Primary Lateral Sclerosis Patients Research Articles

Upper motor neuron signs in primary lateral sclerosis and hereditary spastic paraplegia.

The frequency and distribution of upper motor neuron (UMN) signs in primary lateral sclerosis (PLS) are unknown. We aimed to study the spectrum of UMN signs in PLS and compare it with hereditary spastic paraplegia (HSP). We retrospectively analyzed the frequency of different UMN signs, including hyperreflexia (limbs and jaw), limb and tongue spasticity, Babinski, and Hoffman signs, in PLS patients at first observation and compared this respect to onset region and symptom duration. We also compared PLS versus HSP patients. We included 34 PLS and 20 HSP patients, with a median symptom duration at first visit of 3.0 (interquartile range, IQR = 4.0) and 19.0 (IQR = 22.0) years, respectively. In PLS patients, hyperreflexia of upper (UL) (88.2%) and lower (LL) (91.2%) limbs, and LL spasticity (79.4%) were the most common findings. Spasticity of LL was significantly (p = .012) more frequent in LL-spinal onset subgroup, tongue spasticity in bulbar-onset subgroup (p = .021), and Hoffman sign in UL-spinal onset subgroup (p = .024). The PLS subgroup with shorter disease duration had a higher frequency of abnormal jaw jerk reflex (p = .037). Compared with HSP, PLS patients had a higher frequency of UL hyperreflexia (88.2% vs. 42.1%, p < .001) and UL spasticity (44.1% vs. 0.0%, p < .001). Asymmetric distribution of UMN signs was present in PLS and not in HSP. In PLS, UL UMN signs are nearly always present and UMN sign distribution appears to be associated with onset region. At first observation, bulbar involvement, asymmetrical distribution of UMN signs and UL spasticity may indicate PLS versus HSP.

Mills’ Disease Variant (P3-8.012)

Mills’ Disease Variant (P3-8.012)

M1/precuneus ratio as a surrogate marker of upper motor neuron sign in ALS

ObjectiveTo investigate whether primary motor cortex (M1) volume measured with an automated approach in MRI reflects upper motor neuron dysfunction and whether it can serve as a potential diagnostic and/or disease-tracking biomarker for amyotrophic lateral sclerosis (ALS). MethodsIn this retrospective study, we enrolled 95 subjects, including 33 possible or laboratory supported probable ALS, 26 probable or definite ALS (Prob/Def), 2 primary lateral sclerosis patients, 8 progressive muscular atrophy patients, 19 normal controls (NC) and 7 ALS patients having a second structural MRI scan. Some subjects also underwent functional MRI. We calculated M1, primary sensory cortex, precuneus volumes, and total gray matter volume (TGMV) with FreeSurfer. The sensorimotor network (SMN) was identified using independent component analysis. ResultsThe M1/precuneus ratio showed a significant difference between the NC and Prob/Def groups (p < 0.05). The diagnostic accuracy of the M1/precuneus ratio was moderate for distinguishing Prob/Def from NC (cutoff = 1.00, sensitivity = 0.42, specificity = 0.90). Two of eight cases without upper motor neuron dysfunction could be diagnosed with ALS using M1/precuneus ratio as a surrogate marker. A negative correlation between M1/precuneus ratio and functional activity was found in Brodmann area 6 in the SMN in all subjects. TGMV tended to decrease with disease progression (p = 0.04). InterpretationThe M1/precuneus volume ratio, associated with the SMN, may have potential as a surrogate biomarker of upper motor neuron dysfunction in ALS. Furthermore, TGMV may serve as an ALS disease-tracking biomarker.

Parkinsonian Syndromes in Motor Neuron Disease: A Clinical Study.

