Hand involvement in children with Charcot–Marie-Tooth disease type 1A

Quality of life and upper limb disability in Charcot-Marie-Tooth disease: A pilot study

Charcot-Marie-Tooth (CMT) patients present mainly lower limbs disability, with slowly progressive distal muscle weakness and atrophy, but hands impairment is a relevant problem affecting the quality of life (QoL). The evaluation of the upper limb is of primary importance. Often these patients present subclinical disorders or report difficulties in manipulating objects, with little evidence in the most used outcome measures. We aim to investigate the impact of hand impairment in the perceived QoL of CMT persons and secondly whether the Disability of Arm, Shoulder and Hand (DASH) scale can be useful in assessing upper limb abilities in CMT. We recruited 23 patients with confirmed genetic diagnosis of CMT. We performed a clinical evaluation with Sollerman Hand Function Test (SHFT), Thumb Opposition Test (TOT) and CMT examination score (CMTES). We completed the clinical assessment with DASH scale and the Short form 36 (SF36) questionnaire for a subjective evaluation of upper limb disability and quality of life. All patients also underwent an instrumental evaluation with a hand-held dynamometer measuring hand grip and tripod pinch and a sensor-engineered glove test (SEGT) to evaluate finger opposition movements in a quantitative spatial-temporal way. As expected, we found significant differences between CMT and control group performances in both clinical and instrumental assessment. Concerning QoL, we found that total score of SF36 and the SF36 Physical Composite Score (PCS) correlate with all clinical and instrumental Outcome Measures (OMs), particularly with Tripod pinch strength and TOT, which are considered major determinants of manual dexterity in CMT. DASH scale correlates with most clinical and instrumental OMs. Not surprisingly, we also found a correlation with DASH work, because CMT affects young patients engaged in work activities. However, we found a low correlation with the TOT and the dynamometer suggesting that DASH may not be the best scale for remote monitoring of upper limb disorders in CMT patients. Nevertheless, the results of our study confirm the usefulness of SF36 in recognizing the impact of upper limb disability in these subjects suggesting its use even in the remote monitoring of physical functioning.

Association Between Body Mass Index and Disability in Children With Charcot-Marie-Tooth Disease

BACKGROUND AND OBJECTIVES

This study examined the association between body mass index (BMI) and disability in children with Charcot-Marie-Tooth disease (CMT).

METHODS

We conducted a cross-sectional analysis of 477 patients with CMT who were 3 to 20 years of age from the Inherited Neuropathy Consortium and 316 age- and sex-matched healthy children from the 1,000 Norms Project. BMI was categorized according to the International Obesity Task Force (IOTF) criteria, and BMI categorization was compared with healthy children. IOTF categories (adult equivalent BMI cut points) were severely underweight (BMI <17 kg/m2), underweight (BMI ≥17-<18.5 kg/m2), healthy weight (BMI ≥18.5-<25 kg/m2), overweight (BMI ≥25-<30 kg/m2), and obese (BMI ≥30 kg/m2). Scores on the 0 to 44-point CMT Pediatric Scale (CMTPedS), a well-validated measure of disability, were examined in relation to BMI.

RESULTS

There was a higher proportion of children with CMT categorized as severely underweight (5.7% vs 0.3%), underweight (10.3% vs 5.1%), and obese (7.3% vs 3.8%) (p < 0.05). Fewer children with CMT were categorized as healthy weight (61.8% vs 74.4%) (p < 0.05), and the proportion of overweight (14.9% vs 16.5%) between groups was similar. CMTPedS scores (mean ± SD) for weight categories were as follows: severely underweight 27 ± 9, underweight 20 ± 8, healthy weight 17 ± 9, overweight 17 ± 9, and obese 22 ± 10. Compared to children with a healthy weight with CMT, being severely underweight was associated with being more disabled (p < 0.001), as was being obese (p = 0.015).

DISCUSSION

The proportion of children with CMT who are underweight or obese is higher compared to age- and sex-matched healthy children. In children with CMT, being underweight or obese is associated with greater disability, when compared to children with CMT of healthy weight.

