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.

A study of impairments in oculopharyngeal muscular dystrophy.

INTRODUCTION: In this study we aimed to document the prevalence and age of onset of motor impairments and other key symptoms in oculopharyngeal muscular dystrophy (OPMD). METHODS: Retrospective chart review of patients followed at the Saguenay Neuromuscular Clinic (Quebec, Canada). RESULTS: A total of 333 participants with the (GCN)13 mutation were included. Before the age of 75 years, 27% of them had walking limitations, 14% could not climb stairs independently, and 14% used a wheelchair for long distances or daily living. The median age of onset was 54 years for ptosis and dysphagia and 58 years for lower limb proximal weakness. Other frequent symptoms included fatigue, pharyngeal pooling of thickened secretions, and dysphonia. The median age at death was 77 years and the main cause was respiratory disease. DISCUSSION: This study provides important information to help anticipatory guidance for affected people and for the development of therapeutic trials in OPMD.

Patient-reported disease burden in oculopharyngeal muscular dystrophy.

INTRODUCTION: There is currently little evidence regarding oculopharyngeal muscular dystrophy (OPMD) disease burden reported by patients. In this study we aim to elicit direct patient input regarding OPMD disease burden. METHODS: We conducted semistructured interviews with 25 participants with genetically confirmed OPMD and a wide range of disease duration (15 ± 8 years). Using the Framework Technique, themes and categories were then extracted. RESULTS: Analyses revealed 7 themes (physical impact, mental impact, social impact, perception of progression, treatment perceptions, coping strategies, and access to disease information), encompassing 27 categories of OPMD disease burden. The most frequent categories were related to dysphagia, coping strategies for dysphagia, and impaired mobility. DISCUSSION: This study demonstrates the importance of considering, when providing clinical care, the broad range of coping strategies patients use to deal with OPMD symptoms, especially dysphagia, to properly assess limitations and monitor real disease progression.

The requirement for a disease-specific patient-reported outcome measure of dysphagia in oculopharyngeal muscular dystrophy.

INTRODUCTION: There is no patient-reported outcome (PRO) questionnaire specifically designed to assess oropharyngeal dysphagia in oculopharyngeal muscular dystrophy (OPMD). To select a suitable questionnaire, content validity of the existing questionnaires must be assessed. This study sought (1) to identify dysphagia-related symptoms in OPMD and (2) to assess content validity of currently available PRO for the assessment of dysphagia severity in OPMD. METHODS: A two-step literature review was conducted of dysphagia-related symptom identification and oropharyngeal dysphagia-related PRO. Symptoms were validated with an expert panel by using a Delphi survey. Content validity of PRO questionnaires was documented through content analysis. RESULTS: Ten PRO questionnaires were identified. None of the questionnaires cover the entire symptom spectrum in OPMD and thus lack content validity. DISCUSSION: The development and validation of a new PRO questionnaire to assess dysphagia in OPMD is required to establish the importance of symptomatic relief from new treatments. Muscle Nerve 59:445-450, 2019.

A Preliminary Videofluoroscopic Investigation of Swallowing Physiology and Function in Individuals with Oculopharyngeal Muscular Dystrophy (OPMD).

Dysphagia is one of the primary symptoms experienced by individuals with Oculopharyngeal Muscular Dystrophy (OPMD). However, we lack understanding of the discrete changes in swallowing physiology that are seen in OPMD, and the resulting relationship to impairments of swallowing safety and efficiency. This study sought to describe the pathophysiology of dysphagia in a small sample of patients with OPMD using a videofluoroscopy examination (VFSS) involving 3 × 5 mL boluses of thin liquid barium (22% w/v). The aim of this study is to extend what is known about the pathophysiology of dysphagia in OPMD, by quantifying changes in swallow timing, kinematics, safety, and efficiency, measured from VFSS. This study is a secondary analysis of baseline VFSS collected from 11 adults (4 male), aged 48-62 (mean 57) enrolled in an industry-sponsored phase 2 therapeutic drug trial. Blinded raters scored the VFSS recordings for safety [Penetration-Aspiration Scale (PAS)], efficiency [Normalized Residue Ratio Scale (NRRS)], timing [Pharyngeal Transit Time (PTT), Swallow Reaction Time (SRT), Laryngeal Vestibule Closure Reaction Time (LVCrt), Upper Esophageal Sphincter Opening Duration (UESD)], and kinematics (hyoid movement, pharyngeal constriction, UES opening width). Impairment thresholds from existing literature were defined to characterize swallowing physiology and function. Further, Fisher's Exact tests and Pearson's correlations were used to conduct a preliminary exploration of associations between swallowing physiology (e.g., kinematics, timing) and function (i.e., safety, efficiency). Compared to published norms, we identified significant differences in the degree of maximum pharyngeal constriction, hyoid movement distance and speed, as well as degree and timeliness of airway closure. Unsafe swallowing (PAS ≥ 3) was seen in only 3/11 patients. By contrast, clinically significant residue (i.e., NRRS scores ≥ 0.09 vallecular; ≥ 0.2 pyriform) was seen in 7/11 patients. Fisher's Exact tests revealed associations between prolonged SRT, PTT, and unsafe swallowing. Weak associations were also identified between post-swallow residue and poor pharyngeal constriction during the swallow. Detailed analysis of swallowing physiology in this series of adults with OPMD aligns with impaired muscular function (e.g., reduced pharyngeal constriction, incomplete laryngeal vestibule closure) associated with the disease, and primary functional challenges with swallow efficiency. Further work is needed to explore a greater range of food and liquid textures, and to identify additional physiological mechanisms underlying swallowing impairment in OPMD.

