A Multidisciplinary Evaluation of Patients with DMD in An Italian Tertiary Care Center

With more widespread prolonged survival, Duchenne muscular dystrophy patients progressively experience multisystem complications. We retrospectively reviewed the charts of 132 Duchenne patients (112 alive/20 dead, age 3.5÷32.3 years) with the aims: 1) to provide a comprehensive description of the clinical status considering different aspects of the disease; 2) to propose a new scoring tool able to consider and pool together heterogeneous different functional. Five functions were analyzed: cardiac, respiratory, nutritional, ambulation and scoliosis. For each function, different items were considered and classified according to clinical severity (as indicated by international guidelines) and an incremental scoring was assigned. In addition, a global score incorporating all functions was defined. The scoring system confirmed that despite the significant protective role of steroids, all functions deteriorated with age. The severity of the global score became significantly higher since the age of 13 years. The severity of cardiac, respiratory and nutritional dysfunction was higher since 18 years. Deceased patients were characterized by significantly worse cardiac function, absence of steroid therapy and later use of respiratory assistive devices. The index proposed in this pilot study is a promising tool able to aggregate and correlate heterogeneous functions. It could become either an individual prognostic indicator of decline or a global score to evaluate changes in clinical trials therefore allowing multicenter studies, optimizing the management of both the primary and the secondary complications of the disease and understanding their relative impact.

Learning My Way: A Pilot Study of Navigation Skills in Cerebral Palsy in Immersive Virtual Reality

Purpose: Human navigation skills are essential for everyday life and rely on several cognitive abilities, among which visual-spatial competences that are impaired in subjects with cerebral palsy (CP). In this work, we proposed navigation tasks in immersive virtual reality (IVR) to 15 children with CP and 13 typically developing (TD) peers in order to assess the individual navigation strategies and their modifiability in a situation resembling real life. Methods: We developed and adapted to IVR an application based on a 5-way maze in a playground that was to be navigated to find a reward. The learning process, navigation strategies, and adaptation to changes were compared between participants with CP and their TD peers and correlated with visual-spatial abilities and cognitive competences. Results: Most participants with CP needed more attempts than TD participants to become proficient in navigation. Furthermore, the learning phase was correlated to visual-spatial memory but not with cognitive competences. Interestingly, navigation skills were comparable between groups after stabilization. While TD participants mainly relied on allocentric strategies based on environmental cues, egocentric (self-centered) strategies based on body motion prevailed in participants with CP. Furthermore, participants with CP had more difficulties in modifying their navigation strategies, caused by difficulties in executive processes beyond the visual-perceptual impairment, with an inefficient shift between implicit and explicit competences. Conclusions: The navigation abilities in participants with CP seem to be different from their TD peers in terms of learning and adaptation to new conditions; this could deeply affect their everyday life and ultimately participation and inclusion. A regular assessing and focused rehabilitative plans could help to better navigate the environment and affect self-perception.

Language Disturbances in a Group of Participants Suffering from Duchenne Muscular Dystrophy: A Pilot Study

Results from several studies suggest that the process of language acquisition may be altered in patients suffering from Duchenne Muscular Dystrophy. In this study, a group of 8 male participants with Duchenne Muscular Dystrophy ( M age = 16 yr., SD = 4.7) underwent an extensive neuropsychological and language assessment. They also performed a discourse production task. Results showed mild mental retardation associated with a specific deficit in Verbal rather than Performance IQ. At the linguistic assessment, 7 of 8 participants showed moderate to severe difficulties on oral language processing with particularly impaired morphosyntactic competence.

Whole-Brain DTI Assessment of White Matter Damage in Children with Bilateral Cerebral Palsy: Evidence of Involvement beyond the Primary Target of the Anoxic Insult

BACKGROUND AND PURPOSE

Cerebral palsy is frequently associated with both motor and nonmotor symptoms. DTI can characterize the damage at the level of motor tracts but provides less consistent results in nonmotor areas. We used a standardized pipeline of analysis to describe and quantify the pattern of DTI white matter abnormalities of the whole brain in a group of children with chronic bilateral cerebral palsy and periventricular leukomalacia. We also explored potential correlations between DTI and clinical scale metrics.

MATERIALS AND METHODS

Twenty-five patients (mean age, 11.8 years) and 25 healthy children (mean age, 11.8 years) were studied at 3T with a 2-mm isotropic DTI sequence. Differences between patients and controls were assessed both voxelwise and in ROIs obtained from an existing DTI atlas. Clinical metrics included the Gross Motor Function Classification System, the Manual Ability Classification System, and intelligence quotient.