Validation of a new hand function outcome measure in individuals with Charcot-Marie-Tooth disease

The symptomatology of Charcot-Marie-Tooth (CMT) disease mainly involves the feet and the hands. To date, there is no consensus on how to evaluate hand function in CMT. The aim of this study is to correlate the data of the engineered glove Hand Test System (HTS) with specific tests and the CMT examination score (CMTES). We analyzed 45 patients with the diagnosis of CMT using HTS, which measures the hand dexterity by specific sequences performed at maximum velocity. We completed the evaluation with the CMTES, tripod pinch and hand grip strength tested by a dynamometer, thumb opposition test (TOT), and Sollerman Hand function test (SHFT), and we conducted a test-retest with 20 normal subjects. Finger tapping (FT) and index-medium-ring-little (IMRL) sequence showed a significant correlation with CMTES (FT: dominant hand (DH): P = .036; non-dominant hand (NDH): P = .033; IMRL: DH: P = .009; NDH: P = .046). TOT correlated with CMTES significantly in both hands (P < .0001). tripod pinch showed a statistically significant correlation with CMTES (DH: P = .002; NDH: P = .005). Correlation between the hand grip and CMTES was significant only in DH (DH: P = .002). SHFT had a significant correlation with the CMTES (DH: P = .002). Test-retest showed a good reliability. HTS parameters correlate with CMTES confirming that this tool is sensitive to the hand deficits. In conclusion, we can state that HTS is a good, simple to use, and objective instrument to evaluate the hand function of CMT patients, but more studies on responsiveness and sensitivity are needed.

Multidimensional evaluation is necessary to assess hand function in patients with Charcot-Marie-Tooth disease type 1A

BACKGROUND

Charcot-Marie-Tooth (CMT) disease type 1A (CMT1A) is the most common hereditary neuropathy. Several studies have assessed the relation between axonal loss and grip strength; however, the functional impact on dexterity and health-related quality of life (HRQoL) is unknown. We hypothesized that the severity of axonal loss will be correlated with loss of function and HRQoL.

OBJECTIVE

The purpose of this study was to evaluate the relation between severity of electroneuromyography impairment and its impact on function and HRQoL in adults with CMT1A.

METHODS

Grip and lateral pinch strength were evaluated with specific dynamometers: the Jamar and the Pinch Gauge. Dexterity was explored with the Sollerman, Jebsen, and Nine-hole Peg tests. The CMT impact on well-being was assessed by the validated Medical Outcomes Study Short Form 36 (SF-36), Beck Depression Inventory, and Fatigue Severity Scale, and disease severity by the CMT neuropathy score and Inflammatory Neuropathy Cause and Treatment sensory sum score. Finally, axonal loss and demyelination process was assessed by electroneuromyography.

RESULTS

We included 33 participants with CMT1A (23 females, mean [SD] age 47.0 [4.7] years). We found lack of correlation between severe electroneuromyography impairment (frequency of abnormal results >80%), significant distal amyotrophy (70%) and quality of life (mean [SD] scores for physical and mental SF-36 36.4 [10.0] and 48.4 [11.5]), autonomy for activities of daily living, and hand function that remains relatively preserved. We found a correlation between lateral pinch and dexterity according to the Sollerman test (r=0.52, p<0.05) but a lack of correlation among the other parameters.

CONCLUSIONS

Electrophysiological follow-up seems to be of little relevance to follow HRQoL in individuals with CMT1A and manual function related to functional objectives for everyday physical medicine and rehabilitation practice. The manual function is complex and requires an overall, quantitative, qualitative and multidisciplinary assessment. Each tool (Pinch Gauge, Jamar, Sollerman, Jebsen, Nine-hole Peg) measures a specific element of manual function and is necessary when performing a grip function analysis.

Charcot-Marie-Tooth Disease and Other Genetic Polyneuropathies

PURPOSE OF REVIEW

Genetic polyneuropathies are rare and clinically heterogeneous. This article provides an overview of the clinical features, neurologic and electrodiagnostic findings, and management strategies for Charcot-Marie-Tooth disease and other genetic polyneuropathies as well as an algorithm for genetic testing.

