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Brain stem reflex abnormalities in patients with multiple sclerosis
No full textIntroduction: Patients with multiple sclerosis (MS) often exhibit a brainstem (BS) involvement, which is sometimes undetected by conventional investigation. Recently, the vestibulocollic reflex (VCR) has been widely used in MS to assess vestibulospinal pathways. Besides VCR, other myogenic potentials can be used to explore BS circuits. Among these, the trigeminocollic reflex (TCR) has never been systematically studied in MS, while the vestibulomasseteric (VMR) and acousticmasseteric (AMR) reflexes have never been investigated in neurological diseases.
Objectives: To perform a comprehensive evaluation of VMR, AMR, VCR and TCR in MS and compare frequency of abnormalities with those detected in controls; to correlate BSR data to those obtained from clinical examination, multimodal evoked potentials (EP) and conventional neuroimaging (MRI) assessment.
Methods: Sixty patients (33.3±8.3 years old) with diagnosis of relapsing-remitting MS and 60 age- and sex matched controls were studied. All participants underwent clinical examination and BSR recording. MS underwent additional mEP and MRI assessment. Group differences were tested with χ2 test and Mann-Whitney U test. Spearman’s rank correlation coefficient was used for correlation analysis.
Results: Patients had a mean illness duration of 8.2±6.4 years and EDSS score of 1.78±1.10 (with EDSS=0 in 15.3%). Neurological examination showed symptoms and/or signs of BS involvement in 37.3% of cases. The frequency of altered BSR was significantly different (p=0.00001) between controls and patients. In patients, the false negative fraction was 10% and the true positive fraction of having at least one, two, three or four altered reflexes was 90.0%, 73.3%, 50.0% and 15.0% respectively. The distribution of reflex alteration in the “altered” group of patients was the following: VMR and AMR were altered in 66.7% of cases, TCR in 63.3% and VCR in 31.7% of patients. As for the pattern of alteration, ranked as absence, delay and delay plus absence, the most represented alteration was the reflex absence. Overall, mEPs revealed BS abnormalities in 82.8% of patients. As for the pattern of EP alterations, absence was significantly (p<0.01) more frequent than delay. MRI detected BS lesions in 71.7% of patients (midbrain 53.3%, pons 95.3% and medulla 60.5%). Alterations of the whole BSR set correlated with: global EDSS score (p=0006), pyramidal signs and/or symptoms (p=0.01); alterations of the III-IV peak interval of the Brainstem Auditory EP (BAEP) (p=0.003) and of the p14 wave of the median Somatosensory Potential (mSEP) (p=0.003); lesion load in the whole BS (0=0.0001), pons (p=0.004) and medulla (p=0.018). AMR and VMR significantly correlated with III-IV BAEP peak interval (p=0.001) and mSEP p14 wave (p=0.007).
Conclusions: BSR-mEP correlations suggest that the combined use of this reflex battery may allow studying the BS level involved, with distinction of the medullo-spinal and medullo-pontine regions. The sensitivity of BSR set is comparable to that of mEP. The combination of these neurophysiological methods showed a high performance in spotting BS dysfunctions which were not clinically evident. The combined assessment of VMR, AMR, VCR and TCR may provide painless, easy to perform and low cost additional functional evaluation of BS integrity that may better assist conventional testing
Longitudinal assessment of brainstem reflexes in multiple sclerosis compared to multimodal evoked potentials, MRI and clinical evaluations
No full textQuestion: We have previously shown in patients with relapsing-remitting Multiple Sclerosis (MS) that: i) the
vestibulomasseteric (VMR), acousticmasseteric (AMR), trigeminocollic (TCR) and vestibulocollic (VCR) reflexes are
able to spot brainstem (BS) dysfunctions undetected by clinical and MRI examinations; ii) the combined use of these
Brainstem Reflexes (BSRs) with multimodal Evoked Potentials (EPs) is more valuable than each single test in the early
years after onset. Our aim was to document BS changes over time by BSRs, EPs, MRI and BS signs/symptoms (CLIN)
before and after at least one year follow up, in MS.
