Muscle pain as a prominent feature of facioscapulohumeral muscular dystrophy (FSHD): four illustrative case reports

A diagnostic support system based on pain drawings: binary and k-disease classification of EDS, GBS, FSHD, PROMM, and a control group with Pain2D

BACKGROUND AND OBJECTIVE

The diagnosis of rare diseases (RDs) is often challenging due to their rarity, variability and the high number of individual RDs, resulting in a delay in diagnosis with adverse effects for patients and healthcare systems. The development of computer assisted diagnostic decision support systems could help to improve these problems by supporting differential diagnosis and by prompting physicians to initiate the right diagnostic tests. Towards this end, we developed, trained and tested a machine learning model implemented as part of the software called Pain2D to classify four rare diseases (EDS, GBS, FSHD and PROMM), as well as a control group of unspecific chronic pain, from pen-and-paper pain drawings filled in by patients.

METHODS

Pain drawings (PDs) were collected from patients suffering from one of the four RDs, or from unspecific chronic pain. The latter PDs were used as an outgroup in order to test how Pain2D handles more common pain causes. A total of 262 (59 EDS, 29 GBS, 35 FSHD, 89 PROMM, 50 unspecific chronic pain) PDs were collected and used to generate disease specific pain profiles. PDs were then classified by Pain2D in a leave-one-out-cross-validation approach.

RESULTS

Pain2D was able to classify the four rare diseases with an accuracy of 61-77% with its binary classifier. EDS, GBS and FSHD were classified correctly by the Pain2D k-disease classifier with sensitivities between 63 and 86% and specificities between 81 and 89%. For PROMM, the k-disease classifier achieved a sensitivity of 51% and specificity of 90%.

CONCLUSIONS

Pain2D is a scalable, open-source tool that could potentially be trained for all diseases presenting with pain.

[Rare diseases in the differential diagnosis of myalgia]

Myalgia describes pain in the skeletal muscles. According to the current German clinical guidelines from 2020 (AWMF register number: 030/051), the initial diagnostic assessment consists of the anamnesis, clinical examination, electrophysiological examination and standard laboratory tests. Additional special examinations, such as molecular genetic investigations, special laboratory tests, medical imaging and muscle biopsy are only needed in certain cases. This article focuses on rare neurological diseases that are classically associated with myalgia. In this context etiologically different diseases are considered, whereby some genetically linked diseases (fascioscapulohumeral dystrophy, FSHD, dystrophia myotonica, McArdle's disease, Pompe's disease, limb girdle muscular dystrophy) are contrasted with diseases with an (auto)immune-related pathogenesis (stiff-person syndrome, Isaacs syndrome). The aspects relevant for the diagnosis are particularly highlighted. The therapeutic aspects of the diseases are not part of this article.

[Rare diseases in the differential diagnosis of myalgia]

Myalgia describes pain in the skeletal muscles. According to the current German clinical guidelines from 2020 (AWMF register number: 030/051), the initial diagnostic assessment consists of the anamnesis, clinical examination, electrophysiological examination and standard laboratory tests. Additional special examinations, such as molecular genetic investigations, special laboratory tests, medical imaging and muscle biopsy are only needed in certain cases. This article focuses on rare neurological diseases that are classically associated with myalgia. In this context etiologically different diseases are considered, whereby some genetically linked diseases (fascioscapulohumeral dystrophy, FSHD, dystrophia myotonica, McArdle's disease, Pompe's disease, limb girdle muscular dystrophy) are contrasted with diseases with an (auto)immune-related pathogenesis (stiff-person syndrome, Isaacs syndrome). The aspects relevant for the diagnosis are particularly highlighted. The therapeutic aspects of the diseases are not part of this article.

Prevalence of Pain within Limb Girdle Muscular Dystrophy R9 and Implications for Other Degenerative Diseases

Our primary aim was to establish the prevalence of pain within limb girdle muscular dystrophy R9 (LGMDR9). As part of the Global FKRP Registry, patients are asked to complete the Short Form McGill Pain Questionnaire (SF-MPQ) annually. We used the results of this questionnaire to determine individuals’ maximum pain score and total pain score and examined overall pain intensity and associations between pain intensity and LGMDR9 genotypes, age, and ambulatory status. We also considered the pain descriptors used and pain progression over time. Of the 502 patients, 87% reported current pain and 25% reported severe current pain. We found no associations in pain severity between the different genotypes of LGMDR9. However, we did find statistically significant associations between pain severity and ambulatory status and between our paediatric and adult populations. We found pain descriptors to be more common words that one may associate with non-neural pain, and we found that a significant number of individuals (69%) reported a fluctuating pain pattern over time. We concluded that pain should be considered a significant issue among individuals with LGMDR9 requiring management. Implications regarding assessment of pain for other degenerative diseases are discussed.

The Prevalence, Characteristics and Impact of Chronic Pain in People With Muscular Dystrophies: A Systematic Review and Meta-Analysis

Chronic pain is a frequent, yet under-recognized and under-assessed problem in people with muscular dystrophies (MDs). Knowledge of the prevalence and characteristics of chronic pain, and its impact on function and quality of life is limited and lacks systematic exploration. This article aims to systematically review and synthesize existing literature that addresses chronic pain prevalence, characteristics and impact in people with different types of MDs. The present meta-analysis showed that the estimated prevalence of chronic pain in MDs is high and appears to be similar across different diagnostic groups: 68% (95% CI: 52%-82%) in FSHD, 65% (95% CI: 51%-77%) in DM, 62% (95% CI: 50%-73%) in BMD/DMD, and 60% (95% CI: 48%-73%) in LGMD, although it should be noted that heterogeneity was high in some diagnostic groups. On average, people with FSHD and DM present with moderate pain intensity. The lumbar spine, shoulders and legs are the most frequent sites of chronic pain among people with FSHD, DM, BMD/DMD, and LGMD, with little variation. Diffuse pain across multiple body sites was reported by a notable proportion of these individuals. Chronic pain has a negative impact on daily life activities in people with MDs, and may also contribute to decreased quality of life. The protocol for this review has been published on PROSPERO (CRD42020168096). PERSPECTIVES: This is the first systematic review and meta-analysis exploring the prevalence, and nature and impact of chronic pain in people with MDs. The present study demonstrates how common chronic pain is across various MD populations and highlights the need for better recognition and understanding of the nature and impact of pain from health professionals.