BackgroundParkinsonian syndromes may rarely occur in motor neuron disease (MND). However, previous studies are heterogeneous and mostly case reports or small case series. Therefore, we aimed to identify and characterize patients with concurrent parkinsonian syndromes extracted from a cohort of 1,042 consecutive cases diagnosed with MND at a tertiary Italian Center.MethodsDiagnosis of Parkinson's disease (PD), progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS) was made according to current criteria. Clinical characterization included: upper and lower motor neuron disease features, typical and atypical parkinsonian features, oculomotor disorders, cognitive testing, MRI features, and, when available molecular neuroimaging. Genetic testing was carried out for major MND and PD-associated genes.ResultsParkinsonian syndromes were diagnosed in 18/1042 (1.7%) of MND patients (7 PD, 6 PSP, 3 CBS, 2 other parkinsonisms). Based on phenotype, patients could be categorized into amyotrophic lateral sclerosis (ALS)-parkinsonism and primary lateral sclerosis (PLS)-parkinsonism clusters. Across the whole database, parkinsonism was significantly more common in PLS than in other MND phenotypes (12.1 vs. 1.1%, p = 5.0 × 10−10). MND patients with parkinsonian features had older age of onset, higher frequency of oculomotor disorders, cognitive impairment, and family history of parkinsonism or dementia. Two patients showed pathogenic mutations in TARDBP and C9orf72 genes.ConclusionSpecific patterns in MND-parkinsonism were observed, with PLS patients often showing atypical parkinsonian syndromes and ALS patients more frequently showing typical PD. Systematic clinical, genetic, and neuropathologic characterization may provide a better understanding of these phenotypes.

Iron-sensitive MR imaging of the primary motor cortex to differentiate hereditary spastic paraplegia from other motor neuron diseases.

Hereditary spastic paraplegia (HSP) is a group of genetic neurodegenerative diseases characterised by upper motor neuron (UMN) impairment of the lower limbs. The differential diagnosis with primary lateral sclerosis (PLS) and amyotrophic lateral sclerosis (ALS) can be challenging. As microglial iron accumulation was reported in the primary motor cortex (PMC) of ALS cases, here we assessed the radiological appearance of the PMC in a cohort of HSP patients using iron-sensitive MR imaging and compared the PMC findings among HSP, PLS, and ALS patients. We included 3-T MRI scans of 23 HSP patients, 7 PLS patients with lower limb onset, 8 ALS patients with lower limb and prevalent UMN onset (UMN-ALS), and 84 ALS patients with any other clinical picture. The PMC was visually rated on 3D T2*-weighted images as having normal signal intensity, mild hypointensity, or marked hypointensity, and differences in the frequency distribution of signal intensity among the diseases were investigated. The marked hypointensity in the PMC was visible in 3/22 HSP patients (14%), 7/7 PLS patients (100%), 6/8 UMN-ALS patients (75%), and 35/84 ALS patients (42%). The frequency distribution of normal signal intensity, mild hypointensity, and marked hypointensity in HSP patients was different than that in PLS, UMN-ALS, and ALS patients (p < 0.01 in all cases). Iron-sensitive imaging of the PMC could provide useful information in the diagnostic work - up of adult patients with a lower limb onset UMN syndrome, as the cortical hypointensity often seen in PLS and ALS cases is apparently rare in HSP patients. • The T2* signal intensity of the primary motor cortex was investigated in patients with HSP, PLS with lower limb onset, and ALS with lower limb and prevalent UMN onset (UMN-ALS) using a clinical 3-T MRI sequence. • Most HSP patients had normal signal intensity in the primary motor cortex (86%); on the contrary, all the PLS and the majority of UMN-ALS patients (75%) had marked cortical hypointensity. • The T2*-weighted imaging of the primary motor cortex could provide useful information in the differential diagnosis of sporadic adult-onset UMN syndromes.

Acoustic Change Over Time in Spastic and/or Flaccid Dysarthria in Motor Neuron Diseases

