To define numerically the clinical severity of facioscapulohumeral muscular dystrophy (FSHD), we developed a protocol that quantifies muscle weakness by combining the functional evaluation of six muscle groups affected in this disease. To validate reproducibility of the protocol, 69 patients were recruited. Each patient was evaluated by at least five neurologists, and an FSHD severity score was given by each examiner. The degree of agreement among clinicians' evaluations was measured by kappa-statistics. Nineteen subjects received a score between 0 and 1, 9 had a score between 2 and 4, 20 received a score between 5 and 10, and 8 had a score between 11 and 15. Of the 13 subjects with D4Z4 alleles within the normal range (ranging from 10 to 150 repeats), 12 obtained a score of 0 and only 1 had a score of 1. Kappa-statistics showed a very high concordance for all muscle groups. We developed a simple, reliable, easily used tool to define the clinical expression of FSHD. Longitudinal studies will assess its sensitivity and utility in measuring changes for widespread use.

BackgroundFacioscapulohumeral muscular dystrophy (FSHD) is one of the most common muscular dystrophies and is characterized by a non-conventional genetic mechanism activated by pathogenic D4Z4 repeat contractions. By muscle Magnetic Resonance Imaging (MRI) we observed that T2-short tau inversion recovery (T2-STIR) sequences identify two different conditions in which each muscle can be found before the irreversible dystrophic alteration, marked as T1-weighted sequence hyperintensity, takes place. We studied these conditions in order to obtain further information on the molecular mechanisms involved in the selective wasting of single muscles or muscle groups in this disease.MethodsHistopathology, gene expression profiling and real time PCR were performed on biopsies from FSHD muscles with different MRI pattern (T1-weighted normal/T2-STIR normal and T1-weighted normal/T2-STIR hyperintense). Data were compared with those from inflammatory myopathies, dysferlinopathies and normal controls. In order to validate obtained results, two additional FSHD samples with different MRI pattern were analyzed.ResultsMyopathic and inflammatory changes characterized T2-STIR hyperintense FSHD muscles, at variance with T2-STIR normal muscles. These two states could be easily distinguished from each other by their transcriptional profile. The comparison between T2-STIR hyperintense FSHD muscles and inflammatory myopathy muscles showed peculiar changes, although many alterations were shared among these conditions.ConclusionsAt the single muscle level, different stages of the disease correspond to the two MRI patterns. T2-STIR hyperintense FSHD muscles are more similar to inflammatory myopathies than to T2-STIR normal FSHD muscles or other muscular dystrophies, and share with them upregulation of genes involved in innate and adaptive immunity. Our data suggest that selective inflammation, together with perturbation in biological processes such as neoangiogenesis, lipid metabolism and adipokine production, may contribute to the sequential bursts of muscle degeneration that involve individual muscles in an asynchronous manner in this disease.

Facioscapulohumeral muscular dystrophy (FSHD) is an inherited disease, and although strongly suggested, a contribution of inflammation to its pathogenesis has never been demonstrated. In FSHD patients, we found by immunohistochemistry inflammatory infiltrates mainly composed by CD8(+) T cells in muscles showing hyperintensity features on T2-weighted short tau inversion recovery magnetic resonance imaging (T2-STIR-MRI) sequences. Therefore, we evaluated the presence of circulating activated immune cells and the production of cytokines in patients with or without muscles showing hyperintensity features on T2-STIR-MRI sequences and from controls. FSHD patients displaying hyperintensity features in one or more muscles showed higher CD8(+)pSTAT1(+), CD8(+)T-bet(+) T cells and CD14(+)pSTAT1(+), CD14(+)T-bet(+) cells percentages and IL12p40, IFNγ and TNFα levels than patients without muscles displaying hyperintense features and controls. Moreover, the percentages of CD8(+)pSTAT1(+), CD8(+)T-bet(+) and CD14(+)pSTAT1(+) cells correlated with the proportion of muscles displaying hyperintensity features at T2-STIR sequences. These data indicate that circulating activated immune cells, mainly CD8(+) T cells, may favour FSHD progression by promoting active phases of muscle inflammation.

The dynamics of the resting brain exhibit transitions between a small number of discrete networks, each remaining stable for tens to hundreds of milliseconds. These functional microstates are thought to be the building blocks of spontaneous consciousness. The electroencephalogram (EEG) is a useful tool for imaging microstates, and EEG microstate analysis can potentially give insight into altered brain dynamics underpinning cognitive impairment in disorders such as Alzheimer’s disease (AD). Since EEG is non-invasive and relatively inexpensive, EEG microstates have the potential to be useful clinical tools for aiding early diagnosis of AD. In this study, EEG was collected from two independent cohorts of probable AD and cognitively healthy control participants, and a cohort of mild cognitive impairment (MCI) patients with four-year clinical follow-up. The microstate associated with the frontoparietal working-memory/attention network was altered in AD due to parietal inactivation. Using a novel measure of complexity, we found microstate transitioning was slower and less complex in AD. When combined with a spectral EEG measure, microstate complexity could classify AD with sensitivity and specificity > 80%, which was tested on an independent cohort, and could predict progression from MCI to AD in a small preliminary test cohort of 11 participants. EEG microstates therefore have potential to be a non-invasive functional biomarker of AD.

Our large-scale cross-sectional data provide preliminary evidence for the usefulness of MRI in clinical trials, and set the baseline for longitudinal studies. Muscle MRI can also be used for distinguishing facioscapulohumeral muscular dystrophy from other myopathies in selected cases. Finally, our results are consistent with a model that configures facioscapulohumeral muscular dystrophy as a "muscle-by-muscle" disease. Ann Neurol 2016;79:854-864.