Myalgia in myositis and myopathies

Myalgia is a common symptom of various neuromuscular disorders: myalgia occurs in metabolic muscle diseases, inflammatory muscle diseases, dystrophic myopathies and myotonic muscle disorders. Myalgia leads to a significantly reduced quality of life. Other muscular symptoms that are present along with myalgia often provide the clue towards a diagnosis and include weakness, cramps and myotonia as well as the type of pain. In addition, extramuscular symptoms like an erythema in dermatomyositis can lead to the correct diagnosis. Basic diagnostic workup includes a detailed medical history, full neurologic assessment, laboratory tests, EMG and nerve conduction studies. Muscle imaging, genetic testing and muscle biopsy may be required to make a diagnosis. Whenever possible, treatment should aim to improve or correct the underlying cause for myalgia such as inflammation or hypothyroidism. Symptomatic therapy includes different avenues: Myotonia can be treated with mexiletine. Carbamazepine or phenytoin can be used in myotonic syndromes, particularly with muscle cramps. Pregabalin, gabapentin, or amitriptyline can be tried in conditions with myalgic pain. This review summarizes the symptoms, diagnostic strategies, and therapeutic approach in neuromuscular disorders that present with myalgia.

Clinical features of facioscapulohumeral muscular dystrophy 1 in childhood

AIM

To explore the clinical course of patients presenting with facioscapulohumeral dystrophy type 1 (FSHD1) in childhood, with a view to identifying areas where they differed from older patients and where extra support or monitoring might be required.

METHOD

A retrospective case-notes review of children with FSHD1 seen at a tertiary paediatric neuromuscular centre between 2002 and 2016 was performed. Data collected included age at and nature of presentation, path to diagnosis, genetic testing results, motor function, and occurrence of extramuscular features and complications.

RESULTS

Eighteen children (11 females, seven males; mean [SD] age at latest review 13y 10mo [3y 9mo], range 8-19y) from 16 families were identified. Age at onset of FSHD1 correlated with the size of deletion (r=0.81) and most presentations were in children either younger than 5 years or older than 10 years. Children with onset before 5 years were more likely to present with non-muscular symptoms and to develop extramuscular pathology, including developmental and psychiatric issues, hearing or visual impairments, and problems involving respiratory function and nutrition. No cases of epilepsy or cardiac arrhythmia were identified but two children died.

INTERPRETATION

The complexity and severity of FSHD1 presenting in early childhood underlines the importance of a multidisciplinary approach to the disorder.

WHAT THIS PAPER ADDS

Young children often present with non-muscular pathology in facioscapulohumeral dystrophy type 1 (FSHD1), especially hearing loss. Age at onset in paediatric FSHD1 appears bimodal: under 5 years or in adolescence. Prolonged delays to diagnosis are common. Children with very early-onset FSHD1 may require nutritional and/or respiratory support. Developmental and psychiatric comorbidities are common.

Quality of life in adults with muscular dystrophy

BACKGROUND

Muscle weakness is a defining characteristic of Muscular Dystrophy (MD); however, yet while speculated, objective measures of muscle weakness has not been reported in relation to quality of life in adults with MD.

OBJECTIVES

1) compare the self-reported QoL of adults with Duchenne MD (DMD), Beckers MD (BMD), Limb-Girdle MD (LGMD) and Fascioscapulohumeral MD (FSHD, and a non-MD (CTRL) group; 2) present and compare between groups measures of Impairment (Muscle Strength and Activities of Daily Living) and Perception (Fatigue, Pain and Self-Efficacy); and 3) identify associations between QoL domains and measures of Impairment and Perception (See above).

METHODS

Seventy-Five males, including MD classifications DMD, BMD, LGMD, FSHD and CTRL, completed measures for QoL, Knee-Extension Maximal Voluntary Contraction (KEMVC), Fatigue, Pain, Self-Efficacy and Activities of Daily Living (ADL).

RESULTS

QoL was lower across many domains in MD than CTRL. FSHD scored lower than DMD for mental wellbeing domains. KEMVC associated with Physical-Function domain for BMD. Pain, Self-Efficacy and ADLs associated with QoL domains, with Fatigue the most consistently associated.

CONCLUSION

The present study identified differences between MD classifications within self-perceptions of mental-health. Muscle weakness is a defining feature of MD; however, it doesn't define QoL in adults with MD. A greater understanding of mental wellbeing, independence, and management of fatigue and pain, are required to improve QoL for adults with MD.

Frequency of reported pain in adult males with muscular dystrophy

INTRODUCTION

The purpose of this study was to present and compare pain between adult males with Duchenne (DMD), Becker's (BMD), Limb-Girdle (LGMD) Facioscapulohumeral (FSHD) forms of Muscular Dystrophy (MD), and healthy controls (CTRL), using three different methods of assessment.

METHODS

Pain was assessed using 1) a whole body visual analogue scale (VAS) of pain, 2) a generalised body map and 3) a localised body map.

RESULTS

All types of MD reported more VAS pain than CTRL, with 97% of all MD participants reporting pain; however, no differences were reported between types of MD. The generalised body map approach identified more frequent pain in the shoulders of FSHD (93%) than other groups (13-43%), hips of DMD (87%) and LGMD (75%) than other groups (0-29%), and legs of all MD (64-78%) than CTRL (25%). The localised body map approach identified common areas of frequent pain across types of MD, posterior distal leg and distal back, as well as condition specific regions of frequent pain, for example posterior trapezius in FSHD, and anterior hip pain in DMD and LGMD.

CONCLUSIONS

Using a single pain value (VAS), increased pain was reported by adults with MD compared to CTRL, with no clear differences between different MD groups, suggesting pain is symptomatic of MD. The use of the generalised body map approach, and to an even greater extent the localised body map approach, identified specific areas of frequent pain relevant to each individual condition. These results indicate that whist the commonly used generalised approach can be used to identify broad anatomical regions, the localised approach provides a more comprehensive understanding of pain, reflective of clinical assessment, and should be utilised in future research.

A family-based study into penetrance in facioscapulohumeral muscular dystrophy type 1

OBJECTIVE

An observational cross-sectional study was conducted in a national facioscapulohumeral muscular dystrophy (FSHD) expertise center to estimate the penetrance of FSHD1 and to evaluate phenotype-genotype correlations.