Involvement of pelvic girdle and proximal leg muscles in early oculopharyngeal muscular dystrophy.

Although limb girdle weakness is not part of the major diagnostic criteria of oculopharyngeal muscular dystrophy (OPMD), it has frequently been observed in the Dutch and other OPMD cohorts. In the Dutch cohort, this might be related to the relatively old age or the severity of the genetic defect. This patient-control study (14 OPMD patients and 12 controls) investigated the involvement of limb girdle muscles with a multidimensional approach in early OPMD. We assessed functional abilities, disease impact, physical activity, muscle strength, histopathology and fatty infiltration using questionnaires, actometer, functional tests, manual and quantitative muscle testing, muscle biopsy and muscle MRI. The study showed that involvement of pelvic girdle and proximal leg can be a relatively early feature of OPMD, resulting in impaired daily life activities. The fat fraction of the hip adductors and hamstrings was significantly higher in OPMD patients than in controls. Future studies should include assessment of hip flexors, hip adductors and hamstrings (muscle strength measurements and MRI), functional tests and questionnaires. These findings are important in future diagnostics, management and for the design of outcome measures in trials.

PABPN1 gene therapy for oculopharyngeal muscular dystrophy.

Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant, late-onset muscle disorder characterized by ptosis, swallowing difficulties, proximal limb weakness and nuclear aggregates in skeletal muscles. OPMD is caused by a trinucleotide repeat expansion in the PABPN1 gene that results in an N-terminal expanded polyalanine tract in polyA-binding protein nuclear 1 (PABPN1). Here we show that the treatment of a mouse model of OPMD with an adeno-associated virus-based gene therapy combining complete knockdown of endogenous PABPN1 and its replacement by a wild-type PABPN1 substantially reduces the amount of insoluble aggregates, decreases muscle fibrosis, reverts muscle strength to the level of healthy muscles and normalizes the muscle transcriptome. The efficacy of the combined treatment is further confirmed in cells derived from OPMD patients. These results pave the way towards a gene replacement approach for OPMD treatment.

Comparison of Two Polypropylene Frontalis Suspension Techniques in 92 Patients With Oculopharyngeal Muscular Dystrophy.

PURPOSE: To compare the functional outcome of the polypropylene trapezoid frontalis suspension with the polypropylene modified Crawford frontalis suspension in a large cohort of patients with oculopharyngeal muscular dystrophy. METHODS: Retrospective, nonrandomized comparative case series. Patients with oculopharyngeal muscular dystrophy who underwent bilateral polypropylene frontalis suspension were selected for chart review. Main outcome measures were margin reflex distance, duration of surgery, and ptosis recurrence. RESULTS: Ninety-two patients qualified for chart review; 39 patients underwent the trapezoid sling and 53 patients the modified Crawford sling. There was no difference in preoperative margin reflex distance or levator function between the 2 surgical groups. Postoperative improvement in margin reflex distance was 2.95 ± 1.56 mm in the trapezoid group compared with 2.85 ± 1.65 mm in the modified Crawford group (p = 0.67). Duration of surgery was 40.49 ± 13.33 minutes in the trapezoid group compared with 53.77 ± 16.04 minutes in the modified Crawford group (p < 0.001). Five percent of eyes in the trapezoid group had ptosis recurrence compared with 13% of eyes in the modified Crawford group (p = 0.07). CONCLUSION: Both polypropylene frontalis suspension techniques generated an equivalent increase in margin reflex distance. However, the trapezoid frontalis suspension required less operative time and trended toward a lower rate of ptosis recurrence.