RESULTS

The voxel-level and ROI-level analyses demonstrated highly significant (P < .001) modifications of DTI measurements in patients at several levels: cerebellar peduncles, corticospinal tracts and posterior thalamic radiations, posterior corpus callosum, external capsule, anterior thalamic radiation, superior longitudinal fasciculi and corona radiata, optic nerves, and chiasm. The reduction of fractional anisotropy values in significant tracts was between 8% and 30%. Statistically significant correlations were found between motor impairment and fractional anisotropy in corticospinal tracts and commissural and associative tracts of the supratentorial brain.

CONCLUSIONS

We demonstrated the involvement of several motor and nonmotor areas in the chronic damage associated with periventricular leukomalacia and showed new correlations between motor skills and DTI metrics.

Gait rehabilitation with a high tech platform based on virtual reality conveys improvements in walking ability of children suffering from acquired brain injury

The Gait Real-time Analysis Interactive Lab (GRAIL) is an instrumented multi-sensor platform based on immersive virtual reality for gait training and rehabilitation. Few studies have been included GRAIL to evaluate gait patterns in normal and disabled people and to improve gait in adults, while at our knowledge no evidence on its use for the rehabilitation of children is available. In this study, 4 children suffering from acquired brain injury (ABI) underwent a 5 session treatment with GRAIL, to improve walking and balance ability in engaging VR environments. The first and the last sessions were partially dedicated to gait evaluation. Results are promising: improvements were recorded at the ankle level, selectively at the affected side, and at the pelvic level, while small changes were measured at the hip and knee joints, which were already comparable to healthy subjects. All these changes also conveyed advances in the symmetry of the walking pattern. In the next future, a longer intervention will be proposed and more children will be enrolled to strongly prove the effectiveness of GRAIL in the rehabilitation of children with ABI.

Quantitative Evaluation of Performance during Robot-assisted Treatment

INTRODUCTION

This article is part of the Focus Theme of Methods of Information in Medicine on "Methodologies, Models and Algorithms for Patients Rehabilitation".

OBJECTIVES

The great potential of robots in extracting quantitative and meaningful data is not always exploited in clinical practice. The aim of the present work is to describe a simple parameter to assess the performance of subjects during upper limb robotic training exploiting data automatically recorded by the robot, with no additional effort for patients and clinicians.

METHODS

Fourteen children affected by cerebral palsy (CP) performed a training with Armeo®Spring. Each session was evaluated with P, a simple parameter that depends on the overall performance recorded, and median and interquartile values were computed to perform a group analysis.

RESULTS

Median (interquartile) values of P significantly increased from 0.27 (0.21) at T0 to 0.55 (0.27) at T1 . This improvement was functionally validated by a significant increase of the Melbourne Assessment of Unilateral Upper Limb Function.

CONCLUSIONS

The parameter described here was able to show variations in performance over time and enabled a quantitative evaluation of motion abilities in a way that is reliable with respect to a well-known clinical scale.

An ecological evaluation of the metabolic benefits due to robot-assisted gait training

Cerebral palsy (CP), one of the most common neurological disorders in childhood, features affected individual's motor skills and muscle actions. This results in elevated heart rate and rate of oxygen uptake during sub-maximal exercise, thus indicating a mean energy expenditure higher than healthy subjects. Rehabilitation, currently involving also robot-based devices, may have an impact also on these aspects. In this study, an ecological setting has been proposed to evaluate the energy expenditure of 4 children with CP before and after a robot-assisted gait training. Even if the small sample size makes it difficult to give general indications, results presented here are promising. Indeed, children showed an increasing trend of the energy expenditure per minute and a decreasing trend of the energy expenditure per step, in accordance to the control group. These data suggest a metabolic benefit of the treatment that may increase the locomotion efficiency of disabled children.

Kinematic analysis of upper limb during walking in diplegic children with Cerebral Palsy

Movements of the lower limbs during walking have been widely investigated in literature, while quantification of arm movement during gait is scanty. The aim of the present study was to assess quantitatively the upper limb motion during gait in children with Cerebral Palsy (CP). Sixteen children with diplegic CP were evaluated using a full-body marker set, which allows assessing both the lower and upper limb kinematics. Our results demonstrated that movement of the arms was characterized by an abducted shoulder and a more flexed elbow position at the initial contact of the gait cycle with a quite physiological range of motion if compared to controls. These data showed that gait of children with diplegic CP is generally characterized by abnormal upper limb position which could be considered a strategy to keep balance and posture control during walking.