RECENT FINDINGS

In the past 10 years, many of the mutations causing genetic polyneuropathies have been identified. International collaborations have led to the development of consortiums that are undertaking careful genotype-phenotype correlations to facilitate the development of targeted therapies and validation of outcome measures for future clinical trials. Clinical trials are currently under way for some genetic polyneuropathies.

SUMMARY

Readers are provided a framework to recognize common presentations of various genetic polyneuropathies and a rationale for current diagnostic testing and management strategies in genetic polyneuropathies.

Nine-hole Peg Test and Ten-meter Walk Test for Evaluating Functional Loss in Chinese Charcot-Marie-Tooth Disease

Background:

The 9-hole peg test (9-HPT) and 10-meter walk test (10-MWT) are commonly used to test finger motor function and walking ability. The aim of this present study was to investigate the efficacy of these tests for evaluating functional loss in Chinese Charcot-Marie-Tooth (CMT) disease.

Methods:

Thirty-four Chinese CMT patients (CMT group) from August 2015 to December 2016 were evaluated with 9-HPT, 10-MWT, CMT disease examination score, overall neuropathy limitation scale (ONLS), functional disability score, and Berg Balance Scale (BBS). Thirty-five age- and gender-matched healthy controls (control group) were also included in the study. Student's nonpaired or paired t-test were performed to compare data between two independent or related groups, respectively. The Pearson test was used to examine the correlations between recorded parameters.

Results:

The mean 9-HPT completion time in the dominant hand of CMT patients was significantly slower than that in the healthy controls (29.60 ± 11.89 s vs. 19.58 ± 3.45 s; t = −4.728, P < 0.001). Women with CMT completed the 9-HPT significantly faster than men with CMT (dominant hand: 24.74 ± 7.93 s vs. 33.01 ± 13.14 s, t = 2.097, P = 0.044). The gait speed of the average self-selected velocity and the average fast-velocity assessed using 10-MWT for CMT patients were significantly slower than those in the control group (1.03 ± 0.18 m/s vs. 1.44 ± 0.17 m/s, t = 9.333, P < 0.001; 1.31 ± 0.30 m/s vs. 1.91 ± 0.25 m/s, t = 8.853, P < 0.001, respectively). There was no difference in gait speed between men and women. Both 9-HPT and 10-MWT were significantly correlated with the ONLS, functional disability score, and BBS (P < 0.05 for all).

Conclusion:

The 9-HPT and 10-MWT might be useful for functional assessment in Chinese patients with CMT.

Reference values of intrinsic muscle strength of the hand of adolescents and young adults

STUDY DESIGN

A cross-sectional clinical measurement study.

INTRODUCTION

Measuring intrinsic hand muscle strength helps evaluate hand function or therapeutic outcomes. However, there are no established normative values in adolescents and young adults between 13 and 20 years of age.

PURPOSE OF THE STUDY

To measure hand intrinsic muscle strength and identify associated factors that may influence such in adolescents and young adults through use of the Rotterdam intrinsic hand myometer.

METHODS

A total of 131 participants (male: 63; female: 68) between 13 and 20 years of age completed the strength measurements of abductor pollicis brevis, first dorsal interosseus (FDI), deep head of FDI and lumbrical of second digit, flexor pollicis brevis (FPB), and abductor digiti minimi. Two trials of the measurements of each muscle were averaged for analyses. Self-reported demographic data were used to examine the influences of age, sex, and body mass index (BMI) on intrinsic hand muscle strength.

RESULTS

Normative values of intrinsic hand muscle strength were presented by age groups (13, 14, 15-16, 17-18, 19-20 year olds) for each sex category (male, female). A main effect of sex, but not age, on all the muscles on both the dominant (FPB: P = .02, others: P < .001) and non-dominant (FDI: P = .005, FPB: P = .01, others: P < .001) sides was found. A significant effect of BMI was found on dominant (P = .009) and non-dominant abductor pollicis brevis (P = .002). In addition, FDI (P = .005) and FPB (P = .002) were stronger on the dominant side than the non-dominant side.