METHODS

Ten FSHD1 probands carrying 4-9 D4Z4 unit alleles and 140 relatives were examined. All 150 participants were genetically characterized, including D4Z4 methylation levels in the mutation carriers. Mutation carriers were classified as (1) symptomatic: with symptoms of muscle weakness on history and muscle FSHD signs on examination; (2) asymptomatic: without symptoms of muscle weakness but with muscle FSHD signs on examination; and (3) nonpenetrant: without symptoms of muscle weakness on history and without muscle FSHD signs on examination. We assessed the relationship between age-corrected clinical severity score and repeat size, sex, and D4Z4 methylation levels.

RESULTS

The maximum likelihood estimates of symptomatic and those of symptomatic plus asymptomatic FSHD showed that penetrance depends on repeat size and increases until late adulthood. We observed many asymptomatic carriers with subtle facial weakness with or without mild shoulder girdle weakness (25% [17/69]). Nonpenetrance was observed less frequently than in recent population studies (17% [12/69]), and most asymptomatic patients reported some shoulder pain. D4Z4 methylation tended to be lower in moderately to severely affected mutation carriers with 7 or 9 repeats.

DISCUSSION

This family-based study detected a lower overall nonpenetrance than previously observed, probably due to many asymptomatic mutation carriers identified by careful examination of facial and shoulder muscles. The recognition of asymptomatic mutation carriers is essential for selection of participants for future trials, and the likelihood estimates are helpful in counseling.

Chronic pain has a strong impact on quality of life in facioscapulohumeral muscular dystrophy

Introduction

Earlier small case series and clinical observations reported on chronic pain playing an important role in facioscapulohumeral dystrophy (FSHD). The aim of this study was to determine the characteristics and impact of pain on quality of life (QoL) in patients with FSHD.

Methods

We analyzed patient reported outcome measures collected through the U.K. FSHD Patient Registry.

Results

Of 398 patients, 88.6% reported pain at the time of study. The most frequent locations were shoulders and lower back. A total of 203 participants reported chronic pain, 30.4% of them as severe. The overall disease impact on QoL was significantly higher in patients with early onset and long disease duration. Chronic pain had a negative impact on all Individualised Neuromuscular Quality of Life Questionnaire domains and overall disease score.

Discussion

Our study shows that pain in FSHD type 1 (FSHD1) is frequent and strongly impacts on QoL, similar to other chronic, painful disorders. Management of pain should be considered when treating FSHD1 patients. Muscle Nerve57: 380–387, 2018

Facioscapulohumeral distrophy and physiotherapy: a literary review

[Purpose] The purpose of this review was to critically evaluate the literature concerning the physiotherapy of facioscapulohumeral dystrophy, and to determine an effective protocol for physiotherapy treatments, which can be adapted to patient characteristics. [Methods] A bibliographic research was carried out of research papers held in the following databases: PUBMED, PEDRO, MEDLINE, EDS BASE INDEX. The inclusion criteria for acceptance of the studies to the review were randomized controlled trials (RCTs) concerning a sample no smaller than 10 people and a medium- or long-term report of the results achieved. [Results] Just six of the works satisfied the inclusion criteria, and just three of them were useful for the review. However, these studies were difficult to compare. [Conclusion] At present, there are few studies concerning facioscapulohumeral dystrophy in the literature, and the few that are available rule out the utility of the techniques used. Therefore, more RCTs of new treatment strategies are needed.

Myositis mimics: how to recognize them

PURPOSE OF REVIEW

To help clinicians to distinguish between myositis (and other immune-mediated and immunosuppressant-responsive disorders) and its many clinical mimics.

RECENT FINDINGS

Increasing experience has shown that findings from conventional investigations, such as muscle biopsy, can be misleading. More specialist investigations, notably autoantibody screening, immunocytochemical techniques, and evolving DNA technologies, are powerful tools but experience is currently largely limited to specialist centres - and even these techniques are open to misinterpretation.

SUMMARY

Misdiagnosis is hazardous to the patient. Treatable conditions may be missed, or patients subjected inappropriately to potentially toxic drug treatments. Judicious use of clinical skills alone should help reduce these risks.

Pain location and intensity impacts function in persons with myotonic dystrophy type 1 and facioscapulohumeral dystrophy with chronic pain

INTRODUCTION

We examined the effects of pain site and intensity on function in patients with myotonic dystrophy type 1 (DM1) and facioscapulohumeral muscular dystrophy (FSHD) and chronic pain.

METHODS

Questionnaires assessing pain sites, pain extent (number of sites), pain intensity, and pain interference were completed by 182 individuals with DM1 (43%) or FSHD (57%) and chronic pain.

RESULTS

There was a positive association between pain extent and intensity with pain interference, and a negative association with psychological functioning in both DM1 and FSHD. Pain intensity at specific sites had differential impact beyond the effects of pain intensity alone. Head pain intensity independently affected psychological functioning, whereas leg, foot, hip, and knee pain contributed independently to the prediction of pain interference.

CONCLUSIONS

Pain site and intensity differentially modulates the effect of chronic pain on function in DM1 and FSHD patients. Researchers and clinicians should consider these factors when assessing and treating pain.

Longitudinal features of STIR bright signal in FSHD

INTRODUCTION

Magnetic resonance imaging of muscle shows short tau-inversion recovery (STIR) brightness in autosomal dominant facioscapulohumeral muscular dystrophy (FSHD1) suggestive of active inflammation/injury. We measured the longitudinal stability/progression of this potential disease biomarker.

METHODS

Nine subjects underwent calf MRI imaging over 2 years. Two radiologists evaluated qualitative muscle changes.

RESULTS

In 3/9 subjects, calf muscles demonstrated moderate/severe STIR hyperintensity at Time 1 that had progressed to fatty replacement 2 years later (Time 2). In the remaining subjects, moderate/severe muscle STIR abnormalities, when present, were consistent between exams. Mild STIR+ elevations had roughly similar patterns between exams.

CONCLUSIONS

Moderate/severe STIR hyperintensities often foreshadow fatty replacement over a 2-year interval. Whether longer time courses are required to observe muscle degeneration and fatty replacement in some subjects remains to be explored.

Symptom burden in persons with myotonic and facioscapulohumeral muscular dystrophy

OBJECTIVE

This study examines the prevalence of pain, fatigue, imbalance, memory impairment, and vision loss in persons with myotonic and facioscapulohumeral dystrophy and their association with functioning.

DESIGN

A survey (N = 170) included measures of severity (0-10 scales) and course of these symptoms as well as measures of social integration, home competency, mental health, and productive activity. Descriptive and regression analyses examined the associations between symptoms and functioning.