Unimanual and bimanual intensive training in children with hemiplegic cerebral palsy and persistence in time of hand function improvement: 6-month follow-up results of a multisite clinical trial

This study aims to compare in hemiplegic children the effectiveness of intensive training (unimanual and bimanual) versus standard treatment in improving hand function, assessing the persistence after 6 months. A multicenter, prospective, cluster-randomized controlled clinical trial was designed comparing 2 groups of children with hemiplegic cerebral palsy, treated for 10 weeks (3 h/d 7 d/wk; first with unimanual constraint-induced movement therapy, second with intensive bimanual training) with a standard treatment group. Children were assessed before and after treatment and at 3 and 6 months postintervention using Quality of Upper Extremity Skills Test (QUEST) and Besta Scales. One hundred five children were recruited (39 constraint-induced movement therapy, 33 intensive bimanual training, 33 standard treatment). Constraint-induced movement therapy and intensive bimanual training groups had significantly improved hand function, showing constant increase in time. Grasp improved immediately and significantly with constraint-induced movement therapy, and with bimanual training grasp improved gradually, reaching the same result. In both, spontaneous hand use increased in long-term assessment.

Comparison of two pelvic positioning belt configurations in a pediatric wheelchair

Maintenance of stability for children in a wheelchair, particularly for those with spasticity, can be achieved through external stabilization components, such as pelvic positioning belts. Different kinds of pelvic belts exist on the market and one of the main characteristics is the different number of attachment points between the seat and the belt. As literature on this topic is limited to qualitative assessments, this study compared quantitatively 4-point versus 2-point pelvic positioning belts for the trunk fixation in 20 young patients with spasticity. Our data showed that 70% of the children required the use of pelvic belts on wheelchairs for stability and a better stability was observed with the 4-point belts than compared to the 2-point. Data generally showed in fact a higher percent of variation in terms of trunk flexion angleand knee joint angle with the 2-point belt than the 4-point belt, indicating increased submarining with the 2-point belt during sitting maintenance if compared to the 4-point belt (p < 0.05). According to our results, the 4-point belts seem to be the most effective configuration for patient stabilization, suggesting that its use prevents the thigh from submarining.

Rib cage deformities alter respiratory muscle action and chest wall function in patients with severe osteogenesis imperfecta

Background

Osteogenesis imperfecta (OI) is an inherited connective tissue disorder characterized by bone fragility, multiple fractures and significant chest wall deformities. Cardiopulmonary insufficiency is the leading cause of death in these patients.

Methods

Seven patients with severe OI type III, 15 with moderate OI type IV and 26 healthy subjects were studied. In addition to standard spirometry, rib cage geometry, breathing pattern and regional chest wall volume changes at rest in seated and supine position were assessed by opto-electronic plethysmography to investigate if structural modifications of the rib cage in OI have consequences on ventilatory pattern. One-way or two-way analysis of variance was performed to compare the results between the three groups and the two postures.

Results

Both OI type III and IV patients showed reduced FVC and FEV₁ compared to predicted values, on condition that updated reference equations are considered. In both positions, ventilation was lower in OI patients than control because of lower tidal volume (p<0.01). In contrast to OI type IV patients, whose chest wall geometry and function was normal, OI type III patients were characterized by reduced (p<0.01) angle at the sternum (pectus carinatum), paradoxical inspiratory inward motion of the pulmonary rib cage, significant thoraco-abdominal asynchronies and rib cage distortions in supine position (p<0.001).

Conclusions

In conclusion, the restrictive respiratory pattern of Osteogenesis Imperfecta is closely related to the severity of the disease and to the sternal deformities. Pectus carinatum characterizes OI type III patients and alters respiratory muscles coordination, leading to chest wall and rib cage distortions and an inefficient ventilator pattern. OI type IV is characterized by lower alterations in the respiratory function. These findings suggest that functional assessment and treatment of OI should be differentiated in these two forms of the disease.

Specific profiles of neurocognitive and reading functions in a sample of 42 Italian boys with Duchenne Muscular Dystrophy

A group of 42 Italian boys with Duchenne Muscular Dystrophy was compared with a control group of 10 boys with Spinal Muscular Atrophy and Osteogenesis Imperfecta on tests assessing general intellectual ability, language, neuropsychological functions, and reading skills with the aim of describing a comprehensive profile of the various functions and investigating their interrelationships. The influence of general intellectual level on performance was analyzed. Further, correlations between various neuropsychological measures and language performances were computed for the group with Duchenne Muscular Dystrophy, as well as the correlations between reading scores and other cognitive and linguistic measures. A general lowering in VIQ, PIQ, and FSIQ scores was found to characterize the group with Duchenne Muscular Dystrophy. Expressive language skills were within the normal range, while syntactic and grammatical comprehension were significantly impaired. The presence of below-average reading performances was further confirmed. However, unlike previous studies on irregular orthographies, the present results show that (a) the mild reading difficulties found in the sample essentially concern speed rather than accuracy; (b) they concern word rather than nonword reading; (c) lower reading performances are related to lower scores in general IQ; (d) no correlations emerge with phonological abilities, verbal short-term memory, or working memory, but rather with long-term memory and lexical skills. This may suggest that language-specific effects modulate the cognitive expressions of Duchenne Muscular Dystrophy and raises the possibility that the dysfunctions underlying the reading difficulties observed in affected readers of regular orthographies involve different neurocognitive systems than the cortico-cerebellar circuits usually invoked.

