Multifocal motor neuropathy as a mimic of amyotrophic lateral sclerosis: Serum neurofilament light chain as a reliable diagnostic biomarker.

INTRODUCTION/AIMS: The clinical presentation of multifocal motor neuropathy (MMN) may mimic early amyotrophic lateral sclerosis (ALS) with predominant lower motor neuron (LMN) involvement, posing a diagnostic challenge. Both diseases have specific treatments and prognoses, highlighting the importance of early diagnosis. The aim of this study was to assess the diagnostic value of serum neurofilament light chain (NfL) in differentiating MMN from LMN dominant ALS. METHODS: NfL was measured in serum in n = 37 patients with MMN and n = 37 age- and sex-matched patients with LMN dominant ALS, to determine the diagnostic accuracy. Clinical and demographic data were obtained at the time of NfL sampling. RESULTS: Serum NfL concentration was significantly lower in MMN patients compared to ALS patients (mean 20.7 pg/mL vs. 59.4 pg/mL, p < .01). NfL demonstrated good diagnostic value in discriminating the two groups (AUC 0.985 [95% CI 0.963-1.000], sensitivity 94.6%, specificity 100%, cut-off 44.00 pg/mL). DISCUSSION: NfL could be a helpful tool in differentiating MMN from LMN dominant ALS in those patients in whom electrophysiological and clinical examinations remain inconclusive early in the diagnostic process.

Muscle MRI in Patients With Oculopharyngeal Muscular Dystrophy: A Longitudinal Study

BACKGROUND AND OBJECTIVES: Oculopharyngeal muscular dystrophy (OPMD) is a rare progressive neuromuscular disease. MRI is one of the techniques that is used in neuromuscular disorders to evaluate muscle alterations. The aim of this study was to describe the pattern of fatty infiltration of orofacial and leg muscles using quantitative muscle MRI in a large national cohort and to determine whether MRI can be used as an imaging biomarker of disease progression in OPMD. METHODS: Patients with OPMD (18 years or older) were invited from the national neuromuscular database or by their treating physicians and were examined twice with an interval of 20 months, with quantitative MRI of orofacial and leg muscles to assess fatty infiltration which were compared with clinical measures. RESULTS: In 43 patients with genetically confirmed OPMD, the muscles that were affected most severely were the tongue (mean fat fraction: 37.0%, SD 16.6), adductor magnus (31.9%; 27.1), and soleus (27.9%; 21.5) muscles. The rectus femoris and tibialis anterior muscles were least severely affected (mean fat fractions: 6.8%; SD 4.7, 7.5%; 5.9). Eleven of 14 significant correlations were found between fat fraction and a clinical task in the corresponding muscles (r = -0.312 to -0.769, CI = -0.874 to -0.005). At follow-up, fat fractions had increased significantly in 17 of the 26 muscles: mean 1.7% in the upper leg muscles (CI = 0.8-2.4), 1.7% (1.0-2.3) in the lower leg muscles, and 1.9% (0.6-3.3) in the orofacial muscles (p < 0.05). The largest increase was seen for the soleus (3.8%, CI = 2.5-5.1). Correlations were found between disease duration and repeat length vs increased fat fraction in 7 leg muscles (r = 0.323 to -0.412, p < 0.05). DISCUSSION: According to quantitative muscle MRI, the tongue, adductor magnus and soleus show the largest fat infiltration levels in patients with OPMD. Fat fractions increased in several orofacial and leg muscles over 20 months, with the largest fat fraction increase seen in the soleus. This study supports that this technique is sensitive enough to show worsening in fat fractions of orofacial and leg muscles and therefore a responsive biomarker for future clinical trials.

Role of respiratory characteristics in treatment adherence with noninvasive home mechanical ventilation in myotonic dystrophy type 1, a retrospective study.