RESULTS

Fatigue (91%), imbalance (82%), and pain (77%) were the most commonly reported. The most severe symptom was fatigue (mean ± SD severity, 5.14 ± 2.81), followed by imbalance (4.95 ± 3.25). Symptoms were most likely to stay the same or worsen since onset. Controlling for potential medical and demographic confounds, symptoms were associated with 17% of the mental health variance, 10% of home competency, 10% of social integration, 16% of productive activity for myotonic dystrophy type 1, and 12% of productive activity for facioscapulohumeral muscular dystrophy.

CONCLUSIONS

Pain, fatigue, and imbalance are common in persons with muscular dystrophy. Interventions may be useful to mitigate their impact on functioning. Further research should examine these relationships to guide clinical practices.

Facioscapulohumeral muscular dystrophy and Charcot-Marie-Tooth neuropathy 1A - evidence for "double trouble" overlapping syndromes

BACKGROUND

We report on a patient with genetically confirmed overlapping diagnoses of CMT1A and FSHD. This case adds to the increasing number of unique patients presenting with atypical phenotypes, particularly in FSHD. Even if a mutation in one disease gene has been found, further genetic testing might be warranted in cases with unusual clinical presentation.

CASE PRESENTATION

The reported 53 years old male patient suffered from walking difficulties and foot deformities first noticed at age 20. Later on, he developed scapuloperoneal and truncal muscle weakness, along with atrophy of the intrinsic hand and foot muscles, pes cavus, claw toes and a distal symmetric hypoesthesia. Motor nerve conduction velocities were reduced to 20 m/s in the upper extremities, and not educible in the lower extremities, sensory nerve conduction velocities were not attainable. Electromyography showed both, myopathic and neurogenic changes. A muscle biopsy taken from the tibialis anterior muscle showed a mild myopathy with some neurogenic findings and hypertrophic type 1 fibers. Whole-body muscle MRI revealed severe changes in the lower leg muscles, tibialis anterior and gastrocnemius muscles were highly replaced by fatty tissue. Additionally, fatty degeneration of shoulder girdle and straight back muscles, and atrophy of dorsal upper leg muscles were seen. Taken together, the presenting features suggested both, a neuropathy and a myopathy. Patient's family history suggested an autosomal dominant inheritance.Molecular testing revealed both, a hereditary motor and sensory neuropathy type 1A (HMSN1A, also called Charcot-Marie-Tooth neuropathy 1A, CMT1A) due to a PMP22 gene duplication and facioscapulohumeral muscular dystrophy (FSHD) due to a partial deletion of the D4Z4 locus (19 kb).

CONCLUSION

Molecular testing in hereditary neuromuscular disorders has led to the identification of an increasing number of atypical phenotypes. Nevertheless, finding the right diagnosis is crucial for the patient in order to obtain adequate medical care and appropriate genetic counseling, especially in the background of arising curative therapies.

Focal and other unusual presentations of facioscapulohumeral muscular dystrophy

INTRODUCTION

Facioscapulohumeral dystrophy (FSHD) presents classically with facial and shoulder-girdle weakness. We report focal atypical presentations of FSHD. Our aim was to identify focal/unusual phenotypes in genetically confirmed FSHD cases.

METHODS

We undertook a retrospective review of an academic center database of the period from 1996 to 2011. Of 139 FSHD cases, 7 had atypical genetically confirmed disease. Clinical data were abstracted.

RESULTS

Seven cases (4 men) had a mean age of 37 years at onset (range 18-63 years) and mean 43 years at diagnosis (range 20-74 years). Presenting symptoms were monomelic lower limb (n = 3) or upper limb (n = 2) atrophy, or axial weakness (n = 2). Five patients had focal weakness on examination. CK was normal to borderline high. Two patients had a relative with FSHD. Coexistent unusual features included dyspnea (n = 1), S1 radicular pain with calf atrophy (n = 2), and peripheral neuropathy (n = 1). Almost all patients had myopathic EMG changes. DNA analysis showed a D4Z4 EcoRI fragment size ranging from 20 to 37 kilobases.

CONCLUSIONS

FSHD may present with focal weakness, dyspnea and myopathic EMG changes. These findings should raise the possibility of FSHD.

Chronic pain in neuromuscular disease: pain site and intensity differentially impacts function

The importance of pain extent (ie, number of body areas with pain) and pain site as factors contributing to dysfunction in persons with chronic, slowly progressive neuromuscular disease (NMD), remains poorly understood. This article discusses the importance of assessing pain site in addition to global pain intensity in patients with chronic, slowly progressive NMD. The importance of addressing pain at multiple sites will have a major impact on future studies assessing interventions to treat pain in this patient population.

Recommendations for the management of facioscapulohumeral muscular dystrophy in 2011

Facioscapulohumeral muscular dystrophy (FSHD) is a neuromuscular disease, characterized by an autosomal dominant mode of inheritance, facial involvement, and selectivity and asymmetry of muscle involvement. In general, FSHD typically presents before age 20 years. Usually, FSHD muscle involvement starts in the face and then progresses to the shoulder girdle, the humeral muscles and the abdominal muscles, and then the anterolateral compartment of the leg. Disease severity is highly variable and progression is very slow. About 20% of FSHD patients become wheelchair-bound. Lifespan is not shortened. The diagnosis of FSHD is based on a genetic test by which a deletion of 3.3kb DNA repeats (named D4Z4 and mapping to the subtelomeric region of chromosome 4q35) is identified. The progressive pattern of FSHD requires that the severity of symptoms as well as their physical, social and psychological impact be evaluated on a regular basis. A yearly assessment is recommended. Multidisciplinary management of FSHD--consisting of a combination of genetic counselling, functional assessment, an assessment by a physical therapist, prescription of symptomatic therapies and prevention of known complications of this disease--is required. Prescription of physical therapy sessions and orthopedic appliances are to be adapted to the patient's deficiencies and contractures.

Changes in pain-related beliefs, coping, and catastrophizing predict changes in pain intensity, pain interference, and psychological functioning in individuals with myotonic muscular dystrophy and facioscapulohumeral dystrophy

OBJECTIVES

The primary aim of this study was to test hypothesized associations between changes in psychological variables (ie, pain beliefs, catastrophizing, and coping strategies) and changes in pain intensity and related adjustment (ie, pain interference and psychological functioning) in individuals with myotonic muscular dystrophy (MMD) and facioscapulohumeral muscular dystrophy (FSHD).