Nitric oxide donor and non steroidal anti inflammatory drugs as a therapy for muscular dystrophies: evidence from a safety study with pilot efficacy measures in adult dystrophic patients

This open-label, single centre pilot study was designed to evaluate safety and tolerability of the combination of the drugs isosorbide dinitrate, a nitric oxide donor, and ibuprofen, a non steroid anti-inflammatory drug, in a cohort of adult dystrophic patients (Duchenne, Becker and Limb-Girdle Muscular Dystrophy). Seventy-one patients were recruited: 35, treated with the drug combination for 12 months, and 36 untreated. Safety and adverse events were assessed by reported signs and symptoms, physical examinations, blood tests, cardiac and respiratory function tests. Exploratory outcomes measure, such as the motor function measure scale, were also applied. Good safety and tolerability profiles of the long-term co-administration of the drugs were demonstrated. Few and transient side effects (i.e. headache and low blood pressure) were reported. Additionally, exploratory outcomes measures were feasible in all the disease population studied and evidenced a trend towards amelioration that reached statistical significance in one dimension of the MFM scale. Systemic administration of ibuprofen and isosorbide dinitrate provides an adequate safety margin for clinical studies aimed at assessing efficacy.

Low abdominal contribution to breathing as daytime predictor of nocturnal desaturation in adolescents and young adults with Duchenne Muscular Dystrophy

In the respiratory management of DMD patients it is still under debate what parameter should indicate the correct timing for institution of nocturnal non-invasive ventilation (NIV), in addition to forced vital capacity, which is generally considered as a prognostic marker of disease progression. The aim of this study was to determine if volume variations of rib cage and abdominal compartments measured by Opto-Electronic Plethysmography can be helpful to distinguish between those patients who are in the early stages of nocturnal oxygen desaturation development and those who do not yet. Pulmonary function, abdominal contribution to tidal volume and to inspiratory capacity (%Abd IC) and a set of breathing pattern indexes were assessed in 40 DMD patients older than 14 years and not yet under nocturnal NIV. ROC analysis revealed that among all the considered parameters, %Abd IC in supine position was the best discriminator between DeSat (at least 10% of the night time with SpO(2) < 95%) and NonDeSat patients, providing an area under the curve with 95%CI equal to 0.752. In conclusion, in adolescents and adults DMD patients who present either no sign or only mild nocturnal oxygen desaturation, a reduced abdominal contribution to inspiratory capacity is a marker of the onset of diaphragm weakness and should be considered to identify the correct timing for the institution of nocturnal NIV.

3D gait analysis in patients with hereditary spastic paraparesis and spastic diplegia: a kinematic, kinetic and EMG comparison

The predominant clinical feature of patients with Hereditary Spastic Paraparesis (HSP) is gait disturbance owing to spasticity and weakness of the lower limbs; the spasticity in early-onset disease (infancy or childhood) often cannot be distinguished from mild form of spastic diplegia (SD). The aim of this study was to quantify the gait strategy in HSP and SD children, focusing on the differences between groups as concerns functional limitation during gait. 9 HSP and 16 SD children were evaluated using Gait Analysis; kinematic and kinetic parameters and EMG pattern during walking were identified and calculated to compare the two gait strategies. The results revealed that these two pathologies are characterised by different gait strategies. In particular we found that knee joint, in terms of kinematics and kinetics, and rectus femoris pattern represent discriminatory aspects in order to compare and differentiate gait patterns of HSP and SD children. The findings strongly support the issue that HSP and SD patients need individualised therapeutical program, either neurosurgical or pharmacological treatment, based on the quantification of gait deficiencies and in order to address the peculiarity of their motor limitations and to prevent the onset of compensatory strategies.

The perception of involved professionals towards research feasibility and usefulness: lessons from the Multi-Site Trial on Efficacy of Constraint Induced Movement Therapy in Children with Hemiplegia

BACKGROUND

In the last decades, the world of rehabilitation has been more and more calling for clear evidence to support intervention and numerous research programs have been developed. At stake, relatively little research on opinions and attitude of rehabilitation personnel involved in research conducted in real clinical settings has been carried out.

AIM

To explore the opinion of professionals involved in a national clinical trial on research.

DESIGN

Multicentre cross-sectional study.

SETTING

19 rehabilitation centres/services (4 research institutes, 15 local rehabilitation services).

POPULATION

All professional participating to a multi-centre clinical trial on the effects of Constraint Induced Movement Therapy on children with hemiplegic cerebral palsy.

METHODS

A 15-questions questionnaire inquiring feasibility, usefulness, products, costs, judgement and perceptions about clinical research in rehabilitation was administered.