Chronic respiratory insufficiency is common in patients with myotonic dystrophy type 1 (DM1) and can be treated with noninvasive home mechanical ventilation (HMV). HMV is not always tolerated well resulting in low treatment adherence. We aimed to analyze if baseline respiratory characteristics such as pulmonary function, level of pCO2 and presence of sleep apnea are associated with HMV treatment adherence in DM1 patients. Pulmonary function testing, polysomnography and blood gas measurement data of DM1 patients were retrospectively collected. Initiation of HMV and treatment adherence after one year was documented. Patients with low treatment adherence (average daily use of HMV <5 h) were grouped with patients that discontinued HMV and compared with patients with high treatment adherence (average daily use of HMV >5 h). HMV was initiated in 101 patients. After one year, 58 patients had low treatment adherence. There were no differences between the low and high treatment adherence group regarding the respiratory characteristics. None of the included predictors (gender, age, body mass index, cytosine-thymine-guanine repeat length, FVC, daytime pCO2, bicarbonate, nighttime pCO2, nighttime base excess, apnea-hypopnea index and mean saturation during sleep) was able to significantly predict high treatment adherence. In conclusion, the respiratory characteristics are not associated with treatment adherence with HMV in DM1 patients and cannot be used to identify patients at risk for low HMV treatment adherence.

Transcranial Magnetic Stimulation in the Differential Diagnosis of Unilateral Peripheral Facial Nerve Palsy.

(1) Background: This study aims to assess the diagnostic accuracy of parameters based on a combination of transcranial magnetic stimulation (TMS) and electrical stimulation (ES) in the differentiation between idiopathic and secondary facial palsy in a large cohort of patients. (2) Methods: Patients with unilateral facial palsy ≤7 days after symptom onset were included. Compound muscle action potential (CMAP) amplitudes were measured after stimulation of both facial nerves at (A) the internal acoustic meatus using TMS, CMAP-TMS, and (B) at the stylomastoid foramen using electrical stimulation, CMAP-ES. To express the degree of nerve dysfunction in the facial canal specifically, the amplitude reduction of the CMAP-TMS in relation to CMAP-ES was calculated and expressed as a percentage (amplitude reduction over the facial canal, ARFC). Receiver Operating Characteristic (ROC) curves were constructed to assess the diagnostic accuracy of ARFC as a marker to discriminate between patients with idiopathic and secondary facial palsy. (3) Results: Data from 498 patient records were analyzed. Idiopathic facial palsy was diagnosed in 424 patients, and secondary facial palsy in 74 patients. The area under the ROC curve for ARFC was 0.398. (4) Conclusions: The overall diagnostic accuracy of this method to differentiate secondary from idiopathic facial palsy is low.

Differentiation of Critical Illness Myopathy and Critical Illness Neuropathy Using Nerve Ultrasonography.

PURPOSE: Intensive care unit-acquired weakness occurs frequently in intensive care unit patients, including critical illness myopathy (CIM) and critical illness polyneuropathy (CIPN). The authors present a prospective study to assess the ultrasound pattern sum score to differentiate between confirmed CIM, sensory neuropathy, and CIPN cases. METHODS: Cross-sectional areas of 12 predefined nerve segments in 16 patients were sonographically examined. Single-nerve cross-sectional areas and ultrasound pattern sum score values were compared; results are given as P -values and receiver operating characteristic area under the curve (AUC). RESULTS: In neuropathy, significant single-nerve cross-sectional area enlargement was observed in the median ( P = 0.04), ulnar ( P = 0.04), and fibular nerves ( P = 0.0003). The ultrasound pattern sum score could reliably differentiate between pure CIM and neuropathy ( P = 0.0002, AUC 0.92), CIM and sensory neuropathy ( P = 0.001, AUC 0.88), and CIM and CIPN ( P = 0.007, AUC 0.92), but not between sensory neuropathy and CIPN ( P = 0.599, AUC 0.48). CONCLUSIONS: Nerve ultrasonography reliably identifies neuropathy in intensive care unit-acquired weakness, yet cannot differentiate between sensory neuropathy and CIPN. A standardized ultrasound algorithm can serve as a fast bedside test for the presence of neuropathy in intensive care unit-acquired weakness.

An evaluation of 24 h Holter monitoring in patients with myotonic dystrophy type 1.