METHODS

A sample of 107 adults with a diagnosis of MMD or FSHD, reporting pain in the past 3 months, completed assessments at 2 time points, separated by approximately 24 months.

RESULTS

Results showed that changes in pain-related psychological variables were significantly associated with changes in psychological functioning, pain intensity, and pain interference. Specifically, increases in the belief that emotion influences pain, and catastrophizing were associated with decreases in psychological functioning. Increases in the coping strategies of asking for assistance and resting, and the increases of catastrophizing were associated with increases in pain intensity. Finally, increases in pain intensity and asking for assistance were associated with increases in pain interference.

DISCUSSION

The results support the use of the biopsychosocial model of pain for understanding pain and its impact in individuals with MMD or FSHD. These findings may inform the design and implementation of psychosocial pain treatments for people with muscular dystrophy and chronic pain.

[Facioscapulohumeral muscular dystrophy. Clinical picture, atypical forms, diagnostics, genetics]

The classic phenotype of the facioscapulohumeral muscular dystrophy (FSHD) includes an initially restricted pattern of asymmetric weakness of facial and shoulder girdle muscles. Disease progression is usually slow and typically accompanied by foot extensor muscle weakness and pelvic girdle weakness. Atypical patterns of FSHD that include isolated camptocormia and facial muscle sparing exceed current diagnostic criteria. No causal genetic lesion in FSHD has been identified yet. In the vast majority of cases, FSHD results from a heterozygous partial deletion of a critical number of repetitive elements (D4Z4) on chromosome 4q35 (4qA allele). Molecular diagnostic testing is appropriate to confirm the diagnosis of FSHD without need for muscle biopsy. Penetrance of this dominantly inherited disorder is high, exhibiting a great phenotypic variability in clinical pattern and disease progression even among affected members of the same family.

Consensus statement on standard of care for congenital myopathies

Recent progress in scientific research has facilitated accurate genetic and neuropathological diagnosis of congenital myopathies. However, given their relatively low incidence, congenital myopathies remain unfamiliar to the majority of care providers, and the levels of patient care are extremely variable. This consensus statement aims to provide care guidelines for congenital myopathies. The International Standard of Care Committee for Congenital Myopathies worked through frequent e-mail correspondences, periodic conference calls, 2 rounds of online surveys, and a 3-day workshop to achieve a consensus for diagnostic and clinical care recommendations. The committee includes 59 members from 10 medical disciplines. They are organized into 5 working groups: genetics/diagnosis, neurology, pulmonology, gastroenterology/nutrition/speech/oral care, and orthopedics/rehabilitation. In each care area the authors summarize the committee's recommendations for symptom assessments and therapeutic interventions. It is the committee's goal that through these recommendations, patients with congenital myopathies will receive optimal care and improve their disease outcome.

Clinical study of chronic pain in hereditary myopathies

In the field of neuromuscular diseases, pain and its management remain imperfectly understood and described. We study 68 unselected, consecutive adult patients attending a multidisciplinary consultation for hereditary myopathy. Forty-six (67%) were suffering from chronic pain. Pain was assessed with self report questionnaire and a standardized clinical evaluation. Mean duration of the pain was 7.2+/-8.9 years, and multiple body sites were involved in 91% of cases. Usual pain intensity (Visual Analogue Scale 0-100) was moderate (39.5+/-26.2). For 42 patients (91%) the principal cause of the pain was of muscular origin, with frequent features of myofascial pain syndromes (MPS, 50%) and fibromyalgia (FMS, 26%). Pain was the major complaint for 6.3% of the patients. Pain management was essentially based on physiotherapy. Only a minority of patients (38%) has an appropriate drug treatment. Common analgesics appeared to be very effective in these patients.

Control of the upper body movements during level walking in patients with facioscapulohumeral dystrophy

Facioscapulohumeral dystrophy (FSHD) is a muscular disease usually spreading from upper to lower body and characterised by asymmetric muscle weakness. Walking ability is compromised in these patients, with a consequent high risk of falls. A quantitative analysis of the upper body oscillations may unveil useful information about the capacity of these patients to stabilise the head, maintain balance, and compensate for lower limb muscle weakness during walking. This study involved 13 patients with FSHD and 13 healthy volunteers. The trajectories of three points located on the cranio-caudal axis, at head, shoulder, and pelvis levels, during level walking, were analysed. The range of motion of these three points and the attenuation of the relevant accelerations going from pelvis to head level were used to describe the upper body movements during walking. The patients had wider and less symmetrical oscillations than the healthy controls both in antero-posterior and medio-lateral directions. Furthermore, the capacity of the patients to attenuate the accelerations going from pelvis to head level was reduced. These features may be related not only to upper body muscle weakness, but also to a strategy functional to the compensation of proximal leg muscle weakness. In conclusion, this study highlighted that the control of upper body oscillations and of head stability is reduced in patients with FSHD, suggesting that the assessment of the upper body movements should be included in the treatment decision process.

Quality of life and pain in patients with facioscapulohumeral muscular dystrophy

The aim of this study was to assess quality of life (QoL) and evaluate the occurrence and characteristics of pain in facioscapulohumeral muscular dystrophy (FSHD) patients. No study has yet assessed QoL in a large group of FSHD patients and, overall, few studies have assessed pain in neuromuscular diseases. We performed a prospective study using a multidimensional protocol including: clinical (according to the Clinical Severity Scale Rev1); genetic (p13E-11 EcoRI fragments Rev1); QoL (Short Form-36); pain (Visual Analog Scale and Portenoy-6 questions); and depression (Beck Depression Inventory) assessment. QoL measures of FSHD were compared with those of Italian norms. Moreover, we correlated QoL and pain measurements with clinical findings. Sixty-five patients were enrolled in the study. QoL was statistically significantly reduced with respect to the Italian normative sample, mainly in physical domains. Our study demonstrated that pain is frequent in FSHD patients. More than half of the patients complained of at least moderate pain. Women complained of slightly higher levels of deterioration in the emotional aspects of QoL than men. Clinical pattern (as assessed by Clinical Severity Scale) was closely related to physical QoL domains: the higher the clinical involvement, the more severe the QoL deterioration. This study provided information that may be crucial in clinical practice: pain may be a relevant aspect in FSHD patients, and prevention strategies or relevant therapies should be considered as appropriate. Moreover, we must pay more attention to gender differences: women can suffer far greater deterioration in the emotional aspects of QoL. Further multidimensional observations are needed. Muscle Nerve 40: 200-205, 2009.