RESULTS

Among those working in one of the 19 rehabilitation centres part of the multicentric study, 76 professionals were asked to fill in the questionnaire. 68 professionals answered (89.4% of response rate). More than 75% of the sample thinks that its rehabilitation centre is suited to develop clinical research. Research results useful for the development of their daily activities (new tools for the assessment of children, to demonstrate the efficacy of a new treatment option and to learn a new way of working, and to strengthen the ties within the working team). Research is costly in terms of personal time and effort, but it can modify the rehabilitation praxis (assessment tools, the relationship with colleagues/patients). 98% of the interviewees declared the willingness to participate to other research projects.

CONCLUSION AND CLINICAL REHABILITATION IMPACT

This survey highlights the importance of conducting research in local rehabilitation services, not only in terms of generation of new evidences, but also in terms of building networks, sharing experiences and knowledge, connecting with centers of excellence and providing a specific training for research conduction.

Pilot studies suggesting new applications of NiTi in dynamic orthoses for the ankle joint

NiTi is a metal alloy with unconventional functional characteristics: Shape memory and pseudoelasticity. Its use in the field of rehabilitation is very innovative. This work presents applications in lower limb orthotics. Three different devices were assembled and tested: An equinus gait dynamic splint, a compliant ankle positioning brace, and a dual-mode haptic/active exerciser for the dorsiflexors. Results are derived from technical and preclinical trials. The gait splint improves several walking parameters even better than a traditional flexible ankle-foot orthoses (AFO). In particular, it supports mid-stance and propulsion biomechanics and affects physiological activation of tibialis anterior during swing much less than posterior leaf AFO. The haptic/active exerciser, able to provide dorsiflexion through a suitable articular range, could be controlled on the basis of minimal surface electromyographic (sEMG) signals, suggesting its use as an aid for early active workouts as soon as patients start to recover voluntary control of tibialis anterior. Further evidence must be sought in future to confirm for the ankle joint the promising results obtained in repositioning applications in prior upper limb studies. The work done so far on the tested prototypes is encouraging: Material characteristics and dimensioning will be optimized so that customized NiTi devices can be prescribed to best meet individual patients' requirements.

Assessment of gait recovery in children after Traumatic Brain Injury

OBJECTIVE

The aims were: (1) to quantify the functional limitation of children at the beginning of recovery of independent ambulation after Traumatic Brain Injury (TBI), using clinical-functional scales; (2) to evaluate the changes in gait pattern during rehabilitation (about 5 months later), using 3D Gait Analysis (GA) in post-acute phase; (3) to investigate the presence of correlation among parameters obtained by 3DGA, clinical assessment and measures connected with the trauma.

METHODS

Fourteen children with hemiplegia after severe TBI were evaluated at independent gait recovery (S0) and 5.5 months later (S1) by clinical assessment (GOS, DRS, WeeFIM and GMFM) and 3D GA (spatio-temporal parameters, kinematics and kinetics).

RESULTS

At S1 all clinical measures had improved. Regarding spatio-temporal parameters, velocity and step length improved. Significant progress was evident at the ankle joint, while an unchanged condition appeared at pelvis and hip in sagittal plane with a worsening of hip rotation which increased its internal rotation. Significant correlations were found between motor performance, clinical assessment and trauma-related measures.

CONCLUSIONS

Repeated GA and clinical evaluations were useful in quantifying the motor recovery of children with TBI during rehabilitation underpinning the role of GA in quantifying these modifications in an objective and non-invasive way.

Abdominal volume contribution to tidal volume as an early indicator of respiratory impairment in Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is characterised by progressive loss of muscular strength that leads to an increasingly restrictive pulmonary syndrome. However, it is still not clear whether this determines alterations in the breathing pattern. We studied: 66 DMD patients at different stages of the disease (mean+/- sem age 12.6+/-0.6 yrs, range 5-22 yrs of age), subdivided into four groups according to age; and 21 age-matched healthy male controls. Spirometry, lung volumes and nocturnal oxygen saturation were measured in all DMD patients. Ventilatory pattern and chest wall volume variations were assessed by optoelectronic plethysmography during spontaneous breathing both in seated and supine positions. Whilst in a seated position, no significant differences were found between patients and controls or between different age groups. In the supine position, the average contribution of abdominal volume change (DeltaV(AB)) to tidal volume progressively decreased with age (p<0.001). The patients who showed nocturnal hypoxaemia showed significantly lower Delta V(AB). In conclusion, chest wall motion during spontaneous breathing in awake conditions and in supine position is an important indicator of the degree of respiratory muscle impairment in DMD. DeltaV(AB) is not only an important marker of the progression of the disease but is also an early indicator of nocturnal hypoxaemia.