AIMS: To evaluate the clinical effectiveness of routine 24 h Holter monitoring to screen for conduction disturbances and arrhythmias in patients with myotonic dystrophy type 1 (DM1). METHODS AND RESULTS: A retrospective two-centre study was conducted including DM1-affected individuals undergoing routine cardiac screening with at least one 24 h Holter monitoring between January 2010 and December 2020. For each individual, the following data were collected: Holter results, results of electrocardiograms (ECGs) performed at the same year as Holter monitoring, presence of cardiac complaints, and neuromuscular status. Holter findings were compared with the results of cardiac screening (ECG + history taking) performed at the same year. Cardiac conduction abnormalities and/or arrhythmias that would have remained undiagnosed based on history taking and ECG alone were considered de novo findings. A total 235 genetically confirmed DM1 patients were included. Abnormal Holter results were discovered in 126 (54%) patients after a mean follow-up of 64 ± 28 months in which an average of 3 ± 1 Holter recordings per patient was performed. Abnormalities upon Holter mainly consisted of conduction disorders (70%) such as atrioventricular (AV) block. Out of 126 patients with abnormal Holter findings, 74 (59%) patients had de novo Holter findings including second-degree AV block, atrial fibrillation/flutter and non-sustained ventricular tachycardia. Patient characteristics were unable to predict the occurrence of de novo Holter findings. In 39 out of 133 (29%) patients with normal ECGs upon yearly cardiac screening, abnormalities were found on Holter monitoring during follow-up. CONCLUSION: Twenty-four hour Holter monitoring is of added value to routine cardiac screening for all DM1 patients.

Myotonic dystrophy type 1: A comparison between the adult- and late-onset subtype.

INTRODUCTION/AIMS: Although the extent of muscle weakness and organ complications has not been well studied in patients with late-onset myotonic dystrophy type 1 (DM1), adult-onset DM1 is associated with severe muscle involvement and possible life-threatening cardiac and respiratory complications. In this study we aimed to compare the clinical phenotype of adult-onset vs late-onset DM1, focusing on the prevalence of cardiac, respiratory, and muscular involvement. METHODS: Data were prospectively collected in the Dutch DM1 registry. RESULTS: Two hundred seventy-five adult-onset and 66 late-onset DM1 patients were included. Conduction delay on electrocardiogram was present in 123 of 275 (45%) adult-onset patients, compared with 24 of 66 (36%) late-onset patients (P = .218). DM1 subtype did not predict presence of conduction delay (odds ratio [OR] 0.706; confidence interval [CI] 0.405 to 1.230, P = .219). Subtype did predict indication for noninvasive ventilation (NIV) (late onset vs adult onset: OR, 0.254; CI, 0.104 to 0.617; P = .002) and 17% of late-onset patients required NIV compared with 40% of adult-onset patients. Muscular Impairment Rating Scale (MIRS) scores were significantly different between subtypes (MIRS 1 to 3 in 66% of adult onset vs 100% of late onset [P < .001]), as were DM1-activC scores (67 ± 21 in adult onset vs 87 ± 15 in late onset; P < .001). DISCUSSION: Although muscular phenotype was milder in late-onset compared with adult-onset DM1, the prevalence of conduction delay was comparable. Moreover, subtype was unable to predict the presence of cardiac conduction delay. Although adult-onset patients had an increased risk of having an NIV indication, 17% of late-onset patients required NIV. Despite different muscular phenotypes, screening for multiorgan involvement should be equally thorough in late-onset as in adult-onset DM1.

Different assessment tools to detect sarcopenia in patients with Parkinson's disease.

Introduction: Sarcopenia and Parkinson's disease are closely related diseases of the elderly population leading to progressive disability and nursing-dependent care. Objective: The aim of this study was to estimate the prevalence of sarcopenia in PD patients with three different approaches: (1) the screening tool SARC-F, (2) EWGSOP-1 criteria, and (3) EWGSOP-2 criteria. Moreover, we aimed to evaluate the diagnostic accuracy of the screening tool SARC-F to detect sarcopenia according to the updated EWGSOP-2 criteria. Methods: Eighty-one patients with Parkinson's disease aged 65 years and above were interviewed in a cross-sectional study at a tertiary referral center. All patients were screened with the SARC-F questionnaire and were evaluated for motor and non-motor symptoms, exercise, quality of life, and frailty. Muscle mass was assessed with bioelectrical impedance analysis, handgrip strength with a dynamometer, and gait speed was assessed with the 8-m walk test. EWGSOP-2 criteria were considered the gold standard to diagnose sarcopenia in our study. Results: Eighty-one patients were evaluated (mean age: 73.82; SD 5.30). The prevalence of sarcopenia was 28.4% according to the EWGSOP-2 criteria. The concordance between EWGSOP-2 and EWGSOP-1 was poor (weighted kappa of 0.361[95% 0.164-0.557]). The sensitivity of the SARC-F screening test for detecting sarcopenia was 60.9%. The corresponding AUC in the ROC curve analysis showed 0.598 (0.462, 0.734 CI). The item assessing strength was found to have the highest sensitivity (69.6%). Conclusion: Sarcopenia prevalence in patients with PD in Tirol, Austria is higher with EWGSOP-1 criteria compared to EWGSOP-2 criteria. The sensitivity and specificity of the SARC-F scale to detect sarcopenia in this population are poor.