Impact of biopsychosocial factors on chronic pain in persons with myotonic and facioscapulohumeral muscular dystrophy

To assess the role of biopsychosocial factors in patients with type 1 myotonic and facioscapulohumeral muscular dystrophy (MMD1/FSHD) with chronic pain. Associations between psychosocial factors were found to be important in other samples of persons with pain and both psychological functioning and pain interference in a sample of patients suffering from MMD/FSHD. Prospective, multiple group, survey study of 182 patients with confirmed MMD1 and FSHD. Participants completed surveys assessing pain interference and psychological functioning, as well as psychosocial, demographic, and injury-related variables. Analyses indicated that greater catastrophizing was associated with increased pain interference and poorer psychological functioning, pain attitudes were significantly related to both pain interference and psychological functioning, and coping responses were significantly related only to pain interference. In addition, greater perceived social support was associated with better psychological functioning. The results support the use of studying pain in persons with MMD/FSHD from a biopsychosocial perspective, and the importance of identifying psychosocial factors that may play a role in the adjustment to and response to pain secondary to MMD/FSHD.

Facioscapulohumeral muscular dystrophy

Facioscapulohumeral muscular dystrophy (FSHD), a dominantly inherited disorder, is the third most common dystrophy after Duchenne and myotonic muscular dystrophy. No known effective treatments exist for FSHD. The lack of an understanding of the underlying pathophysiology remains an obstacle in the development of targeted therapeutic interventions. The genetic defect is a loss of a critical number of a repetitive element (D4Z4) in the 4q subtelomeric region. The loss of the repeats results in specific changes in chromatin structure, although neither the molecular nor the cellular consequences of this change are known. Nevertheless, these epigenetic changes in chromatin structure offer a potential therapeutic target. This review discusses current management strategies in FSHD as well as potential therapeutic interventions to slow down or reverse the progressive muscle atrophy and weakness.

Novel mitochondrial tRNA Leu(CUN) transition and D4Z4 partial deletion in a patient with a facioscapulohumeral phenotype

Point mutations in mtDNA-encoded tRNA genes frequently cause isolated myopathies but rarely cause the facioscapulohumeral phenotype. We report on a patient affected with chronic progressive weakness of facioscapulohumeral/peroneal muscles whose muscle biopsy showed a mitochondrial myopathy. mtDNA direct sequencing and RFLP analysis revealed a heteroplasmic transition T12313C which disrupts a conserved site in the T Psi C stem of the tRNA(Leu(CUN)) gene and fulfills the accepted criteria of pathogenicity. A partial deletion of the nuclear DNA D4Z4 region with residual repeat sizes of 25 kb was also found in the patient and in her mother. This is the first reported case of mitochondrial myopathy/facioscapulohumeral muscular dystrophy (FSHD) "double trouble".

Chronic pain in persons with myotonic dystrophy and facioscapulohumeral dystrophy

OBJECTIVE

To determine the nature and scope of pain in working-aged adults with myotonic muscular dystrophy (MMD) and facioscapulohumeral muscular dystrophy (FSHD).

DESIGN

Retrospective, cross-sectional survey.

SETTING

Community-based survey.

PARTICIPANTS

Convenience sample of subjects with MMD and FSHD.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Overall intensity and duration of pain, pain inference, pain sites, pain treatments, and relief provided by pain treatments.

RESULTS

More subjects with FSHD (82%) than with MMD (64%) reported pain. The most frequently reported pain sites for both diagnostic groups were lower back (66% MMD, 74% FSHD) and legs (60% MMD, 72% FSHD). Significant differences in pain intensity were found between the diagnostic groups in the hands, legs, knees, ankles, and feet, with patients with MMD reporting greater pain intensity at these sites than patients with FSHD. Age was related to the onset of pain (participants reporting pain were younger than those not reporting pain in the FSHD sample), but pain severity was not significantly associated with age in those reporting pain. Respondents with both diagnoses that reported mobility limitations and used assistive devices (eg, wheelchair, cane) reported more pain severity than those with mobility limitations who did not use assistive devices, who, in turn, reported more pain severity than respondents who reported no mobility limitations at all. The treatments that were reported to provide the greatest pain relief were not necessarily those that were the most frequently tried or still used.

CONCLUSIONS

The findings indicate that pain is a more common problem in persons with FSHD than in persons with MMD, although it is common in both populations. In addition, these pain problems are chronic, underscoring the need to identify and provide effective pain treatments for patients with these neuromuscular diseases.

Facioscapulohumeral dystrophy

Facioscapulohumeral dystrophy (FSHD) is the third most common inherited muscular dystrophy after Duchenne dystrophy and myotonic dystrophy. Over the last decade, major advances have occurred in the understanding of the genetics of this disorder. Despite these advances, the exact mechanisms that lead to atrophy and weakness secondary to the genetic defect are still not understood. The purposes of this article are to increase awareness of FSHD among clinicians; to provide an update regarding the genetics, clinical features, natural history, and current management of FSHD; and to discuss opportunities for research.

Pain in hereditary neuromuscular disorders and myasthenia gravis: a national survey of frequency, characteristics, and impact

The aim of our study was to evaluate pain frequency, intensity, and disability levels in a population with neuromuscular disorders (NMD). Of 862 questionnaires mailed to outpatients treated at 10 centers, 511 (300 men and 211 women) responded with answers suitable for analysis (response rate: 59.3%). Patients had Duchenne or Becker muscular dystrophy, type 1 myotonic muscular dystrophy, facioscapulohumeral muscular dystrophy, metabolic myopathy, or myasthenia gravis (MYA). The questionnaire packet included numeric scales for pain intensity and relief, the Brief Pain Inventory, the Saint Antoine Pain Questionnaire, and a scale to assess disability. More than two-thirds of the 331 patients (67.3%) suffered pain during the last three months. The mean number of days with pain was 18.4+/-15.1 days. The mean pain intensity was 4.8+/-2.5. Pain was usually diffuse (153 patients, 44%) and intermittent (228, 71%). Pain intensity varied by the NMD diagnosis; the most severe pain was observed in metabolic myopathy (13/27 patients suffered severe pain, 49%) and in MYA (16/42, 38%). Approximately three-quarters of patients had fewer than 10 days of inactivity due to pain during the last three months, and 98% had fewer than 30 days. Our study indicates that pain is frequent in hereditary muscle disorders and MYA. Mean intensity is moderate. Pain in NMD patients should be systematically assessed.

