Six-minute walk test is reliable and sensitive in detecting response to therapy in CIDP

OBJECTIVE

The current clinical measures (ONLS, R-ODS, mRS, and MRC) may not be so sensitive in capturing minimal variations or measuring fatigue in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Our aim was to assess if 6-min walk test (6MWT) is able to increase the sensitivity in detecting response to therapy and to capture fatigue in CIDP patients.

METHODS

We tested 6MWT in 42 CIDP patients. Using both anchor-based and distribution-based approaches, we estimated the meaningful clinical change after therapy by calculating the minimum improvement cutoff (Minimal Clinically Important Difference Score-MCID) required for considering a patient as responder. We calculated the sensitivity of the 6MWT versus the other clinical outcomes. We analysed fatigue by comparing the velocities between first and sixth minutes of the 6MWT and the effect of treatment on fatigue using an ANOVA model for repeated measures.

RESULTS

MCID resulted equal to 20 m. The combination of 6MWT-MCID cutoff with the other clinical measures led to identify 74% of responders. The sensitivity of the 6MWT was 90% versus 77% of the other clinical measures. The 6MWT was also sensitive in capturing fatigue-related changes, even though fatigue was not influenced by treatment.

CONCLUSIONS

The combination of the 6MWT with the other clinical measures increased the chance to detect the quote of responders. We propose to include the 6MWT in the routine assessment of CIDP patients and the MCID cutoff at 20 m could be set for identifying the responders and properly guiding the therapy management.

One-year follow up of three Italian patients with Duchenne muscular dystrophy treated with ataluren: is earlier better?

Background

Ataluren was approved for the treatment of nmDMD, both the efficacy and safety have been previously reported only from clinical trials but no report exists about real-life experience.

Patient/methods

we describe three Italian children with nmDMD treated with ataluren for 1 year. Measurements were made every 3 months and was evaluated the 6-Minute Walking Distance (6MWD).

Results

Case1 involves a patient with a 6MWD at T0 of 360 m, who started ataluren therapy at age 10 years. Case2 is a child who began treatment with ataluren at age 8 years when he had severe ambulatory compromise (6MWD < 75 m at T0). A third patient (case3) had a 6MWD of 320 m when he started ataluren therapy at age 5 years. The best improvement in 6MWD was observed in case3, a patient in whom treatment with ataluren was started much earlier. In case1, ataluren was started relatively late and 6MWD was maintained at a stable level. Surprisingly, we observed a 50% improvement in 6MWD in case2, a patient who began therapy early, but with a severe loss of lower limb muscle function at the time.

Conclusions

treatment responses depend on the patient's age and disease severity when therapy was initiated. On the basis of our experience, the main factor that influences the effectiveness seems to be earlier instigation of therapy and positive results may still be achieved in patients with more severe muscle involvement. Interestingly, these three boys with phenotypically different nmDMD provide useful information regarding future therapeutic recommendations for the ataluren administration in real clinical practice.

Pragmatic abilities in multiple sclerosis: The contribution of the temporo-parietal junction

Recent studies showed that multiple sclerosis (MS) patients might experience communicative deficits, specifically in pragmatics (i.e., the ability to integrate the context-dependent aspects of language). A crucial region for pragmatics is the temporo-parietal junction, in particular the so-called Geschwind's area (GA), which is involved in high-level language processes, including the comprehension of narratives, metaphor, and irony. We evaluated the relationship between pragmatic abilities, measured through the Assessment of Pragmatic Abilities and Cognitive Substrates (APACS) test, and the functional connectivity (FC) of the bilateral GAs, assessed through a seed-based analysis of Resting-State fMRI in patients with MS. A positive correlation was observed between APACS scores and the FC for both the right and the left GA and the paracingulate cortex. Our findings suggest that the brain FC for social communication involves connections extending over both hemispheres, including right and left GAs and right and left paracingulate cortex, possibly impaired in patients with MS. This study offers preliminary evidence for future researches enrolling also a control sample to explore the involvement of GA in pragmatics in neurological disorders as well as in healthy conditions.