Correlation between PABPN1 genotype and disease severity in oculopharyngeal muscular dystrophy.

OBJECTIVE: Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant adult-onset disease characterized by progressive ptosis, dysphagia, and proximal limb weakness. The genetic cause is an expanded (GCN)n mutation in the PABPN1 gene encoding for the polyadenylate-binding protein nuclear 1. We hypothesized a potential correlation between the size of the (GCN)n expansion and the severity of the phenotype. To do this, we characterized the distribution of the genotypes as well as their correlation with age at diagnosis and phenotypical features in a large cohort of heterozygous and homozygous patients with OPMD in France with a confirmed molecular diagnosis of PABPN1. METHODS: We explored 354 unrelated index cases recruited between 1999 and 2014 in several neuromuscular centers in France. RESULTS: This cohort allowed us to characterize the frequency of mutated alleles in the French population and to demonstrate a statistical correlation between the size of the expansion and the mean age at diagnosis. We also confirmed that homozygous patients present with a more severe disease. CONCLUSIONS: It has been difficult to establish phenotype-genotype correlations because of the rare nature of this disease. Our work demonstrates that patients with OPMD with longer PABPN1 expansion are on average diagnosed at an earlier age than patients with a shorter expansion, confirming that polyalanine expansion size plays a role in OPMD, with an effect on disease severity and progression.

Intranuclear Aggregates Precede Clinical Onset in Oculopharyngeal Muscular Dystrophy.

BACKGROUND: Oculopharyngeal muscular dystrophy (OPMD) has long been characterized by a combination of bilateral ptosis and dysphagia and subsequent limb girdle weakness. The role of the typical intranuclear inclusion in the pathophysiology is unresolved. OBJECTIVE: The aim of this study was to describe the clinical and histopathological features of oculopharyngeal muscular dystrophy (OPMD). We examined this in a Dutch cohort including presymptomatic Ala-expanded-PABPN1 carriers and late symptomatic patients. METHODS: We performed a prospective, observational study in OPMD patients and adult children of genetically confirmed OPMD patients. The study includes a structured history, a detailed neurological examination, muscle histology and biochemical analysis. Forty patients and 18 adult children participated in this study, among whom were six presymptomatic mutation carriers. One patient died during the study and had given permission to autopsy. RESULTS: In addition to the characteristic OPMD symptoms including ptosis and dysphagia, other symptoms such as limb girdle and axial weakness, and external ophthalmoplegia were frequently observed. Intranuclear aggregates were observed in the biopsies of presymptomatic carriers. Biochemical analysis of the biopsies of the presymptomatic carriers showed no mitochondrial dysfunction. The autopsy showed that muscle weakness correlated with histopathological findings in five different muscles in an individual patient. CONCLUSIONS: The main findings of this nationwide study are the presence of intranuclear aggregates before clinical onset and the absence of mitochondrial changes in Ala-expanded-PABPN1 carriers. This indicates that the expression of Ala-expanded-PABPN1 causes the formation of nuclear aggregates before the onset of muscle weakness. Normal results of biochemical analysis in presymptomatic carriers suggest that possible mitochondrial dysfunction occurs later. Furthermore we confirmed that limb girdle weakness occurs frequently in Dutch OPMD patients. This study thus expands the OPMD research towards characterization of presymptomatic carriers.

Oculopharyngeal Weakness, Hypophrenia, Deafness, and Impaired Vision: A Novel Autosomal Dominant Myopathy with Rimmed Vacuoles.