Sleep quality in Facioscapulohumeral muscular dystrophy

OBJECTIVE

To evaluate the subjective sleep quality, the prevalence of daytime sleepiness and the risk of sleep-related upper airways obstruction in patients with genetically proven Facioscapulohumeral muscular dystrophy (FSHD). FSHD is an autosomal dominant myopathy, characterized by an early involvement of facial and scapular muscles with eventual spreading to pelvic and lower limb muscles.

PATIENTS AND METHODS

Forty-six patients were enrolled, 27 women and 19 men, mean age 43.6+/-14.1 years. Study protocol included: a Clinical Severity Scale (CSS) for FSHD, Pittsburgh Sleep Quality Index (PSQI), Italian version of the Epworth Sleepiness Scale (ESS) and the search for clinical predictors of sleep-related airways obstruction.

RESULTS

Twenty-seven patients presented snoring, 12 reported respiratory pauses during sleep. One half (23/46) had PSQI scores above the normal threshold (=5). Correlations were found between the CSS and: the total PSQI score, the components C1 sleep quality, C5 sleep disturbances, C7 daytime dysfunction.

CONCLUSION

Our data support the hypothesis that patients with FSHD have an impaired sleep quality, and that this impairment is directly related to the severity of the disease. A systematic polysomnographic evaluation of these patients will be necessary to confirm the presence of sleep disruption and to clarify its pathogenesis.

Effects of training and albuterol on pain and fatigue in facioscapulohumeral muscular dystrophy

Background

We recently reported a randomised controlled trial on the efficacy of strength training and the β 2-adrenergic agonist albuterol in patients with facioscapulohumeral muscular dystrophy (FSHD). Strength training and albuterol appeared safe interventions with limited positive effect on muscle strength and volume. We concurrently explored the prevalence and the characteristics of pain and fatigue in the participating FSHD patients, because these are probably underreported but clinically relevant symptoms in this disorder. Next, we studied the effects of albuterol and strength training on pain, experienced fatigue, healthrelated functional status and psychological distress.

Methods

Sixty-five patients were randomised to strength training of elbow flexors and ankle dorsiflexors or nontraining. After 26 weeks, albuterol (sustained-release, 8 mg bid) was added in a randomised, doubleblind, placebo-controlled design. Outcomes comprised self-reported pain, experienced fatigue, functional status and psychological distress obtained with validated questionnaires at 52 weeks.

Results

Eighty percent of patients reported chronic persistent or periodic, multifocal pains. Thirtyfour percent of the participants were severely fatigued. Strength training and albuterol failed to have a significant effect on all outcomes.

Conclusions

Pain and fatigue are important features in FSHD. Strength training and albuterol do not have a positive or negative effect on pain, experienced fatigue, functional status and psychological distress.

Experienced and physiological fatigue in neuromuscular disorders

OBJECTIVE

Fatigue has been described as a typical symptom of neurological diseases. It might be caused both by changes at the peripheral and at the central level. This study measured the level of experienced fatigue and physiological correlates of fatigue in three genetically defined neuromuscular disorders.

METHODS

Sixty-five facioscapulohumeral dystrophy (FSHD), 79 classical myotonic dystrophy (DM), 73 hereditary motor and sensory neuropathy type I (HMSN) patients and 24 age-matched healthy controls made a 2-min sustained maximal voluntary contraction of the biceps brachii muscle. Experienced fatigue at the current moment was assessed with the abbreviated fatigue questionnaire just before the physiological measurement. Peripheral fatigue was quantified by comparing the amplitudes of an initial and a final stimulated force response during rest. Muscle fibre conduction velocity was determined from a 5-channel surface EMG recording in order to show peripheral changes during the contraction. Central aspects of fatigue were measured using superimposed electrical endplate stimulation.

RESULTS

Patients showed an increased level of experienced fatigue. Total physiological and peripheral fatigue were smaller in patients compared to controls, and central fatigue was normal. The most interesting result of this study was the presence of a large central activation failure (CAF) in all groups of neuromuscular patients; they showed CAF values of 36-41% already directly at the start of sustained contraction, whereas the control group showed only 12%. CAF slightly correlated with the level of experienced fatigue just before the test.

CONCLUSIONS

The cause of the large CAF in patients is unclear. Reduced concentration, motivation or effort can lead to lower central activation. In neuromuscular patients especially fear of physical activity or fear to damage the muscle or nerve tissue may contribute. Besides, also physiological feedback mechanisms or changes at the motocortical level may be a cause of reduced central activation.

SIGNIFICANCE

For the clinician it is important to know that experienced fatigue is part of the clinical spectrum of neuromuscular patients. Besides, the weakness in these patients is aggravated by reduced central activation. Potentially, both problems could be subject of an intervention.

Muscle pain in myophosphorylase deficiency (McArdle’s disease): The role of gender, genotype, and pain-related coping

Pain characteristics were examined in 24 patients with myophosphorylase deficiency (McArdle's disease). Pain parameters were related to mutation analyses as well as psychosocial data using a pain questionnaire including an assessment of psychosocial distress and coping measures (Beck Depression Inventory BDI; Kiel Pain Inventory KPI, Multidimensional Fatique Inventory MFI). Twenty-three patients complained of pain, which was intermittent and exercise-induced in 15 patients. Eight patients complained of permanent pain, which was superimposed by exercise-induced pain in 7 patients. Patients reported 3-7 different pain characters and various localisations. Patients with permanent pain were significantly more frequently female, experienced higher impact on general activities and sleep as well as higher scores on the MFI. Furthermore, these patients revealed higher scores regarding several psychosocial risk factors including avoidance behavior whereas patients with intermittent pain predominantly showed endurance coping. There was no correlation between age or disease duration, pain intensity as well as mutation type and development of permanent or intermittent pain. In addition, severity of the clinical phenotype did not correlate with ACE polymorphism. Although McArdle's disease is a muscle glycogenosis with marked biochemical homogeneity, the clinical presentation can be quite heterogeneous. A substantial number of patients revealed permanent pain as a major clinical symptom. As permanent pain is not related to age or disease duration, it might be a clinically important subgroup of McArdle's disease. Gender-related genetic factors as well as maladaptive pain-related coping may contribute to the development of such a chronic pain symptom.