The therapeutic use of non-invasive brain stimulation in multiple sclerosis - a review

BACKGROUND

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system and a leading cause of disability in young adults. Many disabling symptoms in MS, such as spasticity, pain, depression and cognitive deficits are not fully controlled by drug treatment. Non-invasive brain stimulation (NIBS) techniques can be used as tools for modulating altered cortical excitability and plasticity MS patients, providing an improvement in disabling symptoms affecting such patients.

OBJECTIVE

This review reported and summarized some of the most interesting and promising recent achievements regarding the therapeutic use of NIBS in MS patients.

METHODS

We reviewed the clinical application of transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS), emphasizing their effect on clinical symptoms and signs that are commonly involved in MS patients. In addition, we shortly described new NIBS protocols, such as transcranial alternating current stimulation and transcranial focused ultrasound stimulation as potential and innovative therapeutic options to be applied in future studies in MS patients.

RESULTS

We reviewed twenty-one studies covering six main clinical domains. Most of such studies focused on fatigues (33.3%), motor performance (19%) and spasticity (19%), sparse results were about pain (9.5%), cognitive abilities (9.5%), sensory deficit (4.8%) and bladder function (4.8%). The most promising results have been published for the improvement of motor (i.e. hand dexterity) and cognitive performances (i.e. attention and working memory) by applying rTMS or tDCS alone or in association with motor/cognitive training, for pain's treatment by using tDCS.

CONCLUSION

There are still no official recommendations for the therapeutic use of tDCS or rTMS in MS. The huge inter-individual variability of NIBS efficacy is still a big challenge which needs to be solved. However, well-designed studies, deeper knowledge about pathomechanisms underlying MS, and the combination of such techniques with motor and cognitive rehabilitation might results in higher effectiveness of NIBS.

Loss of cutaneous large and small fibers in naive and l-dopa-treated PD patients

OBJECTIVE

To study small and large fiber pathology in drug-naive and l-dopa-treated patients affected by Parkinson disease (PD) in early phases, before the occurrence of neuropathic electrophysiologic abnormalities.

METHODS

We enrolled 85 patients with idiopathic PD (male/female 49/36, age 61.3 ± 9.7 years) without electrophysiologic signs of neuropathy, including 48 participants naive to l-dopa treatment. All patients underwent clinical, functional, and morphologic assessment of sensory and autonomic nerves through dedicated questionnaires, quantitative sensory testing, sympathetic skin response, dynamic sweat test, and punch biopsies from glabrous and hairy skin. Sensory and autonomic innervation was visualized with specific antibodies and analyzed by confocal microscopy. Data were compared with those obtained from sex- and age-comparable healthy controls. In 35 patients, skin biopsies were performed bilaterally to evaluate side-to-side differences.

RESULTS

Intraepidermal nerve fiber density was lower in patients compared to controls in all the examined sites (p < 0.001). The loss was higher in the more affected side (p < 0.01). A loss of autonomic nerves to vessels, sweat glands, and arrector pili muscles and of Meissner corpuscles and their myelinated endings in glabrous skin was found (p < 0.001). Patients showed increased tactile and thermal thresholds, impairment of mechanical pain perception, and reduced sweat output (p < 0.001). The naive and l-dopa-treated groups differed only for Meissner corpuscle density (p < 0.001).

CONCLUSIONS

Both large and small fiber pathology occurs in the early stages of PD and may account for the sensory and autonomic impairment. l-Dopa affects the 2 populations of fibers differently.