This study aims to investigate acoustic change over time as biomarkers to differentiate among spastic-flaccid dysarthria associated with amyotrophic lateral sclerosis (ALS), spastic dysarthria associated with primary lateral sclerosis (PLS), flaccid dysarthria associated with spinal and bulbar muscular atrophy (SBMA), and to explore how these acoustic parameters are affected by dysarthria severity. Thirty-three ALS patients with mixed flaccid-spastic dysarthria, 17 PLS patients with pure spastic dysarthria, 18 SBMA patients with pure flaccid dysarthria, and 70 controls, all French speakers, were included in the study. Speakers produced vowel-glide sequences targeting different vocal tract shape changes. The mean and coefficient of variation of the total squared change of mel frequency cepstral coefficients were used to capture the degree and variability of acoustic changes linked to vocal tract modifications over time. Differences in duration of acoustic events were also measured. All pathological groups showed significantly less acoustic change compared to controls, reflecting less acoustic contrast in sequences. Spastic and mixed spastic-flaccid dysarthric speakers showed smaller acoustic changes and slower sequence production compared to flaccid dysarthria. For dysarthria subtypes associated with a spastic component, reduced degree of acoustic change was also associated with dysarthria severity. The acoustic parameters partially differentiated among the dysarthria subtypes in relation to motor neuron diseases. While similar acoustic patterns were found in spastic-flaccid and spastic dysarthria, crucial differences were found between these two subtypes relating to variability. The acoustic patterns were much more variable in ALS. This method forms a promising clinical tool as a diagnostic marker of articulatory impairment, even at mild stage of dysarthria progression in all subtypes.

Does limited EMG denervation in early primary lateral sclerosis predict amyotrophic lateral sclerosis?

Objective: We assessed whether a cohort of patients with primary lateral sclerosis (PLS) and limited electromyography (EMG) motor unit denervation changes evolve into amyotrophic lateral sclerosis (ALS) with prolonged follow-up. Methods: We initially ascertained all PLS patients diagnosed at Mayo Clinic-Rochester (1990–2016). Of 64 total cases, 43 had normal EMGs (“pure” PLS) during the first 4 years after symptom onset and were the focus of a prior publication, documenting absence of evolution to ALS. The remaining 21 patients had limited motor unit changes on EMG needle examination (denervation and most with fibrillation or fasciculation potentials) but insufficient to raise a strong suspicion of ALS; these 21 patients were followed to determine whether they evolved into ALS. Results: Of these 21 patients, the median follow-up was 7 years’ disease duration (range: 4–27 years; IQR 5–8.5). They included 11 females (52%) with median onset-age of 57 years (range: 42–72 years). Two patients (10%) subsequently met revised El Escorial criteria for ALS after 7 and 13 years, respectively. The remainder had stable EMG changes with a persistent PLS phenotype. Among these remaining 19 patients, the PLS course was somewhat more aggressive than our previously reported series of 43 patients devoid of EMG denervation. The paraparetic variant was more common than the hemiparetic and bulbar variants, similar to “pure” PLS. Conclusions: Among PLS patients with definite but limited EMG denervation, 2/21 (10%) later developed ALS. The patients in this series had a more progressive clinical course compared to our previously reported pure PLS cases.

Electromyographic findings in primary lateral sclerosis during disease progression

ObjectiveTo characterize electromyographic (EMG) findings in patients with primary lateral sclerosis (PLS) during the disease course. MethodsIn PLS patients we scored spontaneous activity and motor unit action potential (MUP) pattern on EMG. We compared patients according to lower (group A) and higher (group B) EMG scores. EMG studies were repeated at intervals longer than 11 months; two or three repeat studies were required for inclusion in the analysis. ResultsWe studied 22 patients. Fasciculation potentials were found in 13 and fibrillations/positive sharp waves (fibs/sw) in 3 patients. Both were stable over time. Most patients had MUP abnormalities (n = 17), with worsening in the lower limbs in patients with three evaluations (p = 0.010). Compared to group A (n = 12), patients of group B (n = 10) had a significant shorter disease duration (median 10.9 vs 15.2 years, p < 0.001), lower functional score at both first (39 vs 45, p = 0.034) and last (29 vs 38, p = 0.003) evaluations, and had a faster functional decline (0.19 vs 0.08, p = 0.004). ConclusionsMost PLS patients showed minor and stable EMG abnormalities, without progression to ALS. Patients with more EMG abnormalities have a faster progression. SignificanceEMG abnormalities in most PLS patients are minor and stable.