Methods: Forty-five MS patients (34.8±8.6 yrs old; disease duration 8.9±6.6 yrs) underwent BSRs, EPs (namely
Brainstem Auditory Evoked Potentials - BAEPs, median and tibial Somatosensory Evoked Potentials -mSEPs and
tSEPs), MRI and CLIN examination. BSR and EP data were ranked and summed up to obtain a cumulative score
expressing severity of neurophysiological impairment. Before-after changes were tested with Wilcoxon test.
Results: After 15.1±4.2 months from initial evaluation, no relapses had been reported by any patient. This was in line
with the stability of the frequency of CLIN and MRI abnormalities (37.3% and 71.1%, respectively) at the follow up.
Despite this, BSRs and EPs revealed a worsening of BS function. In particular, although the proportion of altered BSRs
did not change significantly (80.6% vs 90.3%; p=0.180), a significant worsening of scores was observed for VMR
(p=0.001), AMR (0.018) and TCR (p=0.013). Similarly to BSRs, the incidence rate of EP abnormalities did not increased
significantly (84.4% vs 86.7%, p=0.564), but the analysis of cumulative score showed a significant worsening for the
whole EP set (p=0.03) as well as for median SEP (68.9% vs 75.6%, p=0.03), P14 mSEP (33.3% vs 51.1%, p=0.005), tibial
SEP (60% vs 66.7%, p=0.03).
Conclusions: BSRs and EPs were able to reveal a significant worsening of BS functions in spite of any variation of
both BS signs/symptoms and of MRI BS lesion load. This is in agreement with previous reports on BSR/EP ability to
detect clinically and radiologically silent BS lesions. Further studies are needed in a larger cohort of patient to assess
BSR clinical usefulness in a longitudinal perspective
The N400 as electrophysiological marker of semantic incongruity in Mild Cognitive Impairment (MCI)
No full textMay ERP and SPECT investigations represent early markers of Mild Cognitive Impairment (MCI)
No full textL’onda P14 nello studio del tronco dell’encefalo (TE) in pazienti affetti da Sclerosi Multipla Recidivante-Remittente (SMRR).
No full textComparison of brainstem reflex recordings and evoked potentials with clinical and MRI data to assess brainstem dysfunction in multiple sclerosis: a short-term follow-up.
No full textBrainstem dysfunctions are associated to high risk of developing severe disability in patients with multiple sclerosis (PwMS), often undetected by conventional routine assessments. In this view, the purpose of this study was to monitor brainstem function over a short-term period in PwMS, comparing clinical and magnetic resonance imaging (MRI) examinations with evoked potentials (EPs) and brainstem reflexes (BSRs). Forty-five PwMS were evaluated at baseline and after 15.1 ± 4.2 months through Expanded Disability Status Scale (EDSS) score, MRI, EPs, vestibulo-masseteric (VMR), acoustic-masseteric (AMR), vestibulo-collic (VCR) and trigemino-collic (TCR) reflexes. At baseline, brainstem alterations were detected by EDSS, MRI, EPs and BSRs in 40, 77.8, 84.4 and 82.2 % of patients, respectively. At follow-up, EDSS and MRI remained unchanged, while EP and BSR deteriorated in 86.7 and 91.1 % of patients, respectively. Changes from 1 to 3 altered EPs and from 1 to 4 altered BSRs were significant only for EPs (p = 0.028). The analysis of grading severity for each test disclosed significant worsening of the VMR, AMR, TCR and P14 wave of the median somatosensory EP. Combined EP/BSR recordings were significantly more sensitive than paired EDSS/MRI assessments at baseline (93.3 versus 80 %; p = 0.006) and follow-up (97.8 versus 82.2 %; p = 0.008). In the short-term VMR, AMR, TCR and P14 wave disclosed a significant functional brainstem deterioration by detecting lesions that remained clinically and MRI silent. Our findings provide evidence for a valuable role of neurophysiological methods, especially BSRs, in investigating and monitoring brainstem dysfunctions in MS, in comparison with the standard clinical and MRI procedures
Exploring brainstem functions in MS patients by combining neurophysiological and neuroradiological approaches
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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