The hidden Niemann-Pick type C patient: clinical niches for a rare inherited metabolic disease

BACKGROUND

Niemann-Pick disease type C (NP-C) is a rare, inherited neurodegenerative disease of impaired intracellular lipid trafficking. Clinical symptoms are highly heterogeneous, including neurological, visceral, or psychiatric manifestations. The incidence of NP-C is under-estimated due to under-recognition or misdiagnosis across a wide range of medical fields. New screening and diagnostic methods provide an opportunity to improve detection of unrecognized cases in clinical sub-populations associated with a higher risk of NP-C. Patients in these at-risk groups ("clinical niches") have symptoms that are potentially related to NP-C, but go unrecognized due to other, more prevalent clinical features, and lack of awareness regarding underlying metabolic causes.

METHODS

Twelve potential clinical niches identified by clinical experts were evaluated based on a comprehensive, non-systematic review of literature published to date. Relevant publications were identified by targeted literature searches of EMBASE and PubMed using key search terms specific to each niche. Articles published in English or other European languages up to 2016 were included.

FINDINGS

Several niches were found to be relevant based on available data: movement disorders (early-onset ataxia and dystonia), organic psychosis, early-onset cholestasis/(hepato)splenomegaly, cases with relevant antenatal findings or fetal abnormalities, and patients affected by family history, consanguinity, and endogamy. Potentially relevant niches requiring further supportive data included: early-onset cognitive decline, frontotemporal dementia, parkinsonism, and chronic inflammatory CNS disease. There was relatively weak evidence to suggest amyotrophic lateral sclerosis or progressive supranuclear gaze palsy as potential niches.

CONCLUSIONS

Several clinical niches have been identified that harbor patients at increased risk of NP-C.

Upper motor neuron evaluation in multiple sclerosis patients treated with Sativex®

BACKGROUND

Spasticity in multiple sclerosis (MS) results from an imbalance of inputs from descending pathways to the spinal motor circuits, as well as from a damage of the corticospinal tract (CST).

OBJECTIVES

To assess CST impairment in MS patients with and without spasticity and to evaluate its evolution under Sativex^® treatment.

METHODS

Ten MS patients with spasticity ("cases") underwent clinical (EDSS, 9-hole Peg, Ashworth scale, Timed 25-Foot Walk, and NRS for spasticity), MRI (CST fractional anisotropy [FA]), and electrophysiological (central motor conduction time [CMCT] and H/M ratio) evaluations at baseline and after 12 months. We selected 20 MS patients without spasticity as control group at baseline.

RESULTS

At baseline, cases showed a lower CST FA (0.492±0.045 vs 0.543±0.047; P=.01) and a higher CMCT (P=.001) compared to the control group. No correlations were found between clinical, electrophysiological, and MRI features. After 12 months, cases showed a decrease in non-prevalent degree of impairment (PDI) side FA (0.502±0.023 vs 0.516±0.033; P=.01) without differences for electrophysiological features compared to baseline. Treatment with Sativex^® resulted in a reduction of NRS for spasticity (P=.01).

CONCLUSIONS

We confirm the presence of CST impairment in MS patients with spasticity. We did not identify structural/electrophysiological correlates that could explain Sativex^® clinical effect.

Postural instability in Charcot-Marie-Tooth 1A disease

The aim of this study was to evaluate the influence of somatosensory impairment, distal muscle weakness and foot deformities on the balance in 21 CMT1A patients using a baropodometric platform. Stabilometric analysis by measuring sway area and velocity of a centre of pressure (CoP) both at open and closed eyes were used to assess postural imbalance. Static analysis, by measuring the load and the plantar surface of forefoot, midfoot and hindfoot was used to define the footprint shape and to assess as a whole foot deformities. Stabilometric and static results were compared with those of a control group. In CMT1A patients, stabilometric findings were correlated with static parameters, Achilles' tendon retraction, distal muscle strength and CMT examination score (CMTES). CMT1A patients compared to controls had lower plantar surface and load on midfoot, and higher load on a forefoot. CMT1A patients had a greater postural instability, since they had a higher CoP velocity, both at open and closed eyes. Moreover, the CoP velocity correlated inversely with the strength of ankle dorsi-flexion muscles and directly with CMTES as whole and with the item "motor symptoms legs". Postural imbalance was not correlated with sensory impairment and foot deformities as expressed by static analysis and Achilles' tendon retraction. In this study we demonstrated an altered balance in CMT1A patients during upright standing. The imbalance in our CMT patients seems to be related to the weakness of ankle dorsi-flexor muscles rather than sensory impairment or foot deformities. These results could be due to a mildly affected CMT1A population, evaluated in an early stage of the disease.