Propagation patterns in motor neuron diseases: Individual and phenotype-associated disease-burden trajectories across the UMN-LMN spectrum of MNDs

Motor neuron diseases encompass a divergent group of conditions with considerable differences in clinical manifestations, survival, and genetic vulnerability. One of the key aspects of clinical heterogeneity is the preferential involvement of upper (UMN) and lower motor neurons (LMN). While longitudinal imaging patters are relatively well characterized in ALS, progressive cortical changes in UMN,- and LMN-predominant conditions are seldom evaluated. Accordingly, the objective of this study is the juxtaposition of longitudinal trajectories in 3 motor neuron phenotypes; a UMN-predominant syndrome (PLS), a mixed UMN-LMN condition (ALS), and a lower motor neuron condition (poliomyelitis survivors). A standardized imaging protocol was implemented in a prospective, multi-timepoint longitudinal study with a uniform follow-up interval of 4 months. Forty-five poliomyelitis survivors, 61 patients with amyotrophic lateral sclerosis (ALS), and 23 patients with primary lateral sclerosis (PLS) were included. Cortical thickness alterations were evaluated in a dual analysis pipeline, using standard cortical thickness analyses, and a z-score-based individualized approach. Our results indicate that PLS patients exhibit rapidly progressive cortical thinning primarily in motor regions; ALS patients show cortical atrophy in both motor and extra-motor regions, while poliomyelitis survivors exhibit cortical thickness gains in a number of cerebral regions. Our findings suggest that dynamic cortical changes in motor neuron diseases may depend on relative UMN and/or LMN involvement, and increased cortical thickness in LMN-predominant conditions may represent compensatory, adaptive processes.

Bradykinesia in motoneuron diseases

ObjectiveOnly few studies investigated voluntary movement abnormalities in patients with motoneuron diseases (MNDs) or their neurophysiological correlates. We aimed to kinematically assess finger tapping abnormalities in patients with amyotrophic lateral sclerosis (ALS) and primary lateral sclerosis (PLS), as compared to healthy controls (HCs), and their relationship with motoneuron involvement. MethodsFourteen ALS and 5 PLS patients were enrolled. Finger tapping was assessed by a motion analysis system. Patients underwent a central motor conduction time assessment, a motor nerve conduction study, and needle electromyography. Data were compared to those of 79 HCs using non-parametric tests. Possible relationships between clinical, kinematic, and neurophysiological data were assessed in patients. ResultsAs a major finding, ALS and PLS patients performed finger tapping slower than HCs. In both conditions, movement slowness correlated with muscle strength. In ALS, movement slowness also correlated with the amplitude of the compound muscle action potential recorded from the muscles involved in the task and with denervation activity. No correlations were found between slowness, measures of upper motoneuron involvement, and other clinical and neurophysiological data. ConclusionsThis study provides novel information on voluntary movement abnormalities in MNDs. SignificanceThe results highlight the pathophysiological role of motoneurons in generating movement slowness.

Combining structural and metabolic markers in a quantitative MRI study of motor neuron diseases.

ObjectiveTo assess the performance of a combination of three quantitative MRI markers (iron deposition, basal neuronal metabolism, and regional atrophy) for differential diagnosis between amyotrophic lateral sclerosis (ALS) and primary lateral sclerosis (PLS).MethodsIn total, 33 ALS, 12 PLS, and 28 healthy control (HC) subjects underwent a 3T MRI study including single‐ and multi‐echo sequences for gray matter (GM) volumetry and quantitative susceptibility mapping (QSM) and a pseudo‐continuous arterial spin labeling (ASL) sequence for cerebral blood flow (CBF) measurement. Mean values of QSM, CBF, and GM volumes were extracted in the motor cortex, basal ganglia, thalamus, amygdala, and hippocampus. A generalized linear model was applied to the three measures to binary discriminate between groups. The diagnostic performances were evaluated via receiver operating characteristic analyses.ResultsA significant discrimination was obtained: between ALS and HCs in the left and right motor cortex, where QSM increases were respectively associated with disability scores and disease duration; between PLS and ALS in the left motor cortex, where PLS patients resulted significantly more atrophic; between ALS and HC in the right motor cortex, where GM volumes were associated with upper motor neuron scores. Significant discrimination between ALS and HC was achieved in subcortical structures only combining all three parameters.InterpretationWhile increased QSM values in the motor cortex of ALS patients is a consolidated finding, combining QSM, CBF, and GM volumetry shows higher diagnostic potential for differentiating ALS patients from HC subjects and, in the motor cortex, between ALS and PLS.

