George H. Kraft

Magnetic Resonance Imaging Signal Changes in Denervated Muscles after Peripheral Nerve Injury

The evaluation of peripheral nerve disorders has traditionally relied on a clinical history, physical examination, and electrodiagnostic studies. Recent studies have used magnetic resonance imaging (MRI) to evaluate a variety of both nerve and muscle disorders. In this article, we describe the use of MRI, using short-tau inversion recovery (STIR) sequences, to evaluate muscle signal characteristics in a variety of peripheral nerve disorders. A total of 32 patients were studied, and 12 representative cases are discussed in detail. Increased STIR signal in muscle was seen in cases of severe axonotmetic injuries involving the transection of axons producing severe denervation changes on electromyography. The increased STIR signal in denervated muscles was seen as early as 4 days after the onset of clinical symptoms, which is significantly earlier than changes detected on electromyography. The MRI signal changes were reversible when the recovery of motor function occurred as a result of further muscle innervation. In cases of neurapraxic nerve injuries, characterized by conduction block without axonal loss, the STIR signal in muscle was normal. These findings show that MRI using STIR sequences provides a panoramic visual representation of denervated muscles useful in localizing and grading the severity of peripheral nerve injury secondary to either disease or trauma. MRI using STIR sequences may therefore play an important role in the prediction of clinical outcome and the formulation of appropriate therapy early after peripheral nerve injury.

Chronic pain in a large community sample of persons with multiple sclerosis.

Introduction: This study examined the prevalence, intensity, interference, and biopsychosocial correlates of pain in a large community-based sample of persons with multiple sclerosis (MS). Methods: Mail surveys were returned by 442 members of the King C ounty (WA) MS Association. Average pain intensity, pain-related activity interference, depressive symptoms and severity of MS were assessed. Results: Forty-four percent reported persistent, bothersome pain in the three months prior to completing the survey. Participants with pain reported an average pain intensity rating of 5.2 (SD =2.3) on the 0 (no pain) to 10 (pain as bad as could be) scale. Twenty-seven percent reported severe pain (score of 7-10), while 51% of those with pain rated the interference of their pain with daily activities as none to minimal. Twenty percent reported severe interference in activities as a result of pain. In multivariate modeling, MS illness severity, marital status, and self-ratings of overall health were significantly associated with pain-related interference with activities. Conclusions: A pproximately a fourth of this sample described having a chronic pain problem characterized by severe pain intensity and significant pain-related interference with activities. Disability due to pain may be more important than previously recognized for the MS population.

Falls in Multiple Sclerosis

To examine incidence, associated factors, and health care provider (HCP) response to falls in persons with multiple sclerosis (MS).

Proteolipid protein is necessary in peripheral as well as central myelin

Alternative products of the proteolipid protein gene (PLP), proteolipid protein (PLP) and DM20, are major components of compact myelin in the central nervous system, but quantitatively minor constituents of Schwann cells. A family with a null allele of PLP has a less severe CNS phenotype than those with other types of PLP mutations. Moreover, individuals with PLP null mutations have a demyelinating peripheral neuropathy, not seen with other PLP mutations of humans or animals. Direct analysis of normal peripheral nerve demonstrates that PLP is localized to compact myelin. This and the clinical and pathologic observations of the PLP null phenotype indicate that PLP/DM20 is necessary for proper myelin function both in the central and peripheral nervous systems.

MR nerve imaging in a prospective cohort of patients with suspected carpal tunnel syndrome

Objectives To evaluate the reliability and diagnostic accuracy of high-resolution MRI of the median nerve in a prospectively assembled cohort of subjects with clinically suspected carpal tunnel syndrome (CTS). Methods The authors prospectively identified 120 subjects with clinically suspected CTS from five Seattle-area clinics. All subjects completed a hand-pain diagram and underwent a standardized nerve conduction study (NCS). The reference standard for determining CTS status was a classic or probable hand pain diagram and NCS with a difference >0.3 ms between the 8-cm median and ulnar peak latencies. Readers graded multiple imaging parameters of the MRI on four-point scales. The authors also performed quantitative measurements of both the median nerve and carpal tunnel cross-sectional areas. NCS and MRI were interpreted without knowledge of the other study or the hand pain diagram. Results Intrareader reliability was substantial to near perfect (kappa = 0.76 to 0.88). Interreader agreement was lower but still substantial (kappa = 0.60 to 0.67). Sensitivity of MRI was greatest for the overall impression of the images (96%) followed by increased median nerve signal (91%); however, specificities were low (33 to 38%). The length of abnormal signal on T2-weighted images was significantly correlated with nerve conduction latency, and median nerve area was larger at the distal radioulnar joint (15.8 vs 11.8 mm2) in patients with CTS. A logistic regression model combining these two MR variables had a receiver operating characteristic area under the curve of 0.85. Conclusions The reliability of MRI is high but the diagnostic accuracy is only moderate compared with a research-definition reference standard.

Self-administered Expanded Disability Status Scale with functional system scores correlates well with a physician-administered test.