Muscle fiber type disproportion (FTD) in a family with mutations in the LMNA gene

INTRODUCTION

Mutations in the lamin A/C protein cause laminopathies, a heterogeneous group of disorders that include recessive axonal neuropathy (CMT2B1), Emery-Dreifuss muscular dystrophy (EDMD), limb-girdle muscular dystrophy (LGMD), dilated cardiomyopathy with conduction defect, and different forms of lipodystrophy and progeria.

METHODS

We provide clinical, histopathological, muscle imaging, and cardiac features of a family with heterozygous mutation in the LMNA gene.

RESULTS

We identified heterozygous mutations (c.80C> T; pT27I) in the LMNA gene in 3 family members who had the LGMD phenotype with onset in their early thirties and cardiac conduction defects or dilated cardiomyopathy. Interestingly, muscle biopsies showed changes consistent with fiber type disproportion (FTD).

CONCLUSIONS

Fiber type disproportion has been reported only anecdotally in muscle biopsies of patients with LMNA mutations. Our report further supports this association and suggests inclusion of molecular testing for LMNA in the differential diagnosis of myopathies with FTD due to the risk for life threatening events.

Small nerve fiber involvement in CMT1A

OBJECTIVE

To assess the involvement of small nerve fibers in Charcot-Marie-Tooth type 1A (CMT1A).

METHODS

We used indirect immunofluorescence and confocal microscopy on punch biopsies from glabrous (fingertip) and hairy (thigh and leg) skin of 20 unrelated patients with CMT1A to quantify somatic and autonomic nerve fibers. In particular, we quantified epidermal nerve fibers (ENF), Meissner corpuscles (MC), intrapapillary myelinated endings (IME), and sudomotor nerves. We correlated morphologic data with findings from quantitative sensory testing, sudomotor output, sympathetic skin response, and cardiovascular reflexes. A control population of healthy age- and sex-matched controls was included with a matching ratio of 1:2.

RESULTS

We found a length-dependent loss of ENFs that worsened with aging. We also observed a loss of MCs, IMEs, and sudomotor nerves. The loss of ENF at distal leg correlated with the increase in heat-pain thresholds (p < 0.05) and with tactile thresholds (p < 0.05). Sudomotor nerve fiber loss correlated with ENF density (p < 0.05) and sweating output (p < 0.001).

CONCLUSIONS

We demonstrated through morphologic, physical, and psychophysical testing that small somatic and autonomic fibers are abnormal and cause symptoms in patients with CMT1A. Awareness of such symptoms by the clinician could lead to better treatment.

Charcot-Marie-Tooth disease: frequency of genetic subtypes in a Southern Italy population

The objective of this study is to assess the genetic distribution of Charcot-Marie-Tooth (CMT) disease in Campania, a region of Southern Italy. We analyzed a cohort of 197 index cases and reported the type and frequency of mutations for the whole CMT population and for each electrophysiological group (CMT1, CMT2, and hereditary neuropathy with susceptibility to pressure palsies [HNPP]) and for familial and isolated CMT cases. Genetic diagnosis was achieved in 148 patients (75.1%) with a higher success rate in HNPP and CMT1 than CMT2. Only four genes (PMP22, GJB1, MPZ, and GDAP1) accounted for 92% of all genetically confirmed CMT cases. In CMT1, PMP22 duplication was the most common mutation while the second gene in order of frequency was MPZ in familial and SH3TC2 in isolated cases. In CMT2, GJB1 was the most frequent mutated gene and GJB1 with GDAP1 accounted for almost 3/4 of genetically defined CMT2 patients. The first gene in order of frequency was GJB1 in familial and GDAP1 in isolated cases. In HNPP, the majority of patients harbored the PMP22 gene deletion. The novelty of our data is the relatively high frequency of SH3TC2 and GDAP1 mutations in demyelinating and axonal forms, respectively. These epidemiological data can help in panel design for our patients' population.