Lipidomics study of plasma from patients suggest that ALS and PLS are part of a continuum of motor neuron disorders

Motor neuron disorders (MND) include a group of pathologies that affect upper and/or lower motor neurons. Among them, amyotrophic lateral sclerosis (ALS) is characterized by progressive muscle weakness, with fatal outcomes only in a few years after diagnosis. On the other hand, primary lateral sclerosis (PLS), a more benign form of MND that only affects upper motor neurons, results in life-long progressive motor dysfunction. Although the outcomes are quite different, ALS and PLS present with similar symptoms at disease onset, to the degree that both disorders could be considered part of a continuum. These similarities and the lack of reliable biomarkers often result in delays in accurate diagnosis and/or treatment. In the nervous system, lipids exert a wide variety of functions, including roles in cell structure, synaptic transmission, and multiple metabolic processes. Thus, the study of the absolute and relative concentrations of a subset of lipids in human pathology can shed light into these cellular processes and unravel alterations in one or more pathways. In here, we report the lipid composition of longitudinal plasma samples from ALS and PLS patients initially, and after 2 years following enrollment in a clinical study. Our analysis revealed common aspects of these pathologies suggesting that, from the lipidomics point of view, PLS and ALS behave as part of a continuum of motor neuron disorders.

Familial clustering of primary lateral sclerosis and amyotrophic lateral sclerosis: Supplementary evidence for a continuum.

Primary lateral sclerosis (PLS) is a motor neuron disorder characterized by a pure upper motor neuron degeneration in the bulbar and spinal regions. The key difference with amyotrophic lateral sclerosis (ALS) is the lower motor neuron system integrity. Despite important literature on this disease, the pathophysiology of PLS remains unknown, and the link with ALS still balances between a continuum and a separate entity from ALS. We report nine families in which both PLS and ALS cases occurred, in general among first-degree relatives. The patients with PLS and ALS had a typical disease presentation. Genetic studies revealed mutations in SQSMT1, TBK1, and TREM2 genes in two PLS patients and one ALS patient. These results strongly support a phenotypic continuum between PLS and ALS.

Extra-motor cerebral changes and manifestations in primary lateral sclerosis.

Primary lateral sclerosis (PLS) is classically considered a 'pure' upper motor neuron disorder. Motor cortex atrophy and pyramidal tract degeneration are thought to be pathognomonic of PLS, but extra-motor cerebral changes are poorly characterized. In a prospective neuroimaging study, forty PLS patients were systematically evaluated with a standardised imaging, genetic and clinical protocol. Patients were screened for ALS and HSP associated mutations, as well as C9orf72 hexanucleotide repeats. Clinical assessment included composite reflex scores, spasticity scales, functional rating scales, and screening for cognitive and behavioural deficits. The neuroimaging protocol evaluated cortical atrophy patterns, subcortical grey matter changes and white matter alterations in whole-brain and region-of-interest analyses. PLS patients tested negative for known ALS- and HSP-associated mutations and C9orf72 repeat expansions. Voxel-wise analyses revealed anterior cingulate, dorsolateral prefrontal, insular, opercular, orbitofrontal and bilateral mesial temporal grey matter changes and white matter alterations in the fornix, brainstem, temporal lobes, and cerebellum. Significant thalamus, caudate, hippocampus, putamen and accumbens nucleus volume reductions were also identified. Extra-motor clinical manifestations were dominated by verbal fluency deficits, language deficits, apathy and pseudobulbar affect. Our clinical and radiological evaluation confirms considerable extra-motor changes in a population-based cohort of PLS patients. Our data suggest that PLS should no longer be considered a neurodegenerative disorder selectively affecting the pyramidal system. PLS is associated with widespread extra-motor changes and manifestations which should be carefully considered in the multidisciplinary management of this low-incidence condition.