DISCUSSION

Intrinsic hand muscle strength may be influenced by different factors including sex, BMI, and hand dominance. A larger sample is needed to rigorously investigate the influence of age on intrinsic strength in male and female adolescents and young adults.

CONCLUSION

The results provide reference values and suggest factors to be considered when evaluating hand function and therapeutic outcomes in both clinical and research settings. Further study is recommended.

LEVEL OF EVIDENCE

VI.

Established and novel measures of upper limb impairment in children with Charcot-Marie-tooth disease type 1A and riboflavin transporter deficiency type 2

Hand function is a problem in patients with Charcot-Marie-Tooth disease type 1A (CMT1A) and Riboflavin Transporter Deficiency type 2 (RTD2). However, a detailed understanding of upper limb involvement in these conditions is lacking. The aim of this pilot study was to compare hand and upper limb function between children with CMT1A, RTD2 and healthy controls using established and novel outcome measures. Three age-and sex-matched groups of four children (5-15 years, 1 male/group) with CMT1A, RTD2, and healthy controls were assessed for function, strength, and sensation. Fatigue and muscle activity of the FDI was also assessed using a submaximal contraction at 40% of the participants' maximal voluntary contraction. Functional measures were most affected in children with RTD2 followed by children with CMT1A, compared to healthy controls. Strength was similarly impaired in CMT1A and RTD2 compared to controls (p < 0.05). Sensation was significantly impaired in RTD2 compared to CMT1A and controls (p = 0.008). While time to fatigue did not differ between groups, a decline in muscle activity while force remained constant showed that controls compensated with other muscles during the fatigue task while children with CMT1A and RTD2 did not have this compensatory ability. Children with CMT1A and RTD2 exhibited marked hand/upper limb impairment. These results suggest the upper limb should be a focus of rehabilitative therapy in affected children using sensitive outcome measures of strength and sensation, as well as functional activities of daily living, which are most relevant to the patient.

Phenotypic Variability of Childhood Charcot-Marie-Tooth Disease

IMPORTANCE

Disease severity of childhood Charcot-Marie-Tooth disease (CMT) has not been extensively characterized, either within or between types of CMT to date.

OBJECTIVE

To assess the variability of disease severity in a large cohort of children and adolescents with CMT.

DESIGN, SETTING, AND PARTICIPANTS

A cross-sectional study was conducted among 520 children and adolescents aged 3 to 20 years at 8 universities and hospitals involved in the Inherited Neuropathies Consortium between August 6, 2009, and July 31, 2014, in Australia, Italy, the United Kingdom, and the United States. Data analysis was conducted from August 1, 2014, to December 1, 2015.

MAIN OUTCOMES AND MEASURES

Scores on the Charcot-Marie-Tooth Disease Pediatric Scale (CMTPedS), a well-validated unidimensional clinical outcome measure to assess disease severity. This instrument includes 11 items assessing fine and gross motor function, sensation, and balance to produce a total score ranging from 0 (unaffected) to 44 (severely affected).

RESULTS

Among the 520 participants (274 males) aged 3 to 20 years, CMT type 1A (CMT1A) was the most prevalent type (252 [48.5%]), followed by CMT2A (31 [6.0%]), CMT1B (15 [2.9%]), CMT4C (13 [2.5%]), and CMTX1 (10 [1.9%]). Disease severity ranged from 1 to 44 points on the CMTPedS (mean [SD], 21.5 [8.9]), with ankle dorsiflexion strength and functional hand dexterity test being most affected. Participants with CMT1B (mean [SD] CMTPedS score, 24.0 [7.4]), CMT2A (29.7 [7.1]), and CMT4C (29.8 [8.6]) were more severely affected than those with CMT1A (18.9 [7.7]) and CMTX1 (males: 15.3 [7.7]; females: 13.0 [3.6]) (P < .05). Scores on the CMTPedS tended to worsen principally during childhood (ages, 3-10 years) for participants with CMT4C and CMTX1 and predominantly during adolescence for those with CMT1B and CMT2A (ages, 11-20 years), while CMT1A worsened consistently throughout childhood and adolescence. For individual items, participants with CMT4C recorded more affected functional dexterity test scores than did those with all other types of CMT (P < .05). Participants with CMT1A and CMTX1 performed significantly better on the 9-hole peg test and balance test than did those with all other types of CMT (P < .05). Participants with CMT2A had the weakest grip strength (P < .05), while those with CMT2A and CMT4C exhibited the weakest ankle plantarflexion and dorsiflexion strength, as well as the lowest long jump and 6-minute walk test distances (P < .05). Multiple regression modeling identified increasing age (r = 0.356, β = 0.617, P < .001) height (r = 0.251, β = 0.309, P = .002), self-reported foot pain (r = 0.162, β = .114, P = .009), and self-reported hand weakness (r = 0.243, β = 0.203, P < .001) as independent predictors of disease severity.