Muscle ultrasound is a sensitive biomarker in oculopharyngeal muscular dystrophy.

INTRODUCTION/AIMS: Oculopharyngeal muscular dystrophy (OPMD) is a late-onset, progressive muscle disease. Quantitative muscle ultrasound (QMUS) assesses structural changes in muscles and is a sensitive biomarker in neuromuscular disorders. Our aim of this study was to determine whether QMUS can detect muscle pathology and can be used as longitudinal imaging biomarker in OPMD. METHODS: Genetically confirmed OPMD patients, recruited by their treating physicians or from the national neuromuscular database, were examined twice, 20 months apart, using QMUS of orofacial and limb muscles, and measurements of functional capacity and muscle strength. Absolute echo intensity (AEI) and muscle thickness of all muscles were analyzed and correlated with clinical data. RESULTS: The tongue, deltoid, iliopsoas, rectus femoris, and soleus muscles showed increased AEI at baseline compared with normal values in 43 OPMD patients, with the rectus femoris being most often affected (51%).The AEI and muscle thickness of 9 of 11 muscles correlated significantly with the motor function measure, 10-step stair test, swallowing capacity, dynamometry, Medical Research Council grade, tongue strength, and bite force (r = 0.302 to -0.711). Between baseline and follow-up, deterioration in AEI was found for the temporalis, tongue, and deltoid muscles, and decreased muscle thickness was detected for the temporalis, masseter, digastric, tongue, deltoid, iliopsoas, and soleus muscles (P < .05). No relation was found between the change in AEI and repeat length or disease duration. DISCUSSION: QMUS detected muscle pathology and disease progression in OPMD over 20 months. We conclude that QMUS should be considered as a biomarker in treatment trials.

Long-term follow-up of respiratory function in facioscapulohumeral muscular dystrophy.

OBJECTIVE: To evaluate the 5-year change in respiratory function in patients with facioscapulohumeral muscular dystrophy (FSHD). METHODS: Genetically confirmed patients with FSHD aged ≥ 18 years were examined twice over five years. Forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) were measured using hand-held spirometry with a face mask. Several clinical outcome measures were correlated to respiratory function. RESULTS: Ninety-two patients were included (57% male, age 18-75 years). At baseline, the spirometry outcomes of 41 patients showed a restrictive ventilatory pattern (FVC < 80% and FEV1/FVC ≥ 70% of predicted) and of 48 patients at follow-up. The mean FVC decreased from baseline to follow-up from 79.0 to 76.7% predicted (p = 0.021). This decrease was driven by a subgroup of 15 patients who had a deterioration of FVC of > 10% predicted. The subgroup of 15 patients was more severely affected at baseline (p = 0.002 for FSHD clinical score and 0.007 for Ricci score). They developed more frequently spinal and thorax deformities (p < 0.001 for kyphoscoliosis and 0.012 for pectus excavatum) and had a larger decline in axial muscle function (p = 0.020). Only weak correlations were found between the change in FVC% predicted and the change in clinical scores between baseline and follow-up. INTERPRETATION: Respiratory function remained stable in most patients with FSHD, but a subgroup of patients showed a pronounced deterioration. They showed more severe muscle weakness including the leg muscles at baseline (Ricci score ≥ 6), had spinal and thorax deformities and a relatively fast decline in axial muscle function at follow-up.

Behavioural Impairment and Frontotemporal Dementia in Oculopharyngeal Muscular Dystrophy.

Some patients with Oculopharyngeal Muscular Dystrophy (OPMD) develop frontotemporal dementia (FTD). The prevalence and clinical correlates of behavioural impairment, including FTD, is unknown in OPMD.24 OPMD patients and their proxies completed a questionnaire concerning behavioural impairment (ALS-FTD-Q). We examined proportions with mild or severe behavioural changes, according to validated cut-off proxy scores. We examined correlations with the Hospital Anxiety and Depression Scale (HADS), the Short Form Health Survey (SF-36), motor symptoms, genotype and disease duration.In this small patient sample, behavioural impairment was present in 29%of OPMD patients; in 17%the severity of symptoms was compatible with bvFTD. Correlations were small to medium.