BACKGROUND: Myopathies with rimmed vacuoles are a heterogeneous group of muscle disorders with progressive muscle weakness and varied clinical manifestations but similar features in muscle biopsies. Here, we describe a novel autosomal dominant myopathy with rimmed vacuoles in a large family with 11 patients of three generations affected. METHODS: A clinical study including family history, obstetric, pediatric, and development history was recorded. Clinical examinations including physical examination, electromyography (EMG), serum creatine kinase (CK), bone X-rays, and brain magnetic resonance imaging (MRI) were performed in this family. Open muscle biopsies were performed on the proband and his mother. To find the causative gene, the whole-exome sequencing was carried out. RESULTS: Disease onset was from adolescence to adulthood, but the affected patients of the third generation presented an earlier onset and more severe clinical manifestations than the older generations. Clinical features were characterized as dysarthria, dysphagia, external ophthalmoplegia, limb weakness, hypophrenia, deafness, and impaired vision. However, not every patient manifested all symptoms. Serum CK was mildly elevated and EMG indicated a myopathic pattern. Brain MRI showed cerebellum and brain stem mildly atrophy. Rimmed vacuoles and inclusion bodies were observed in muscle biopsy. The whole-exome sequencing was performed, but the causative gene has not been found. CONCLUSIONS: We reported a novel autosomal dominant myopathy with rimmed vacuoles characterized by dysarthria, dysphagia, external ophthalmoplegia, limb weakness, hypophrenia, deafness, and impaired vision, but the causative gene has not been found and needs further study.

An improved electrical impedance myography (EIM) tongue array for use in clinical trials.

OBJECTIVES: Electrical impedance myography (EIM) measurements of the tongue could provide valuable information about bulbar dysfunction in amyotrophic lateral sclerosis (ALS). A prototype tongue depressor EIM array produced gag reflexes. The objectives of this study were to determine the reliability, mean phase values, and tolerability of tongue EIM measurements using a smaller electrode array. METHODS: Tongue EIM measurements were performed in a total of 31 healthy individuals and four neuromuscular patients with lingual abnormalities. Reliability was assessed by calculating the intraclass correlation coefficient (ICC) and percent difference in addition to performing Bland-Altman analyses. Standard descriptive statistics, including results of a Mann-Whitney test, were also determined. RESULTS: At the 50 kHz frequency, the ICCs for intra- and inter-rater reliability were 0.76 with 5.17% difference and 0.78 with 5.34% difference respectively. The mean EIM phase values of healthy participants (11.61° ± 1.00°) and patients (9.87° ± 1.28°) were significantly different (p=0.0051). None of the participants experienced gag reflexes or discomfort. CONCLUSIONS: The small tongue array provided good inter- and intra-rater reliability, could preliminarily distinguish between healthy and diseased muscle, and was well-tolerated. SIGNIFICANCE: Biomarker information about tongue health could be more comfortably obtained with a smaller EIM array.

The relationship between physical symptoms and health-related quality of life in oculopharyngeal muscular dystrophy.

INTRODUCTION: Oculopharyngeal muscular dystrophy (OPMD) causes ptosis, dysphagia, and limb weakness. Health-related quality of life (HRQoL) and its relationship to physical symptoms was investigated. METHODS: The 36-item Short Form (SF-36) was completed by 89 participants in the U.S. OPMD Registry. Multiple hierarchical regression was used to determine the relative contributions of dysphagia severity and lower extremity functional impairment to the physical (PCS) and mental (MCS) components of the SF-36. RESULTS: HRQoL was reduced in OPMD compared with population norms. Lower extremity functional impairment explained a significant proportion of variance in PCS and MCS. Dysphagia symptom severity explained a moderate amount of variance only in MCS. Dysphagia symptom severity had the strongest associations with general health perception and social functioning domains. CONCLUSIONS: Lower extremity functional impairment in OPMD deserves attention due to its large influence on HRQoL. Both generic and dysphagia-specific measures are necessary to assess HRQoL in OPMD.

Dropped-head in recessive oculopharyngeal muscular dystrophy.

A 69-year-old woman presented a dropped head, caused by severe neck extensor weakness that had started two years before. She had also developed a mild degree of dysphagia, rhinolalia, eyelid ptosis and proximal limb weakness during the last months. EMG revealed myopathic changes. Muscle MRI detected fatty infiltration in the posterior neck muscles and tongue. Muscle biopsy revealed fiber size variations, sporadic rimmed vacuoles, small scattered angulated fibers and a patchy myofibrillar network. Genetic analysis revealed homozygous (GCN)11 expansions in the PABPN1 gene that were consistent with recessive oculopharyngeal muscular dystrophy (OPMD). There are a few reports of the recessive form, which has a later disease onset with milder symptoms and higher clinical variability than the typical dominantly inherited form. This patient, who is the first Italian and the eighth worldwide reported case of recessive OPMD, is also the first case of OPMD with dropped-head syndrome, which thus expands the clinical phenotype of recessive OPMD.

Orthoptic and video-oculographic analyses in oculopharyngeal muscular dystrophy.

