of the Carer Burden Scale (P < 0.05). Similar numbers of patients in each group experienced at least 1 adverse event (NT 201, n = 21; placebo, n = 20). Importantly, none of the patients developed neutralizing antibodies. NT 201 led to statistically significant improvements in muscle tone and disability and was well tolerated in patients with poststroke upper limb spasticity.
The understanding of neurodegenerative diseases, traditionally considered to be well-defined entities with distinguishable clinical phenotypes, has undergone a major shift over the last 20 years. The diagnosis of neurodegenerative diseases primarily requires functional brain imaging techniques or invasive tests such as lumbar puncture to assess cerebrospinal fluid. A new biological approach and research efforts, especially in vivo, have focused on biomarkers indicating underlying proteinopathy in cerebrospinal fluid and blood serum. However, due to the complexity and heterogeneity of neurodegenerative processes within the central nervous system and the large number of overlapping clinical diagnoses, identifying individual proteinopathies is relatively difficult and often not entirely accurate. For this reason, there is an urgent need to develop laboratory methods for identifying specific biomarkers, understand the molecular basis of neurodegenerative disorders and classify the quantifiable and readily available tools that can accelerate efforts to translate the knowledge into disease-modifying therapies that can improve and simplify the areas of differential diagnosis, as well as monitor the disease course with the aim of estimating the prognosis or evaluating the effects of treatment. The aim of this review is to summarize the current knowledge about clinically relevant biomarkers in different neurodegenerative diseases.
The current nosological concept of α-synucleinopathies characterized by the presence of Lewy bodies (LBs) includes Parkinson’s disease (PD), Parkinson’s disease dementia (PDD), and dementia with Lewy bodies (DLB), for which the term “Lewy body disease” (LBD) has recently been proposed due to their considerable clinical and pathological overlap. However, even this term does not seem to describe the true nature of this group of diseases. The subsequent discoveries of α-synuclein (αSyn), SNCA gene, and the introduction of new immunohistochemical methods have started intensive research into the molecular-biological aspects of these diseases. In light of today’s knowledge, the role of LBs in the pathogenesis and classification of these nosological entities remains somewhat uncertain. An increasingly more important role is attributed to other factors as the presence of various LBs precursors, post-translational αSyn modifications, various αSyn strains, the deposition of other pathological proteins (particularly β-amyloid), and the discovery of selective vulnerability of specific cells due to anatomical configuration or synaptic dysfunction. Resulting genetic inputs can undoubtedly be considered as the main essence of these factors. Molecular–genetic data indicate that not only in PD but also in DLB, a unique genetic architecture can be ascertained, predisposing to the development of specific disease phenotypes. The presence of LBs thus remains only a kind of link between these disorders, and the term “diseases with Lewy bodies” therefore results somewhat more accurate.
In dystonic and spastic movement disorders, however different in their pathophysiological mechanisms, a similar impairment of sensorimotor control with special emphasis on afferentation is assumed. Peripheral intervention on afferent inputs evokes plastic changes within the central sensorimotor system. Intramuscular application of botulinum toxin type A (BoNT-A) is a standard evidence-based treatment for both conditions. Apart from its peripheral action on muscle spindles, a growing body of evidence suggests that BoNT-A effects could also be mediated by changes at the central level including cerebral cortex. We review recent studies employing electrophysiology and neuroimaging to investigate how intramuscular application of BoNT-A influences cortical reorganization. Based on such data, BoNT-A becomes gradually accepted as a promising tool to correct the maladaptive plastic changes within the sensorimotor cortex. In summary, electrophysiology and especially neuroimaging studies with BoNT-A further our understanding of pathophysiology underlying dystonic and spastic movement disorders and may consequently help develop novel treatment strategies based on neural plasticity.
8 May 2009 in Developmental Medicine & Child Neurology