Exploring the influence of smoking and alcohol consumption on clinical severity in patients with facioscapulohumeral muscular dystrophy.

Despite the growing knowledge on the (epi)genetic background of facioscapulohumeral muscular dystrophy (FSHD), the substantial variability in disease severity that exists between FSHD patients is not fully understood. We hypothesized that smoking and alcohol consumption are disease modifiers in FSHD and contribute to the variability in disease severity, because they are both associated with higher levels of oxidative stress in muscle tissue. Oxidative stress is known to influence FSHD muscle tissue. One hundred and ninety-eight genetically confirmed FSHD patients completed a questionnaire from which the number of packyears of smoking and the lifetime cumulative alcohol units consumed were calculated. Disease severity was determined by the FSDH evaluation score. Multiple linear regression analyses showed that both the number of packyears and the amount of alcohol consumption did not influence disease severity (respectively B = 0.025, ΔR2=0.006, p = 0.231; and B = 0.000, ΔR2=0.004, p = 0.406). Although smoking and excessive alcohol consumption are unhealthy habits which should be discouraged, these results show that smoking and alcohol consumption have no clinically meaningful modifying effect on disease severity in FSHD patients. However, prospective data should show whether alcohol consumption and smoking influence disease progression rate.

Longitudinal Assessment of Strength, Functional Capacity, Oropharyngeal Function, and Quality of Life in Oculopharyngeal Muscular Dystrophy.

ObjectiveOculopharyngeal muscular dystrophy (OPMD) is a late-onset, progressive muscle disease. Disease progression is known to be slow, but details on the natural history remain unknown. We aimed to examine the natural history of OPMD in a large nationwide cohort to determine clinical outcome measures that capture disease progression and can be used in future clinical trials.MethodsPatients, invited by their treating physicians or from the national neuromuscular database, and invited family members, were examined twice, 20 months apart, using fixed dynamometry, MRC grading, maximum bite force and isometric tongue strength, Motor Function Measure (MFM), 10-step stair test, maximum swallowing-, chewing-, and speech-tasks and quality of life assessments.ResultsDisease progression was captured by 8 out of 18 measures over 20 months in forty-three genetically confirmed OPMD patients. The largest deterioration was seen in deltoid muscle strength (-27% (range -17 - -37%)), followed by the quadriceps (-14% (range -6 - -23%)), iliopsoas (-12.2%), tongue (-9.9%) and MRC sum-score (-2.5%). The 10-step stair test (-12.5%), MFM part D1 (-7.1%), and maximum repetition rate of /pa/ (-5.3%) showed a significant decrease as well (all p<0.05). Domain 'Physical functioning' of the SF-36 Health Survey significantly deteriorated (p=0.044). No relationship was found between disease progression and genotype or disease duration (p>0.05).ConclusionsDespite the slow disease progression of OPMD, this study showed that several outcome measures detected progression within 20 months. The deltoid muscle strength, measured by fixed dynamometry, showed the greatest decline. This longitudinal data provides clinical outcome measures that can be used as biomarkers in future clinical trials.

The facioscapulohumeral muscular dystrophy Rasch-built overall disability scale (FSHD-RODS).

BACKGROUND AND OBJECTIVES: Facioscapulohumeral muscular dystrophy (FHSD) is a debilitating inherited muscle disease for which various therapeutic strategies are being investigated. Thus far, little attention has been given in FSHD to the development of scientifically sound outcome measures fulfilling regulatory authority requirements. The aim of this study was to design a patient-reported Rasch-built interval scale on activity and participation for FSHD. METHODS: A pre-phase FSHD-Rasch-built overall disability scale (pre-FSHD-RODS; consisting of 159 activity/participation items), based on the World Health Organization international classification of disease-related functional consequences was completed by 762 FSHD patients (Netherlands: n = 171; UK: n = 287; United States: n = 221; France: n = 52; Australia: n = 32). A proportion of the patient cohort completed it twice (n = 230; interval 2-4 weeks; reliability studies). The pre-FSHD-RODS was subjected to Rasch analyses to create a model fulfilling its requirements. Validity studies were performed through correlation with the motor function measure. RESULTS: The pre-FSHD-RODS did not meet the Rasch model expectations. Based on determinants such as misfit statistics and misfit residuals, differential item functioning, and local dependency, we systematically removed items until a final 38-inquiry (originating from 32 items; six items split) FSHD-RODS was constructed achieving Rasch model expectations. Adequate test-retest reliability and (cross-cultural and external) validity scores were obtained. CONCLUSIONS: The FSHD-RODS is a disease-specific interval measure suitable for detecting activity and participation restrictions in patients with FSHD with good item/person reliability and validity scores. The use of this scale is recommended in the near future, to determine the functional deterioration slope in FSHD per year as a preparation for the upcoming clinical intervention trials in FSHD.