Central cholinergic dysfunction in the adult form of Niemann Pick disease type C: a further link with Alzheimer's disease?

Adult patients with Niemann-Pick disease type C (NPC) usually develop cognitive impairment progressing to dementia, whose pathophysiology remains still unclear. Noteworthy parallels exist in cognitive impairment and cellular pathology of NPC and Alzheimer's disease (AD). In particular, alterations of cholinergic system, which represent one of the pathological hallmarks and contribute to cognitive deterioration in AD, have recently been demonstrated in a human brain autopsy and in an experimental model of NPC. This finding raised the issue that central cholinergic circuits dysfunction may contribute to pathophysiology of cognitive impairment in NPC as well, and prompted us to evaluate the cholinergic functional involvement in NPC patients by applying a neurophysiologic technique, named short-latency afferent inhibition (SAI). We describe clinical, biochemical, molecular and neuropsychological features, and SAI findings in three patients affected by NPC. Diagnosis of NPC was assessed by molecular analysis of the NPC1 gene in all patients. In two of them, biochemical analysis of intracellular accumulation of unesterified cholesterol was also performed. The main clinical features were cerebellar ataxia, vertical supranuclear gaze palsy and a variable degree of cognitive impairment ranging from only memory impairment to severe dementia. Electrophysiological evaluation revealed a reduced SAI in all three patients. Our SAI findings provide evidence of cholinergic dysfunction in patients with the adult form of NPC, supporting that cholinergic alterations may play a role in cognitive impairment in NPC, and strengthening the similarities between NPC and AD.

A new Italian FHM2 family: clinical aspects and functional analysis of the disease-associated mutation

OBJECTIVE

To describe a new FHM kindred, and to analyse the functional consequences of the disease-associated ATP1A2 p.G301R mutation in human cellular models grown at 37°C.

PATIENTS AND METHODS

Seven patients were clinically evaluated and gave informed consent for molecular analysis. Extra-pyramidal rigidity of the limbs was present in four subjects and in three of them tongue apraxia was also observed. ATP1A2 and CACNA1A were analysed by direct sequencing. Functional consequences of the mutation were investigated by cell viability assays, Western blots, and immunocytochemistry. Three-dimensional models of the human Na(+)/K(+)-ATPase α2 subunit were generated by homology modelling using SWISS-MODEL.

FINDINGS

Analysis of ATP1A2 showed a heterozygous mutation, c.901G>A predicting the replacement of arginine for glycine at residue 301 (p.G301R). Functional analysis suggested that the mutation completely abolished Na(+)/K(+)-ATPase function.

CONCLUSIONS

The phenotypic spectrum of our FHM2 family includes some peculiar features. Functional data confirm that Na(+)/K(+)-ATPase haploinsufficiency caused by the ATP1A2 p.G301R mutation is responsible for FHM in the described family.

Electrophysiological characterisation in hereditary spastic paraplegia type 5

OBJECTIVE

To assess in SPG5 hereditary spastic paraparesis (HSP) the involvement of the central (CNS) and the peripheral (PNS) nervous system by a multimodal electrophysiological approach.

METHODS

Four patients belonging to three HSP families, with a molecular diagnosis of SPG5, underwent electrophysiological evaluation including electromyography (EMG) and nerve conduction study (NCS), motor-evoked potentials (MEPs) by transcranial magnetic stimulation (TMS) and somatosensory evoked potentials (SEPs) at upper and lower limbs, visual (VEPs) and brainstem auditory evoked potentials (BAEPs). In one patient, electrophysiological evaluation was performed twice at the age of 12 and 31 years.