The NEALS primary lateral sclerosis registry

Background and objective Primary lateral sclerosis (PLS) is a neurodegenerative disease characterized by progressive upper motor neuron dysfunction. Because PLS patients represent only 1 to 4% of patients with adult motor neuron diseases, there is limited information about the disease’s natural history. The objective of this study was to establish a large multicenter retrospective longitudinal registry of PLS patients seen at Northeast ALS Consortium (NEALS) sites to better characterize the natural progression of PLS. Methods: Clinical characteristics, electrophysiological findings, laboratory values, disease-related symptoms, and medications for symptom management were collected from PLS patients seen between 2000 and 2015. Results: The NEALS registry included data from 250 PLS patients. Median follow-up time was 3 years. The mean rate of functional decline measured by ALSFRS-R total score was −1.6 points/year (SE:0.24, n = 124); the mean annual decline in vital capacity was −3%/year (SE:0.55, n = 126). During the observational period, 18 patients died, 17 patients had a feeding tube placed and 7 required permanent assistive ventilation. Conclusions: The NEALS PLS Registry represents the largest available aggregation of longitudinal clinical data from PLS patients and provides a description of expected natural disease progression. Data from the registry will be available to the PLS community and can be leveraged to plan future clinical trials in this rare disease.

Imaging and clinical data indicate considerable disease burden in 'probable' PLS: Patients with UMN symptoms for 2-4 years.

Primary lateral sclerosis (PLS) is an adult-onset upper motor neuron disease manifesting in progressive spasticity and gradually resulting in considerably motor disability. In the absence of early disease-specific diagnostic indicators, the majority of patients with PLS face a circuitous diagnostic journey. Until the recent publication of consensus diagnostic criteria, 4-year symptom duration was required to establish the diagnosis. The new diagnostic criteria introduced the category of ‘probable PLS’ for patients with a symptom duration of 2–4 years. “Evolving diagnostic criteria in primary lateral sclerosis: The clinical and radiological basis of "probable PLS" [1]. This dataset provides radiological metrics in a cohort of ‘probable PLS’ patients, ‘definite PLS’ patients and age-matched healthy controls. Region-of-interest radiological data include diffusivity metrics in the corticospinal tracts and corpus callosum as well as mean cortical thickness values in the pre- and para-central gyri in each hemisphere. Our data indicate considerable grey matter and relatively limited white matter involvement in ‘probable PLS’ which supports the rationale for this diagnostic category as a clinically useful entity. The introduction of this diagnostic category will likely facilitate the timely recruitment of PLS patients into research studies and pharmacological trials before widespread neurodegenerative change ensues.

Longitudinal evaluation of upper motor neuron burden scales in primary lateral sclerosis

Objective To assess whether published scales for measuring upper motor neuron burden (UMNB) show longitudinal change in patients with primary lateral sclerosis (PLS). Design: Retrospective calculation of three UMNB scales on a prospectively collected dataset from 53 patients with PLS enrolled in a longitudinal natural history study with at least 2 evaluation visits. UMNB scales were calculated according to their published descriptions. Non-linear trends over time of UMNB scale scores and slopes were calculated for each patient and correlations between UMNB scores and clinical measures were assessed. Results: All three UMNB scales exhibited increasing scores over the first 7.8 years of symptoms, with a flattening in slope after approximately 8 years. A scale used in imaging studies and the UPENN UMNS scale provided a better fit to the dataset than the MGH UMNB scale. All three UMNB scales exhibited moderate correlations with some clinical measures of movement, such as finger-tapping rate and timed gait. Correlations were strongest for the UPENN UMNS, which was also moderately correlated with the revised ALS functional rating scale. Conclusion: In a cohort of PLS patients enrolled in a natural history study, the three UMNB scales exhibited modest linear increases over the first 8 years of symptoms, followed by a plateau. Future clinical trials in PLS should consider stratification of patients by disease duration. UMNB scales may be useful secondary outcomes, but more sensitive primary outcome measures are needed for clinical trials for PLS.