CONCLUSIONS AND RELEVANCE

These results highlight the phenotypic variability within CMT genotypes and mutation-specific manifestations between types. This study has identified distinct functional limitations and self-reported impairments to target in future therapeutic trials.

Handwriting difficulties of children with Charcot-Marie-Tooth disease type 1A

Hand weakness and impaired manual dexterity have been reported in children with Charcot-Marie-Tooth disease type 1A (CMT1A). This early onset of upper limb involvement might explain frequent clinical referrals for assessment and treatment of impaired handwriting performance. The aim of this study was to examine the impact of CMT1A on handwriting speed and legibility, and identify demographic, anthropometric, and physical measures that might relate to handwriting performance. Handwriting speed (Handwriting Speed Test), handwriting legibility (Evaluation Tool of Children's Handwriting-Cursive), and hand strength (hand-held dynamometry of tip pinch, lateral pinch and grip) were assessed in 30 children with CMT1A (aged 8-17 years) and 30 age- and sex-matched controls. Children with CMT1A exhibited 34% slower handwriting speed (p < 0.0001) with 4% reduced legibility (p = 0.001) and 37-48% lower hand strength (p < 0.0001). All measures of strength, age, height, and weight were positively associated with handwriting speed (r = 0.39-0.79, p < 0.01). None of these factors related to handwriting legibility (p > 0.05). Regression modelling identified a diagnosis of CMT1A, lateral pinch weakness and younger age as significant independent predictors of slower handwriting speed, explaining 78% of the variance. Children with CMT1A have considerable handwriting difficulties, primarily with speed, and substantial associated hand and finger weakness. Understanding the cause-effect relationship between strength and function might provide modifiable targets for upper limb intervention.

Management of Charcot-Marie-Tooth disease: improving long-term care with a multidisciplinary approach

Charcot–Marie–Tooth (CMT) disease is the most common inherited neuropathy and one of the most common inherited diseases in humans. The diagnosis of CMT is traditionally made by the neurologic specialist, yet the optimal management of CMT patients includes genetic counselors, physical and occupational therapists, physiatrists, orthotists, mental health providers, and community resources. Rapidly developing genetic discoveries and novel gene discovery techniques continue to add a growing number of genetic subtypes of CMT. The first large clinical natural history and therapeutic trials have added to our knowledge of each CMT subtype and revealed how CMT impacts patient quality of life. In this review, we discuss several important trends in CMT research factors that will require a collaborative multidisciplinary approach. These include the development of large multicenter patient registries, standardized clinical instruments to assess disease progression and disability, and increasing recognition and use of patient-reported outcome measures. These developments will continue to guide strategies in long-term multidisciplinary efforts to maintain quality of life and preserve functionality in CMT patients.

Charcot-Marie-Tooth 1A: A narrative review with clinical and anatomical perspectives

Charcot-Marie-Tooth 1A (CMT1A) is regarded as the most common hereditary peripheral neurodegenerative disorder. This narrative review highlights perspectives around the historically well-established and characteristic anatomical manifestations of CMT1A seen in the feet, legs and hands, in addition to a clinical diagnosis that may be confirmed by electrophysiology, genetic or molecular markers together with the presence of a typical family history. A less well-known perspective is the potential for systemic manifestations and wider complication. The condition is characterised by a progressive clinical picture with unmistakable anatomical and neurological features that have been described since the late 19th century. There remains no cure although supportive, rehabilitative, and surgical regimes may provide helpful management or amelioration of symptoms. Most recently, the emergence of a pleotherapeutic approach suggests distinct promise. Future research focused on a detailed elucidation of the underlying molecular mechanisms underpinning myelin and axonal function may eventually hold the key to successful treatment of CMT1A. Genetic modification would potentially present a cure. Clin. Anat. 29:547-554, 2016. © 2015 Wiley Periodicals, Inc.