INTRODUCTION: Mild ophthalmoparesis can be seen in oculopharyngeal muscular dystrophy (OPMD). METHODS: Orthoptic analysis included assessment of phoria/tropia, eye excursion, saccades, pursuit, stereoacuity, and Hess-Lancaster screen test. Video-oculography included fixation, horizontal and vertical saccades, and pursuit. RESULTS: Orthoptic abnormalities were: tropia (4 of 6); abnormal eye excursion (4 of 6, 78% involved lateral or superior rectus muscles); abnormal horizontal or vertical saccades (2 of 6); abnormal pursuit (0 of 6); abnormal stereoacuity (2 of 6); and pathological Hess-Lancaster screen (4 of 6). Video-oculographic abnormalities were present for: fixation (1 of 6); saccade latency (1 of 6); horizontal pursuit (3 of 6); and vertical pursuit (0 of 6). For horizontal saccades, mean velocity, peak velocity, and gain were pathological in 5 of 6, 5 of 6 (61% of pathological mean and peak velocities involved abducting eye movements), and 3 of 6, respectively. For vertical saccades, mean velocity, peak velocity, and gain were pathological in 4 of 6, 4 of 6 (53% involved upward movements), and 3 of 6, respectively. CONCLUSION: The data indicate preferential involvement of lateral and (to a lesser degree) superior rectus muscles in OPMD.

Factors affecting eyelid crease formation before and after silicone frontalis suspension for adult-onset myogenic ptosis.

PURPOSE: To evaluate factors that affect eyelid crease formation before and after frontalis suspension. DESIGN: Nonrandomized, comparative, interventional case series. METHODS: Sixty-three patients (125 eyes) with myogenic ptosis were included. Data collected included age, gender, previous surgeries, follow up, as well as pre- and postoperative margin reflex distance, palpebral fissure height, and levator function. Intraoperative maneuvers of incorporation of the levator aponeurosis into the skin closure, conservative fat excision, and conservative skin excision were recorded. Pre- and postoperative eyelid creases were graded by 2 masked, independent observers as "good," "fair," or "poor." RESULTS: The weighted κ coefficient between the graders was 0.68 (95% CI, 0.58-0.79) preoperatively and 0.70 (95% CI, 0.61-0.79) postoperatively. Evaluating preoperative eyelid crease grades, there was no significant difference with regard to age or gender (p = 0.83 or 0.69, respectively). Eyelid crease grade correlated with margin reflex distance (p = 0.0004) and palpebral fissure height (p = 0.002). There was no significant correlation of eyelid crease with levator function (p = 0.104). After frontalis sling, intraoperative maneuvers of incorporation of the levator aponeurosis into the incision, skin preservation, and fat preservation correlated with postoperative eyelid crease (p = 0.0004, 0.059, and 0.033, respectively). CONCLUSIONS: Preoperative levator function in patients with adult onset myogenic ptosis may be an inaccurate measure of true levator palpebrae strength. Reliance on levator function alone in decision making for surgical intervention in these patients may be misguided. The inclusion of the intraoperative maneuvers of incorporation of the levator aponeurosis into the skin incision and preservation of fat and skin results in a stronger eyelid crease after frontalis sling surgery.

Muscle weakness and speech in oculopharyngeal muscular dystrophy.

PURPOSE: We documented speech and voice characteristics associated with oculopharyngeal muscular dystrophy (OPMD). Although it is a rare disease, OPMD offers the opportunity to study the impact of myopathic weakness on speech production in the absence of neurologic deficits in a relatively homogeneous group of speakers. METHODS: Twelve individuals with OPMD and 12 healthy age-matched controls underwent comprehensive assessment of the speech mechanism including spirometry (respiratory support), nasometry (resonance balance), phonatory measures (pitch, loudness, and quality), articulatory measures (diadochokinetic rates, segment duration measures, spectral moments, and vowel space), tongue-to-palate strength measures during maximal isometric and speechlike tasks, quality-of-life questionnaire, and perceptual speech ratings by listeners. RESULTS: Individuals with OPMD had substantially reduced tongue strength compared to the controls. However, little impact on speech and voice measures or on speech intelligibility was observed except for slower diadochokinetic rates. CONCLUSIONS: Despite having less than half the maximal tongue strength of healthy controls, the individuals with OPMD exhibited minimal speech deficits. The threshold of weakness required for noticeable speech impairment may not have been reached by this group of adults with OPMD.