Background: Patient-administered measures are needed to assess disability cost-effectively in large epidemiological studies. Setting: An outpatient clinic in a large multiple sclerosis center. Methods: A self-administered EDSS questionnaire was developed (EDSS-S). Consecutive patients with clinically definite multiple sclerosis completed the EDSS-S (n=95). During the same visit, a physician completed an EDSS (EDSS-P). Scores below 4.0 were determined using functional system (FS) scores. Scores above 4.0 were calculated by two methods, using gait alone and using gait and functional system scores combined. Results: EDSS-P scores ranged from 0-9.5 (mean 5.1, median 5.0, 78% female, age 17-78, mean age 45). Mean EDSS-P, EDSS-S and intraclass correlation coefficients of agreement were: EDSS using ambulation alone (4.6, 5.1, 0.89), EDSS using ambulation and FS scores (4.6, 5.3, 0.87), bowel/bladder FS scores (1.6, 1.7, 0.79), pyramidal FS scores (2.1, 2.4, 0.67), sensory FS scores (1.6, 2.1, 0.60), cerebellar FS scores (1.1, 1.6, 0.55), brainstem FS scores (0.5, 1.2, 0.45), vision FS scores (1.9, 1.3, 0.38), cerebral FS scores (0.6, 2.3, 0.27). Conclusions: Very good correlation was seen between patient and physician scores for EDSS and the bowel/bladder FS score. Four other FS scores correlated moderately. In general, patients scored themselves more disabled than physicians.

Prevalence of sleep problems in individuals with multiple sclerosis.

Background Sleep disturbance in multiple sclerosis has received little research attention despite the potential influence it may have on disease impact. Objective To estimate the prevalence of sleep disorders in a large community sample of individuals with multiple sclerosis. Methods A cross-sectional self-report survey of 1063 persons with multiple sclerosis. Sleep was assessed using the Womens Health Initiative Insomnia Rating Scale and Medical Outcomes Study Sleep measure. Results The prevalence of sleep problems in multiple sclerosis is significantly higher than in the general population or other chronic diseases and may affect women with multiple sclerosis more than men. Conclusion Sleep disturbance should routinely be evaluated in patients with multiple sclerosis and new interventions developed.

The scope and nature of pain in persons with multiple sclerosis

Much remains unknown about the scope, nature, and impact of pain on the lives of persons with multiple sclerosis (MS). In the present study, 180 community dwelling adults with MS completed a postal survey that included demographic measures, MS disease measures, and several standardized measures of pain, including pain intensity, variability, location, and pain-related interference. Some 66% of the sample reported pain, 25% of whom reported severe pain. Persons with pain reported an average of 6.6 distinct pain sites. Using the Brief Pain Inventory Interference Scale, the average level of overall pain interference was 3.33 (0- 10 scale) in the group reporting pain. The highest levels of pain interference were reported for sleep, recreational activities, and work in and outside the home. Persons with pain were more likely to report greater MS disease severity, poorer psychological functioning, and poorer health than persons with MS but not pain. Persons with pain were also less likely to be employed. These findings are consistent with previous research that shows that pain is common in MS, that it is severe in a substantial subset of these individuals and has the potential to negatively impact physical and psychosocial functioning over and above the effects of MS itself.

Psychosocial factors associated with pain intensity, pain-related interference, and psychological functioning in persons with multiple sclerosis and pain

Abstract Biopsychosocial models of chronic pain that recognize psychological and environmental factors as important aspects of adjustment to pain have been proposed for understanding chronic pain and related suffering in persons with multiple sclerosis (MS), but such models have not been empirically tested. The objective of this study was to test such a model by evaluating the associations of several psychosocial variables (i.e., pain‐related catastrophizing, perceived social support, pain beliefs, and pain coping) with pain intensity, pain interference with functioning, and psychological functioning in persons with chronic pain and MS, after controlling for demographic and disease‐related factors. Participants were 125 community‐dwelling persons with MS and pain who completed a mailed questionnaire that included measures of pain intensity and interference, psychological functioning, catastrophizing, social support, and pain beliefs and coping. The psychosocial variables accounted for an additional 25% of the variance in average pain intensity after controlling for demographic and disease‐related variables (p < .001). These variables explained an additional 22% of the variance in pain‐related interference (p < .001) and 43% of the variance in psychological functioning (p < .001), after adjusting for demographic and MS‐related variables and average pain intensity. Catastrophizing was consistently and independently associated with all criterion measures, whereas social support, pain beliefs, and pain coping were associated with some criterion measures but not others. The results provide empirical support for a biopsychosocial understanding of chronic pain in MS and suggest that specific psychosocial factors (e.g., catastrophizing) may be important regarding adjustment to pain in persons with MS.

Neuropathic Pain in Charcot-Marie-Tooth Disease

OBJECTIVES To determine the frequency and extent to which subjects with Charcot-Marie-Tooth (CMT) disease report pain and to compare qualities of pain in CMT to other painful neuropathic conditions. STUDY DESIGN Descriptive, nonexperimental survey, using a previously validated measurement tool, the Neuropathic Pain Scale (NPS). PARTICIPANTS Participants were recruited from the membership roster of a worldwide CMT support organization. MAIN OUTCOME MEASURES NPS pain descriptors reported in CMT were compared with those reported by subjects with postherpetic neuralgia (PHN), complex regional pain syndrome, type 1 (CRPS-1), also known as reflex sympathetic dystrophy, diabetic neuropathy (DN), and peripheral nerve injury (PNI). RESULTS Of 617 CMT subjects (40% response rate), 440 (71%) reported pain. with the most severe pain sites noted as low back (70%), knees (53%), ankles (50%), toes (46%), and feet (44%). Of this group, 171 (39%) reported interruption of activities of daily living by pain; 168 (38%) used non-narcotic pain medication and 113 (23%) used narcotics and/or benzodiazepines for pain. The use of pain description was similar for CMT, PHN, CRPS-1, DN, and PNI in terms of intensity and the descriptors hot, dull, and deep. CONCLUSIONS Neuropathic pain is a significant problem for many people with CMT. The frequency and intensity of pain reported in CMT is comparable in many ways to PHN, CRPS-1, DN. and PNI. Further studies are needed to examine possible pain generators and pharmacologic and rehabilitative modalities to treat pain in CMT.