Pediatric Charcot-Marie-Tooth disease

Heritable diseases of the peripheral nerves (Charcot-Marie-Tooth disease [CMT]) affect the motor units and sensory nerves, and they are among the most prevalent genetic conditions in the pediatric patient population. The typical clinical presentation includes distal muscle weakness and atrophy, but the severity and progression are largely variable. Improvements in supportive treatment have led to better preservation of patients' motor functions. More than 80 genes have been associated with CMT. These genetic discoveries, along with the developments of cellular and transgenic disease models, have allowed clinicians to better understand the disease mechanisms, which should lead to more specific treatments.

Is overwork weakness relevant in Charcot-Marie-Tooth disease?

BACKGROUND

In overwork weakness (OW), muscles are increasingly weakened by exercise, work or daily activities. Although it is a well-established phenomenon in several neuromuscular disorders, it is debated whether it occurs in Charcot-Marie-Tooth disease (CMT). Dominant limb muscles undergo a heavier overload than non-dominant and therefore if OW occurs we would expect them to become weaker. Four previous studies, comparing dominant and non-dominant hand strength in CMT series employing manual testing or myometry, gave contradictory results. Moreover, none of them examined the behaviour of lower limb muscles.

METHODS

We tested the OW hypothesis in 271 CMT1A adult patients by comparing bilateral intrinsic hand and leg muscle strength with manual testing as well as manual dexterity.

RESULTS

We found no significant difference between sides for the strength of first dorsal interosseous, abductor pollicis brevis, anterior tibialis and triceps surae. Dominant side muscles did not become weaker than non-dominant with increasing age and disease severity (assessed with the CMT Neuropathy Score); in fact, the dominant triceps surae was slightly stronger than the non-dominant with increasing age and disease severity.

DISCUSSION

Our data does not support the OW hypothesis and the consequent harmful effect of exercise in patients with CMT1A. Physical activity should be encouraged, and rehabilitation remains the most effective treatment for CMT patients.

Longitudinal assessment of grip strength using bulb dynamometer in Duchenne Muscular Dystrophy

BACKGROUND

Grip strength is used to infer functional status in several pathological conditions, and the hand dynamometer has been used to estimate performance in other areas. However, this relationship is controversial in neuromuscular diseases and studies with the bulb dynamometer comparing healthy children and children with Duchenne Muscular Dystrophy (DMD) are limited.

OBJECTIVE

The evolution of grip strength and the magnitude of weakness were examined in boys with DMD compared to healthy boys. The functional data of the DMD boys were correlated with grip strength.

METHOD

Grip strength was recorded in 18 ambulant boys with DMD (Duchenne Group, DG) aged 4 to 13 years (mean 7.4 ± 2.1) and 150 healthy volunteers (Control Group, CG) age-matched using a bulb dynamometer (North Coast- NC70154). The follow-up of the DG was 6 to 33 months (3-12 sessions), and functional performance was verified using the Vignos scale.

RESULTS

There was no difference between grip strength obtained by the dominant and non-dominant side for both groups. Grip strength increased in the CG with chronological age while the DG remained stable or decreased. The comparison between groups showed significant difference in grip strength, with CG values higher than DG values (confidence interval of 95%). In summary, there was an increment in the differences between the groups with increasing age. Participants with 24 months or more of follow-up showed a progression of weakness as well as maintained Vignos scores.

CONCLUSIONS

The amplitude of weakness increased with age in the DG. The bulb dynamometer detected the progression of muscular weakness. Functional performance remained virtually unchanged in spite of the increase in weakness.