RESULTS

EMG and NCS were normal. MEPs and SEPs were abnormal in all patients along the central pathway for upper and/or lower limbs. VEPs revealed a damage of visual pathway and BAEPs showed the involvement of auditory pathway within the brainstem. In the patient who underwent electrophysiological follow-up, MEP and SEP findings were unmodified, whereas VEPs showed no reproducible responses.

CONCLUSIONS

We report an extensive electrophysiological evaluation of SPG5 and we confirm that the SPG5 phenotype may be broader than pure presentation.

SIGNIFICANCE

Electrophysiological evaluation, showing diffuse CNS involvement with PNS sparing, could be very useful to address the molecular diagnosis and to follow-up a hypothetical treatment.

Functional involvement of central cholinergic circuits and visual hallucinations in Parkinson's disease

Visual hallucinations (VHs) represent a frequent and disturbing complication of Parkinson's disease. Evidence suggests that VH can be related to central cholinergic dysfunction. Short-latency afferent inhibition (SAI) technique gives the opportunity to test an inhibitory cholinergic circuit in the human cerebral motor cortex. This inhibition of motor-evoked potentials can be observed when transcranial magnetic stimulation is delivered with a delay ranging from 2 to 8 ms, after a peripheral nerve afferent input has reached the somatosensory cortex. We applied SAI technique in 10 non-demented patients with Parkinson's disease with VHs, in 12 non-demented patients with Parkinson's disease without VHs (NVH-pts) and in 11 age-matched normal controls. All patients with Parkinson's disease underwent a battery of neuropsychological tests to assess frontal and visuospatial functions, memory and attention. SAI was significantly reduced in patients with VHs compared with controls and patients without VHs. Neuropsychological examination showed a mild cognitive impairment in 16 out of 22 patients with Parkinson's disease. In addition, we found that in our patients with VHs, performance of some tasks evaluating visuospatial functions and attentional/frontal lobe functions was significantly more impaired than in patients without VHs. SAI abnormalities, presence of VH and neuropsychological results strongly support the hypothesis of cholinergic dysfunction in some patients with Parkinson's disease, who will probably develop a dementia. A follow-up study of our patients is required to verify whether SAI abnormalities can predict a future severe cognitive decline. Moreover, SAI can also be very useful to follow-up the efficacy of anti-cholinesterase therapies.

Recurrent pulmonary and cerebral thromboembolism in an adult patients following incomplete removal of ventriculoatrial shunt for congenital hydrocephalus

A 34-year-old man was admitted to our hospital's department of neurology because he had experienced a cryptogenic stroke followed by a transient ischaemic attack. The patient suffered from congenital hydrocephalus which was treated by ventriculoatrial shunt at 8 months of age. Twelve months later, because of recurrent infections, the catheter was partially removed and the distal segment was left in place. At admission, the transoesophageal echocardiogram showed severe pulmonary hypertension (80 mm Hg confirmed by invasive measurement). The distal tip of the catheter had migrated into the left atrium through a patent foramen ovale inducing a massive right-to-left shunt. We surgically removed the catheter and closed the interatrial defect. At 1 and 6 months follow-up the patient was asymptomatic with a reduced pulmonary hypertension (50 mm Hg). Since there was no other clinical finding responsible for the recurrent thromboembolic events, both at the pulmonary and cerebral level, the catheter was removed to prevent further complications.

Case of acute motor conduction block neuropathy (AMCBN)

We describe a 21 year-old man with an acute development of weakness whose clinical and serial electrophysiological findings were atypical for Guillain-Barré syndrome. Electrophysiological data suggested a diagnosis of "acute motor conduction block neuropathy" (AMCBN). The 6 months of disease duration and the electrophysiological follow-up, which never showed axonal degeneration until complete clinical recovery, raise the issue of the relationship between AMCBN and acute motor axonal neuropathy (AMAN).