Reliability of phrenic nerve conduction study: In healthy controls and in patients with primary lateral sclerosis

ObjectivePhrenic nerve conduction study is a marker of hypoventilation in amyotrophic lateral sclerosis. We aimed to evaluate its intra-rater reliability in healthy subjects and in a cohort of Primary Lateral Sclerosis (PLS) patients. MethodsEighteen healthy subjects and 16 PLS patients were included. All subjects underwent three phrenic nerve conduction evaluations (time interval: 1 week for healthy controls; 1 year for PLS patients). We analyzed intra-rater reliability for five parameters of the diaphragmatic motor response: latency; negative-peak duration, area and amplitude; peak-to-peak amplitude. ResultsHealthy subjects showed excellent inter-test reliability for most parameters (coefficients of variation <10%). In PLS patients coefficients of variation resulted <10% for latency and peak-to-peak amplitude, <20% for remaining parameters. Inter-test reliability was excellent for latency and peak-to-peak amplitude [intra-class correlation coefficient (ICC) > 0.9] and good for negative-peak amplitude and area (ICC 0.75 ≥ 0.9); duration was not reliable (ICC = 0.383). Negative peak and peak-to-peak amplitude had the least random error (respectively ±0.136 mV and ± 0.177 mV). All parameters showed homoscedasticity (R2 < 0.1). ConclusionsIntra-rater reliability is high for phrenic nerve study, especially for latency, peak-to-peak and negative-peak amplitude. SignificancePhrenic nerve conduction study is a reliable method to monitor respiratory function.

Focal alterations of the callosal area III in primary lateral sclerosis: An MRI planimetry and texture analysis.

The regional distribution of cerebral morphological alterations in primary lateral sclerosis (PLS) is considered to include the area III of the corpus callosum (CC). The study was designed to investigate regional white matter (WM) alterations in the callosal area III by T1 weighted magnetic resonance imaging (T1w-MRI) data in PLS patients compared with healthy controls, in order to identify atrophy and texture changes in vivo. T1w-MRI-based white matter mapping was used to perform an operator-independent CC-segmentation for the different areas of the CC in 67 PLS patients vs 82 matched healthy controls and vs 85 ALS patients. The segmentation was followed by texture analysis of the separated CC areas for the PLS patients vs controls and vs ALS patients. PLS was associated with significant atrophy in the area III of the CC (but not in the other callosal segments), while the alterations in the ALS patients were much more variable and were not significant at the group level. Furthermore, significant regional alterations of the texture parameters entropy and homogeneity in this area were shown in PLS patients and in ALS patients. This T1w-MRI study demonstrated focused regional CC atrophy and texture alterations limited to the callosal area III (which comprises fibers projecting into the primary motor cortices) in PLS, in comparison to a higher variability in CC size in ALS.

P69-S Cutaneous silent period behavior in different motor neuron diseases phenotypes

Background The cutaneous silent period (CSP) corresponds to a reduced electric activity of a contracting muscle, after electrical stimulation of sensory fibers. The afferent volley causes a presynaptic inhibition of spinal motor neurons (LMN) modulated by complex spinal circuits. CSP behavior in different motor neuron diseases (MND) phenotypes is unknown. Materials and methods We included 20 MND patients and 15 controls. CSP was obtained by applying electrical stimulation of the 5th finger. Surface EMG recordings were obtained from ADM muscle. CSP duration was defined by the time between a drop of rectified averaged EMG below 80%, and the final return above 80%, of baseline EMG. The mean duration was obtained from 10 consecutive curves obtained before and during co-contraction of the contralateral ADM muscle. Results MND patients had a median age of 59 years. 12 were diagnosed as amyotrophic lateral sclerosis (ALS), 6 as progressive muscular atrophy (PMA), 2 as primary lateral sclerosis (PLS). Median CSP duration was similar between controls and patients. During contralateral ADM contraction, CSP duration did not change in controls, patients with ALS and PMA, but decreased by 28% in PLS patients. Conclusions We present preliminary results suggesting that CSP behavior is not homogenous in different phenotypes of MND. We previously observed that reflex contralateral activation of the homonymous contralateral hand muscles is frequent in patients with PLS, indicating spinal cord hyperexcitability. Our CSP results suggest that this method can contribute to dissect the mechanisms underlying abnormal LMN excitability in patients with corticospinal tract lesion.