Rasch analysis to evaluate the motor function measure for patients with facioscapulohumeral muscular dystrophy.

Patient-relevant outcome measures for facioscapulohumeral muscular dystrophy (FSHD) are needed. The motor function measure (MFM) is an ordinal-based outcome measure for neuromuscular disorders, but its suitability to measure FSHD patients is questionable. Here, we performed Rasch analyses on MFM data from 194 FSHD patients to assess clinimetric properties in this patient group. Both the total scale and its three domains were analyzed (D1: standing position and transfers; D2: axial and proximal motor function; D3: distal motor function). Fit to the Rasch model, sample-item targeting, individual item fit, threshold ordering, sex- and age-based differential item functioning, response dependency and unidimensionality were assessed. Rasch analysis revealed multiple limitations of the MFM for FSHD, the most important being a large ceiling effect and suboptimal sample-item targeting, which were most pronounced for domains D2 and D3. There were disordered thresholds for most items, often resulting in items functioning in a dichotomous fashion. It was not possible to remodel the MFM into a Rasch-built interval scale. Remodeling of domain D1 into an interval scale with adequate fit statistics was achieved, but sample-item targeting remained suboptimal. Therefore, the MFM should be used with caution in FSHD patients, as it is not optimally suited to measure functional abilities in this patient group.

Muscle involvement in SARS-CoV-2 infection.

BACKGROUND AND PURPOSE: Since the outbreak of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic, several reports indicated neurological involvement in COVID-19 disease. Muscle involvement has also been reported as evidenced by creatine kinase (CK) elevations and reports of myalgia. METHODS: Creatine kinase, markers of inflammation, pre-existing diseases and statin use were extracted from records of Austrian hospitalised COVID-19 patients. Disease severity was classified as severe in case of intensive care unit (ICU) admission or mortality. COVID-19 patients were additionally compared to an historical group of hospitalised influenza patients. RESULTS: Three hundred fifty-one patients with SARS-CoV-2 and 258 with influenza were included in the final analysis. CK was elevated in 27% of COVID-19 and in 28% of influenza patients. CK was higher in severe COVID-19 as were markers of inflammation. CK correlated significantly with inflammation markers, which had an independent impact on CK when adjusted for demographic variables and disease severity. Compared to influenza patients, COVID-19 patients were older, more frequently male, had more comorbidities, and more frequently had a severe disease course. Nevertheless, influenza patients had higher baseline CK than COVID-19, and 35.7% of intensive care unit (ICU)-admitted patients had CK levels >1,000 U/L compared to only 4.7% of ICU-admitted COVID-19 patients. CONCLUSIONS: HyperCKemia occurs in a similar frequency in COVID-19 and influenza infection. CK levels were lower in COVID-19 than in influenza in mild and severe disease. CK levels strongly correlate with disease severity and markers of inflammation. To date, it remains unclear whether hyperCKemia is due to a virus-triggered inflammatory response or direct muscle toxicity.

Swallowing, Chewing and Speaking: Frequently Impaired in Oculopharyngeal Muscular Dystrophy.