Relationship between kinematic knee deviations and femoral anteversion in children with cerebral palsy

The aim of the study was to determine the possible correlation between the degree of femoral anteversion and the quantitative data obtained by 3D Gait Analysis (GA) and then to investigate the relationship between femoral anteversion and the reduced knee flexion during swing phase in children with Cerebral Palsy. Twenty-seven diplegic children with severe rectus femoris spasticity and 20 healthy children (CG) were considered. Clinical evaluation of femoral anteversion, Duncan Ely test and Gait Analysis were performed in all patients. From Gait Analysis data some indices were identified and calculated and statistical analysis performed. Clinical evaluations made the distinction between patients with excessive femoral anteversion (Group 1) and those with normal value (Group 2). Both groups showed a blunt maximum of knee flexion in swing (KMSw), representative of rectus femoris spasticity, but two different gait strategies were found for the timing of KMSw. Group 1 exhibited a reduced KMSw value with its timing close to normal value and an excessive hip internal rotation (Mean Hip Rotation index), correlated to high femoral anteversion; Group 2 presented a limited KMSw and a significant delay of its timing, with Mean Hip Rotation index close to Control Group. No differences were found for other indices. The results demonstrated that the presence of reduced KMSw only can be directly connected to excessive femoral anteversion; the coexistence of reduced KMSw and its delayed timing reveals that the rectus femoris spasticity may be due to rectus spasticity added to an incorrect motor selective control. The results are clinically crucial for treatment strategies (derotative femoral osteotomy vs rectus transfer).

Point mutations and a large intragenic deletion in SPG11 in complicated spastic paraplegia without thin corpus callosum

BACKGROUND

Hereditary spastic paraplegia (HSP) with thin corpus callosum (HSP-TCC) is a frequent subtype of complicated HSP clinically characterised by slowly progressive spastic paraparesis with cognitive impairment and thin corpus callosum (TCC). SPG11, the gene associated with the major locus involved, encodes spatacsin, a protein of unknown function.

METHODS

Different types of mutations were identified in patients with the complex form of HSP (cHSP) including TCC. We screened a series of 45 index patients with different types of cHSP with (n = 10) and without (n = 35) TCC.

RESULTS

Ten mutations, of which five are novel, were detected in seven patients. Of importance, three out of seven mutated patients present with cHSP without TCC. Among the novel mutations identified, we characterised a large intragenic rearrangement deleting 2.6 kb of the SPG11 gene. The rearrangement is due to non-allelic homologous recombination between Alu sequences flanking the breakpoints.

CONCLUSIONS

These findings expand the mutation spectrum of SPG11 and suggest that SPG11 mutations may occur more frequently in familial than sporadic forms of cHSP without TCC. This helps to define further clinical and molecular criteria for a correct diagnosis of the SPG11 related form of cHSP. In addition, the intragenic deletion detected here, and the mechanism involved, both provide clues to address the issue of SPG11 missing mutant alleles previously reported.

Gait pattern in Duchenne muscular dystrophy

We investigated the gait pattern of 21 patients with Duchenne muscular dystrophy (DMD), compared to 10 healthy controls through 3D Gait Analysis. An overall observation of gait pattern in our DMD patients when compared to controls confirmed the data previously reported for small dystrophic groups. An excessive anterior tilt of pelvis and abnormal knee pattern in loading response phase were found. Since during the swing phase the DMD foot is too plantarflexed, patients adopt a higher flexion and abduction of the hip in order to advance the swinging limb. Velocity and cadence of DMD patients resulted similar to those calculated for healthy subjects, whereas stride length was reduced and step width was increased. We then divided the DMD patients in to two subgroups (treated with steroids and untreated), and we observed that the only statistically significant differences between the two groups in Gait Analysis parameters were found for the maximum of ankle power. 3D Gait Analysis gives objective and quantitative information about the gait pattern and the deviations due to muscular situation of DMD subjects; being our study a single moment evaluation, it is otherwise unable to unravel changes only detectable through serial analysis during the time course of the disease and, if any, due to the treatment.

A clinical, genetic, and biochemical characterization of SPG7 mutations in a large cohort of patients with hereditary spastic paraplegia

Mutations in the SPG7 gene encoding a mitochondrial protein termed paraplegin, are responsible for a recessive form of hereditary spastic paraparesis. Only few studies have so far been performed in large groups of hereditary spastic paraplegia (HSP) patients to determine the frequency of SPG7 mutations. Here, we report the result of a mutation screening conducted in a large cohort of 135 Italian HSP patients with the identification of six novel point mutations and one large intragenic deletion. Sequence analysis of the deletion breakpoint, together with secondary structure predictions of the deleted region, indicate that a complex rearrangement, likely caused by extensive secondary structure formation mediated by the short interspersed nuclear element (SINE) retrotransposons, is responsible for the deletion event. Biochemical studies performed on fibroblasts from three mutant patients revealed mild and heterogeneous mitochondrial dysfunctions that would exclude a specific association of a complex I defect with the pathology at the fibroblast level. Overall, our data confirm that SPG7 point mutations are rare causes of HSP, in both sporadic and familial forms, while underlying the puzzling and intriguing aspects of histological and biochemical consequences of paraplegin loss.