Flexor digitorum superficialis opposition tendon transfer improves hand function in children with Charcot-Marie-Tooth disease: case series

Charcot-Marie-Tooth disease limits hand function. Tendon transfer has not been reported in pediatric CMT. We report two severely affected children following long finger flexor digitorum superficialis opposition tendon transfer. Improvement was noted in palmar abduction, (30°/40°), opposition, (thumb to all digits), and acquisition of pincer, palmar, and lateral pinch with measureable force (1 lb). Dexterity testing improved on the 9 Hole Peg Test (1.03 s/77 s, 22 s) and Functional Dexterity Test (13 s/33 s, 88 s). Functional improvements were observed in self feeding, clothing management, and play. These cases support flexor digitorum superficialis opposition tendon transfer surgery to improve hand function in children with CMT.

Outcome measures for Charcot-Marie-Tooth disease: clinical and neurofunctional assessment in children

Charcot-Marie-Tooth (CMT) disease is the most common inherited neuromuscular disorder, presenting with symptoms often occurring since childhood, and showing a progressive course. At present, there are no valid and reliable measures for evaluation of impairment and disability in the pediatric population. The aim of this study was to determine the usefulness of outcome measures, commonly used in adult patients, in CMT children. We report the results of a comprehensive evaluation of 21 children affected with CMT type 1A, including clinical examinations, measure of hand and foot muscle strength with a hand-held dynamometer, and the following scales: CMT Neuropathy Score or its clinical component CMT Examination Score, Overall Neuropathy Limitations Scale (ONLS), Walk-12 questionnaire, and nine-hole peg test (9-HPT). Hand grip, three-point pinch, and foot dorsiflexion strength were significantly lower than age/sex equivalent in almost all cases. 9-HPT was significantly abnormal in 62% of patients and CMT Examination Score was <10 points in all cases. ONLS showed presence of minor disability in the upper limbs in 57% and mild abnormalities of gait in 71% of patients. Overall, these scales demonstrated limited potential to measure disability and severity of the disease confirming that it is necessary to identify specific scales for children with CMT.

A systematic review of dynamometry and its role in hand trauma assessment

The dynamometer was developed by American neurologists and came into general use in the late 19th century. It is still used in various ways as a diagnostic and prognostic tool in clinical settings. In this systematic review we assessed in detail the different uses of dynamometry, its reliability, different dynamometers used and the influence of rater experience by bringing together and evaluating all published literature in this field. It was found that dynamometry is applied in a wide range of medical conditions. Furthermore, the great majority of studies reported acceptable to high reliability of dynamometry. Jamar mechanical dynamometer was used most often in the studies reviewed. There were mixed results concerning the effect of rater experience. The factors influencing the results of dynamometry were identified as age, gender, body weight, grip strength, BMI, non/dominant hand, assessing upper/lower limbs, rater and patient’s strength and the distance from the joint where the dynamometer is placed. This review provides an understanding of the relevance and significance of dynamometry which should serve as a starting point to guide its use in hand trauma assessment. On the basis of our findings, we suggest that hand dynamometry has a great potential, and could be used more often in clinical practice.

Muscle cramp in pediatric Charcot-Marie-Tooth disease type 1A: prevalence and predictors

OBJECTIVES

To identify correlates of calf cramp in children with Charcot-Marie-Tooth disease type 1A (CMT1A).

METHODS

Throughout Australia, 81 children aged 2-16 years with CMT1A were recruited. Measures of strength, ankle range, foot posture, balance, agility, endurance, gait, and neurophysiology were collected. Post hoc logistic regression analyses were performed to identify independent predictors of calf cramp.

RESULTS

Of the 81 children, 26 (32%) reported calf cramp, and 1 child each reported toe, quadriceps, or arm cramp. Calf cramp was associated (p < 0.05) with older age; the presence of hand tremor; stronger foot inversion, eversion, dorsiflexion, and plantarflexion; and better performance in long-jump and 9-hole peg tests. Logistic regression analysis revealed only increasing age (odds ratio [OR] 1.32, 95% confidence interval [CI] 1.11-1.58; p = 0.002) and the presence of hand tremor (OR 3.81, 95% CI 1.18-12.56; p = 0.028) as independent predictors of calf cramp.