Pain and neuromuscular disease: the results of a survey

OBJECTIVE

The objective of this study was to evaluate pain frequency, severity, location, treatment, and relief in a population of adult patients with neuromuscular disorders (NMD).

DESIGN

The authors used a self-completion mail questionnaire from the Physical Medicine Clinic at the Lille University Medical Center (northern France). Two hundred eighty-one adults with a confirmed diagnosis of hereditary neuromuscular disease were mailed a questionnaire, which was returned by 125 subjects (response rate = 45%). The main outcome measures were mean motor deficiency scores (on the Brooke and Vignos scales), anxiety and depression scores, pain intensity (on a 0-10 numeric scale) and location, frequency of pain-aggravating situations, and pain treatment and relief.

RESULTS

Seventy-three percent of respondents reported pain and 62% reported chronic pain (defined as pain for at least 3 mos). The mean pain intensity was 6.1/10 with 40% reporting severe pain (a score of > or = 7). Forty-six percent and 16% of subjects had a high risk for anxiety and depression, respectively. The most common pain-aggravating situations were "walking," "standing," and "muscle stretching." Walking was more frequently cited as a pain-aggravating situation by the chronic pain population than by the acute pain population. Seventy percent of patients with pain had received at least one analgesic drug. Massage was the most frequently prescribed physical treatment.

CONCLUSIONS

Pain is a frequent symptom in adult patients with NMD and needs to be better characterized in this population. The use of painkillers and physical pain treatments did not seem to provide adequate relief for the patients studied here.

Facioscapulohumeral muscular dystrophy

Facioscapulohumeral muscular dystrophy (FSHD) is a dominantly inherited disorder with an initially restricted pattern of weakness. Early involvement of the facial and scapular stabilizer muscles results in a distinctive clinical presentation. Progression is descending, with subsequent involvement of either the distal anterior leg or hip-girdle muscles. There is wide variability in age at onset, disease severity, and side-to-side symmetry, which is evident even within affected members of the same family. Although FSHD is considered a relatively benign dystrophy by some, as many as 20% of patients eventually become wheelchair-bound. Associated nonskeletal muscle manifestations include high-frequency hearing loss as well as retinal telangiectasias, both of which are rarely symptomatic. The causal genetic lesion in FSHD was described over a decade ago, raising hope that knowledge about its molecular and cellular pathophysiology was soon to follow. In the vast majority of cases, FSHD results from a heterozygous partial deletion of a critical number of repetitive elements (D4Z4) on chromosome 4q35; yet, to date, no causal gene has been identified. The accumulating evidence points to a complex, perhaps unique, molecular genetic mechanism. The absence of detectable expressed sequences from D4Z4, the association of FSHD-causing 4q35 deletions with a specific distal genomic sequence (4qA allele), altered DNA methylation patterns on 4q35, as well as other direct and indirect evidence point to epigenetic mechanisms. As a consequence, partial deletion of D4Z4 results in a (local) chromatin change and ultimately results in the loss of appropriate control of gene expression. There is at present no effective treatment for FSHD. A better understanding of the underlying pathophysiology is needed to design targeted interventions. Despite these limitations, however, two randomized controlled clinical trials have been conducted on FSHD. These trials, along with a previous natural history study, have helped to better define outcome measures for future trials in FSHD as well as other dystrophies.

Chronic Pain in Persons With Neuromuscular Disease

OBJECTIVE

To examine the nature and scope of pain in persons with neuromuscular disorder (NMD).

DESIGN

Survey study.

SETTING

University-based rehabilitation research programs.

PARTICIPANTS

Adults with NMD (N=193).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Pain presence or absence, pain severity, pain quality (Neuropathic Pain Scale), pain interference (Brief Pain Inventory), pain site, quality of life (Medical Outcomes Study 36-Item Short-Form Health Survey [SF-36]), and pain treatment.

RESULTS

Seventy-three percent of the sample reported pain, with 27% of these reporting that this pain was severe (> or =7 on a 0-10 scale), on average. "Deep," "tiring," "sharp," and "dull" were the words used most frequently to describe NMD pain. Patients with amyotrophic lateral sclerosis and myotonic muscular dystrophies reported the greatest pain interference, and patients with Charcot-Marie-Tooth the least, among all NMD diagnoses. The most frequent pain site, overall, was back (49%), followed by leg (47%), shoulder (43%), neck (40%), buttock and hip(s) (37%), feet (36%), arm(s) (36%), and hand(s) (35%). The study participants reported significantly greater dysfunction than subjects in the SF-36 normative sample (persons without health problems) on a number of the SF-36 scales. However, we found no significant differences between the study participants and the US norms on the SF-36 role-emotional or mental health scales. A number of pain treatments were used by the study sample, but no treatment appeared to be effective for all participants, and some of the treatments reported as most effective (eg, chiropractic care) were used by very few participants.

CONCLUSIONS

Pain is a common problem among patients with NMDs. There are many similarities, but also some important differences, between NMD diagnostic groups on the nature and scope of pain and its impact. More research is needed to identify and test effective treatments for NMD-related pain.

Practical considerations in the assessment and treatment of pain in adults with physical disabilities

Adults aging with physical disabilities experience a variety of pain disorders that affect their functionality and QOL. It is important that clinicians caring for this population be knowledgeable about this common symptom and be able to perform a thorough history and physical examination. In addition, it is imperative to have a good working knowledge of the strengths and limitations of the treatments available.

Chronic pain secondary to disability: a review

BACKGROUND

Until recently, very little has been written regarding chronic pain as a secondary problem in persons who already have a physical disability, despite the potential for pain to increase the negative impact of what may already be a very disabling condition. The purpose of this review is to summarize what is currently known concerning the nature and scope of chronic pain as a secondary condition to disability, specifically spinal cord injury, acquired amputations, cerebral palsy, multiple sclerosis, neuromuscular disease, and postpolio syndrome.

METHOD

What is known concerning the frequency, severity, impact, and treatment of pain in these specific conditions is reviewed, as are the factors that contribute to, or are associated with, adjustment to chronic pain in these disability groups. The authors conclude with several research questions that emerge from this knowledge, the answers to which will contribute to the long-term goal of the reduction of pain and suffering in persons with disabilities.

CONCLUSIONS

The existing literature clearly documents that many persons with disabilities experience chronic pain. Many questions remain unanswered regarding the scope, severity, and treatment of chronic pain in these groups.