Evaluation of narrative abilities in patients suffering from Duchenne Muscular Dystrophy

The present work investigated cognitive, linguistic and narrative abilities in a group of children suffering from Duchenne Muscular Dystrophy, an allelic X-linked recessive disorder caused by mutations in the gene encoding dystrophin. The patients showed mildly reduced IQ with lower Verbal than Performance Intelligence Quotient and were mildly affected in visual attention and short-term memory processing. At the linguistic assessment, neither receptive (word comprehension) nor expressive (naming tasks and fluency) lexical abilities were impaired. However, their narratives were qualitatively inferior with respect to those produced by a group of typically developing children. Their speech samples were characterized by the presence of fewer verbs and complete sentences. It is suggested that the reduced production of complete sentences is due to a selective problem in verb argument structure generation. Since the lack of dystrophin is assumed to produce effects on the maturation of the cerebellum, whose involvement has been recently suggested in verb and syntactic processing, these findings may lend indirect support to the hypothesis of a cerebellar-cortical circuit specialized in verb and sentence production.

Quantification of energy expenditure during gait in children affected by cerebral palsy

AIM

Children affected by cerebral palsy (CP) are generally characterised by some movement limitations and abnormalities that compromised gait pattern. These disabilities during deambulation may lead to excessive energy cost and so to a compromised energy efficiency.

METHODS

In this study oxygen expenditure was evaluated during walking in 20 children affected by CP and in 20 healthy children, using Cosmed K4b2 (Cosmed, Italy). From obtained data about energy consumption, some parameters (heart rate, energy expenditure index, oxygen consumption, oxygen cost) were extracted, first in order to quantify energy cost during gait in pathological and healthy subjects and then to underline differences between the 2 groups of children.

RESULTS

In particular, the results obtained revealed that heart rate (bpm) and oxygen consumption (mL/kg/min) mean values didn't differ significantly between normal subjects and those with CP; instead, energy expenditure index (b/m) and oxygen cost (mL/kg/m) presented higher mean values rather than control group at a statistically level and so they revealed to be significant parameters, in order characterized energy expenditure in children affected by CP.

CONCLUSIONS

This inefficiency characteristic of CP deambulation is probably directly connected to the presence of simultaneous contraction of agonist and antagonist muscle in these patients.

Are patients with hereditary spastic paraplegia different from patients with spastic diplegia during walking? Gait evaluation using 3D gait analysis

Patients with hereditary spastic paraplegia (HSP) often resemble patients with mild spastic diplegia (SD), although their motor limitations differ. The aim of this study was to analyse quantitatively the gait of HSP and SD subjects in order to define the gait pattern in HSP and the differences between the two conditions. Fifteen subjects with HSP, 40 patients with SD and 20 healthy subjects underwent gait analysis (GA). The spatio-temporal and kinematic parameters at the proximal joints were found to be similar in HSP and SD, whereas the most significant differences were found at the knee and ankle joints. Both groups displayed a tendency for knee hyperextension in the midstance phase, but the duration of this hyperextension was longer in the HSP patients. This study shows that GA complements traditional clinical evaluations, making it possible to distinguish, clearly, between motor ability in HSP and in SD patients; the duration of the knee hyperextension during midstance was found to discriminate between the two gait patterns.

Quantitative analysis of gait pattern and energy consumption in children with cerebral palsy

The measurement of oxygen consumption during walking allows the quantification of gait expenditure, mainly in patients with musculoskeletal disabilities, as in cerebral palsy (CP). In this study, first, an experimental set up for the acquisition of energy consumption during gait analysis (GA) was proposed; secondly, some parameters of energy expenditure were analyzed to characterize pathological gait from an energetic point of view. Twenty CP children and 20 healthy children were evaluated during two consecutive sessions (session 1: only GA was performed; session 2: K4b2 was used during GA acquisition). The results revealed that the experimental set up was comfortable for all subjects. The absence of any differences in GA values between the two sessions showed that the use of a device for energy acquisition does not modify gait pattern. Energy expenditure index and oxygen cost presented abnormal values in comparison with normality and they were significant to quantify energy expenditure in CP children.