CONCLUSION

Calf cramps are common in children with CMT1A and worsen with age. This study revealed a previously unrecognized link between cramp and hand tremor in children with CMT1A. Further investigation of proposed mechanisms and risk factors common to both cramp and tremor will contribute to our understanding of these common complications of CMT1A.

Determinants of reduced health-related quality of life in pediatric inherited neuropathies

OBJECTIVE

We have shown that health-related quality of life (QOL) in children with inherited neuropathies (Charcot-Marie-Tooth disease [CMT]) is significantly reduced compared to population norms, thus establishing its utility as an outcome measure in therapeutic trials. However, the Australian ascorbic acid trial in children with CMT type 1A (CMT1A) identified no change in QOL scores despite a trend toward improvement in nerve conduction velocities in the treated group. The objective of this study was to identify clinical, electrophysiologic, and functional correlates of QOL in children with CMT1A, to guide future investigations of strategies to improve QOL and reduce disability in these patients.

METHODS

In this cross-sectional study, a series of multivariate regression models were developed to determine whether QOL scores could be explained by demographic and symptom data, standardized measures of gross motor function, foot/ankle and hand/finger involvement, electrophysiology, and gait characteristics in 70 children aged 5-16 years with CMT1A.

RESULTS

Independent determinants of reduced QOL in children with CMT1A, from strongest to weakest, were leg cramps, hand tremor, short step length, reduced long jump distance, ankle inflexibility, poor agility and endurance, advancing age, and foot drop. Many of the standardized clinical and electrophysiologic measures used as endpoints in clinical trials of CMT correlated poorly with QOL.

CONCLUSION

QOL is negatively affected by CMT1A in children. Multivariate modeling suggests that interventions designed to improve leg cramps, tremor, agility, endurance, and ankle flexibility might have a substantial effect on QOL in children with CMT1A.

Hereditary predominantly motor neuropathies

PURPOSE OF REVIEW

We review recent advances in Charcot-Marie-Tooth disease (CMT), the most frequent inherited neuromuscular disorder.

RECENT FINDINGS

During the last year further progresses have occurred in this field and concerned identification of novel mutations in recently identified genes, allowing better definition of associated phenotypes; increased knowledge on pathophysiologic mechanisms of the different CMT types, with the contribution of cellular and animal model studies; studies on the natural history of CMT and attempts at developing appropriate outcome measures to assess disease course and intervention efficacy; trials with ascorbic acid in CMT type 1A; and studies on new possible therapeutic strategies.

SUMMARY

Such advances have implications on clinical management of CMT and are modifying the clinical approach to CMT, by improving diagnostic tools, allowing better definition of prognosis, and increasing the hope for future effective treatments. Research on CMT is important as is shedding light on important pathways that regulates the normal function of axonal transport, vesicular trafficking, and also revealing new aspects of intracellular organelles' function and interactions.

Effect of oral curcumin on Déjérine-Sottas disease

Curcumin is the newest therapeutic agent for ameliorating the clinical and neuropathologic phenotype of a mouse model of Déjérine-Sottas disease. We undertook a 12-month dose-escalation safety trial of oral curcumin in a 15-year-old Caucasian girl with Déjérine-Sottas disease (point mutation, Ser72Leu) complicated by severe weakness, scoliosis, and respiratory impairment. The patient received 50 mg/kg/day oral curcumin for the first 4 months and 75 mg/kg/day thereafter, to complete a 12-month trial. Outcome measures included muscle strength, pulmonary function, upper/lower extremity disability, neurophysiologic studies, and health-related quality of life. After 12 months, the patient experienced no adverse events, and reported good compliance. There was little improvement in objective outcome measures. Knee flexion and foot strength increased slightly, but hand and elbow strength decreased. Pulmonary function, hand function, and measures of upper/lower extremity disability were stable or reduced. Her neurophysiologic findings were unchanged. Parent-reported quality of life improved for most domains, especially self-esteem, during the 12 months of treatment. Child-reported quality of life, assessed at the final visit, mirrored these results, with overall feelings of happiness and contentment. Further studies are required to explore the efficacy and safety of curcumin for severe demyelinating neuropathies of infancy and early childhood.