BACKGROUND: Oculopharyngeal muscular dystrophy (OPMD) is a late onset progressive neuromuscular disorder. Although dysphagia is a pivotal sign in OPMD it is still not completely understood. OBJECTIVE: The aim of this study was to systematically investigate oropharyngeal functioning in a large OPMD population. METHODS: Forty-eight genetically confirmed OPMD patients completed questionnaires, performed clinical tests on swallowing, chewing, speaking, tongue strength and bite force, and underwent videofluoroscopy of swallowing. Descriptive statistics was used for all outcomes and logistic regression to investigate predictors of abnormal swallowing. RESULTS: Eighty-two percent reported difficulties with swallowing, 27% with chewing and 67% with speaking. Patients performed significantly worse on all oropharyngeal tests compared to age-matched controls except for bite force. Also asymptomatic carriers performed worse than controls: on chewing time, swallowing speed and articulation rate. During videofluoroscopy, all patients (except one asymptomatic) had abnormal residue and 19% aspirated. Independent predictors of abnormal residue were reduced swallowing capacity for thin liquids (OR 10 mL = 0.93; 20 mL = 0.95) and reduced tongue strength for thick liquids (OR 10 mL = 0.95); 20 mL = 0.90). Aspiration of thin liquids was predicted by disease duration (OR = 1.11) and post-swallow residue with 20 mL (OR = 4.03). CONCLUSION: Next to pharyngeal dysphagia, chewing and speaking are also frequently affected in OPMD patients, even in asymptomatic carriers. Residue after swallowing is a very early sign, while aspiration is a later sign in OPMD. For clinical follow-up monitoring of subjective complaints, swallowing capacity and tongue strength seems relevant.

Age-Associated Salivary MicroRNA Biomarkers for Oculopharyngeal Muscular Dystrophy.

Small non-coding microRNAs (miRNAs) are involved in the regulation of mRNA stability. Their features, including high stability and secretion to biofluids, make them attractive as potential biomarkers for diverse pathologies. This is the first study reporting miRNA as potential biomarkers for oculopharyngeal muscular dystrophy (OPMD), an adult-onset myopathy. We hypothesized that miRNA that is differentially expressed in affected muscles from OPMD patients is secreted to biofluids and those miRNAs could be used as biomarkers for OPMD. We first identified candidate miRNAs from OPMD-affected muscles and from muscles from an OPMD mouse model using RNA sequencing. We then compared the OPMD-deregulated miRNAs to the literature and, subsequently, we selected a few candidates for expression studies in serum and saliva biofluids using qRT-PCR. We identified 126 miRNAs OPMD-deregulated in human muscles, but 36 deregulated miRNAs in mice only (pFDR < 0.05). Only 15 OPMD-deregulated miRNAs overlapped between the in humans and mouse studies. The majority of the OPMD-deregulated miRNAs showed opposite deregulation direction compared with known muscular dystrophies miRNAs (myoMirs), which are associated. In contrast, similar dysregulation direction was found for 13 miRNAs that are common between OPMD and aging muscles. A significant age-association (p < 0.05) was found for 17 OPMD-deregulated miRNAs (13.4%), whereas in controls, only six miRNAs (1.4%) showed a significant age-association, suggesting that miRNA expression in OPMD is highly age-associated. miRNA expression in biofluids revealed that OPMD-associated deregulation in saliva was similar to that in muscles, but not in serum. The same as in muscle, miRNA expression levels in saliva were also found to be associated with age (p < 0.05). Moreover, the majority of OPMD-miRNAs were found to be associated with dysphagia as an initial symptom. We suggest that levels of specific miRNAs in saliva can mark muscle degeneration in general and dysphagia in OPMD.

Laboratory Tests for Neuropathies: What to do and to Avoid.

OBJECTIVES: laboratory tests for work-up of hereditary and acquired neuropathies of peripheral nerves are frequently uncritically utilized. This overview focuses on the most common laboratory tests and investigations needed for diagnosing PNPs by the general neurologist. METHOD: Literature search. RESULTS: laboratory tests recommended for the work-up of hereditary and acquired neuropathies should be chosen according to the individual and family history, clinical presentation, and electrophysiological findings. Laboratory tests should be selected specifically according to the suspected type of neuropathy to avoid unnecessary tests and expenses. Work-up should include as few samples as necessary for uncovering the etiology and should consider the sensitivity/specificity of the tests applied.. Basic screening tests for neuropathies should include a blood cell count, thyroid, renal and liver function tests, blood glucose levels, HbA1c, vitamin-B12, and immunofixation. Other laboratory investigations should be carried out only if a specific phenotype is present or if unexpected changes of the disease course occur. In these cases referral to a neuromuscular center is recommended. CONCLUSIONS: Laboratory tests are helpful for the diagnosis of acquired and hereditary neuropathies but these tests should be ordered according to the history, clinical presentation and findings on electrophysiological investigations. If basic laboratory parameters fail to uncover the etiology, patients should be referred to a center specialized in neuromuscular disorders.