Early onset, non fluctuating spinocerebellar ataxia and a novel missense mutation in CACNA1A gene

Mutations in the brain-specific P/Q type Ca2+ channel alpha1 subunit gene, CACNA1A, have been identified in three clinically distinct disorders, spinocerebellar ataxia type 6 (SCA6), episodic ataxia type 2 (EA2), and familial hemiplegic migraine type 1 (FHM1). SCA6 is associated with small expansions of a CAG repeat at the 3' end of the gene, while point mutations are mostly responsible for its two allelic disorders, FHMI and EA2. From the electrophysiological point of view, while FHMI mutations lead to a gain of function [Tottene A, Fellin T, Pagnutti S, Luvisetto S, Striessnig J, Fletcher C, et al. Familial hemiplegic migraine mutations increase Ca2+ influx through single human CaV2.1 channels and decrease maximal CaV2.1 current density in neurons. Proc Natl Acad Sci 99 (20) (2002) 13284-13289.], EA2 mutations usually generate a loss of channel function [Guida S, Trettel F, Pagnutti S, Mantuano E, Tottene A, Veneziano L, et al. Complete loss of P/Q calcium channel activity caused by a CACNA1A missense mutation carried by patients with episodic ataxia type 2. Am J Hum Genet 68 (3) (2001) 759-764, Wappl E, Koschak A, Poteser M, Sinnegger MJ, Walter D, Eberhart A, et al. Functional consequences of P/Q-type Ca2+ channel Cav2.1 missense mutations associated with episodic ataxia type 2 and progressive ataxia. J Biol Chem 277 (9) (2002) 6960-6966.]. In the present study, we describe a child affected by permanent non-fluctuating limb and trunk ataxia with a quite early age of onset. Interestingly, the size of the CACNA1A triplet repeat region in the patient is within the normal range while he carries a novel de novo missense mutation in this gene, p.R1664Q. Although functional data are not available, based on the literature data indicating that severe reductions in P/Q-type channel activity favour episodic and/or progressive ataxic symptoms [Wappl E, Koschak A, Poteser M, Sinnegger MJ, Walter D, Eberhart A, et al. Functional consequences of P/Q-type Ca2+ channel Cav2.1 missense mutations associated with episodic ataxia type 2 and progressive ataxia. J Biol Chem 2002;277(9):6960-6966.], we hypothesize that the functional consequence of the mutation here identified is a partial loss of the Ca channel function. In conclusion, the clinical and molecular findings reported here suggest the opportunity to screen for point mutation in this gene, even patients with a clinical phenotype for some aspects slightly different from the typical picture more commonly associated to SCA6, EA2 or FHM1 diseases.

Loss of Dp140 dystrophin isoform and intellectual impairment in Duchenne dystrophy

BACKGROUND

Mental retardation is a clinical feature of Duchenne dystrophy (DD) and affects about one-third of patients. No clear association has been found between DNA mutations, protein expression, and IQ scores, although distal deletions in the dystrophin gene have been reported in association with intellectual impairment. A role for the brain distal dystrophin isoform Dp140 was suggested.

OBJECTIVE

To explore the possible association between cognitive impairment and DNA macrodeletions in the distal part of the gene, including Dp140 gene region.

METHODS

Sixty-six patients with DD received general intelligence assessment by Wechsler Intelligence Scales measuring full, verbal, and performance IQ. PCR analysis was performed to detect deletions in the dystrophin gene, and the Dp140 regulatory region was analyzed in a subgroup of 12 patients. Statistical analysis was performed by nonparametric Wilcoxon rank signed and rank sum tests.

RESULTS

Comparison of neuropsychological and genetic data revealed an association between distal macrodeletions and cognitive impairment (p < 0.001). Comparing deletions involving the Dp140 gene region with deletions presumably not altering Dp140 expression resulted in even greater significance.

CONCLUSIONS

These data suggest that in DD, distal dystrophin deletions are associated with intellectual impairment. This study highlights a possible role for the brain distal isoform Dp140 in normal cognitive development.

Focal cognitive impairment in mitochondrial encephalomyopathies: a neuropsychological and neuroimaging study

Mitochondrial encephalomyopathies (ME) are a multisystemic group of diseases characterized by a wide range of biochemical and genetic mitochondrial defects with a variable mode of inheritance. We studied the neuropsychological profile, magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT) data in a group of ME patients in order to look for common or specific cognitive defects and a possible correlation with related brain areas. Three main cognitive areas were assessed: general intelligence, memory functions and visuo-perceptual skills. Our sample included 16 ME patients (nine males, seven females) aged 25-68 years (mean age 45.2, SD 13.0). No sign of mental deterioration was found in the group of elderly subjects. Despite subjects showing no global cognitive impairment they scored lower in nonverbal versus verbal tasks. Visuo-spatial skills and short-term memory were selectively impaired. There was no correlation between neuropsychological results and age, illness duration, age of onset, clinical phenotypes, genetic mitochondrial alterations and pharmacological therapy. The most frequent SPECT pattern observed was the hypoperfusion of temporal lobes, with a direct localization in the temporal cortex and with prevalent mesial involvement. The neuropsychological profile and SPECT imaging revealed similarities with focal defects.