Comparison of brainstem reflex recordings and evoked potentials with clinical and MRI data to assess brainstem dysfunction in multiple sclerosis: a short-term follow-up.

Brainstem 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.

Vestibulo masseteric reflex and acoustic masseteric Reflex. Normative data and effects of age and gender.

OBJECTIVE: To provide normative data for the Vestibulo-Masseteric Reflex (VMR) and Acoustic-Masseteric Reflex (AMR) in healthy subjects, stratified for age and gender. METHODS: A total of 82 healthy subjects (M:F 43:39, mean age 39.3 ±â€¯18.4 years, range 13-79 years) underwent recording of click-evoked VMR and AMR (0.1 ms duration, 5 Hz frequency) from active masseter muscles. Masseter responses to uni- and bilateral stimulation were recorded in a zygomatic and a mandibular configuration, according to the position of the reference electrode. Stimulation intensity curves were recorded for each reflex in ten subjects (mean age 20.7 ±â€¯8.1 years). Gender effect was investigated in 62 subjects and age effect was analyzed in six 10-subject groups aged from <25 to >65 years. Onset and peak latencies, interpeak intervals, raw and corrected amplitudes, latency and amplitude asymmetries were analyzed. RESULTS: VMR had a higher elicitation rate than AMR. For both reflexes, rates of elicitation, and corrected amplitudes were higher in the zygomatic configuration, and bilateral stimulation elicited larger responses. Best acoustic ranges of elicitation were 98-113 dB for AMR and 128-138 dB for VMR. Reflex latencies were shorter in females than males. Frequency and amplitude of VMR and AMR decreased substantially over 55 year olds. CONCLUSIONS: VMR and AMR can be easily performed in any clinical neurophysiology laboratory. SIGNIFICANCE: These reflexes can find application in the investigation of brainstem function in central neurological disorders.

Cognitive impairment and neurophysiological correlates in MS.

Cognitive impairment in multiple sclerosis (MS) has received considerable interest over the last decades. Heterogeneous patterns of cognitive dysfunction have been reported in literature in relation to the subtype of the disease and the severity of specific cognitive domains affected. Event related potentials (ERPs), especially P300, have been employed to evaluate the cognitive decline in MS and neurophysiological findings agree with data obtained by neuropsychological testing. The objectivity, the reliability and the easy administration are the main features of ERP technique but more specific attention and memory tasks are needed to enhance the clinical value of the methodology. Moreover, ERP recording has the advantage of being feasible even in severe disabled patients. Finally, longitudinal ERP studies are required to investigate the natural course of cognitive dysfunction in MS, to estimate the prognostic value of subclinical defects in different clinical form of the disease and to evaluate clinical benefits of therapeutic and rehabilitative interventions.

Visual and auditory event-related potentials in sporadic amyotrophic lateral sclerosis.

OBJECTIVES: To investigate the relationship between amyotrophic lateral sclerosis (ALS) and cognitive function by means of oddball event-related potentials (ERPs) and to determine the usefulness of this methodology in the cognitive status assessment of physically disabled patients. METHODS: Visual and auditory oddball ERPs were recorded in 16 consecutive sporadic ALS patients. A comprehensive battery of neuropsychological (NP) tests assessed intelligence, executive functions, attention, memory, word fluency, visuo-motor and visual-constructive skills. RESULTS: All patients performed visual and auditory ERPs and 75% of cases showed abnormal N200 and/or P300 waves. Ten patients (62.5%) carried out the entire psychometric evaluation with significant impairment on tests of executive function and attention. A significant correlation between delayed visual (P<0.04) and auditory (P<0.04) P300 latency and impaired NP tests was found. CONCLUSIONS: In agreement with literature data, our findings confirm the hypothesis of cognitive impairment in ALS patients especially on attention and executive functions suggesting a more extensive degeneration beyond the motor areas. ALS causes severe physical disabilities and such a condition may interfere with NP testing. Thus, the P300 seems to be a useful tool for the assessment of cognition and attention when severe physical deficits are present.

Pure post-stroke cerebellar cognitive affective syndrome: a case report.

Cerebellar pathology commonly shows important motor signs and less evident cognitive dysfunction. The 'cerebellar cognitive affective syndrome' is characterised by impairment on executive function, spatial cognition, language and behaviour. We report the case of a man with acute onset of transitory motor features and severe mental disorders. Cranial CT and brain MRI revealed extended cerebellar lesions. Neuropsychological assessment disclosed deficits of attention, executive function and memory. Auditory event-related potentials showed abnormal P300. These data suggest a pure "cerebellar cognitive affective syndrome"and strengthen the hypothesis of cerebellar cognitive function modulation.

Pudendal nerve somatosensory evoked potentials in probable multiple sclerosis.

Bladder dysfunctions are often observed in patients with multiple sclerosis (MS). In order to evaluate their sensitivity in detecting abnormalities in bladder central control pathways, pudendal nerve somatosensory evoked potentials (pSEPs) were recorded in 16 patients with clinically probable MS: six were affected by retention or urge incontinence, and ten were asymptomatic. Conventional visual, auditory and somatosensory evoked potentials were also recorded, and all of the patients underwent a urodynamic examination. Prolonged latency or the absence of pSEP cortical responses was found in eight of the ten asymptomatic patients, and in all of the symptomatic cases (87.5%). The urodynamic evaluation revealed abnormalities in 12 patients (75%). Our findings seem to indicate an early and frequent involvement of bladder control pathways in MS patients, as well as a high rate of subclinical disorders.

P300 and executive function alterations: possible links in a case of Morgagni-Stewart-Morel syndrome.

To evaluate possible cause-effect relationships between hyperostosis frontalis interna and cognitive dysfunction, we performed a neurophysiological (event-related potentials, ERPs) and neuropsychological study in a case of Morgagni-Stewart-Morel (MSM) syndrome associated with frontal lobe compression. Neuropsychological evaluation evidenced selective impairment of executive function. Visual and auditory oddball ERPs revealed delayed P300 latency and reduced auditory P300 amplitude with multi-peaked morphology. ERP abnormalities and cognitive dysfunction could be due to the frontal bone-cortex conflict documented by neuroradiological investigations.

Longitudinal study of cognitive dysfunction in multiple sclerosis: neuropsychological, neuroradiological, and neurophysiological findings.

OBJECTIVE: (1) To assess cognitive function and cerebral magnetic resonance imaging (MRI) involvement in relapsing-remitting multiple sclerosis; (2) to monitor disease evolution, cognitive dysfunction, and cerebral lesion burden over time (mean 8.5 year follow up period); (3) to study the relation between clinical, neuropsychological, and MRI data. On follow up assessment, visual and auditory oddball event related potentials (ERPs) were recorded as psychophysiological evaluation of cognitive status. Correlations between neuropsychological, MRI, and ERP data were also analysed. METHODS: Neuropsychological study assessed verbal and non-verbal IQ, deterioration index (DI) from WAIS subtests, conceptual reasoning, attention, verbal and visuospatial short-term and long term memory. MRI assessment detected presence of demyelinating lesions by using a semiquantitative method as well as cortical and subcortical atrophy over time. RESULTS: Attention, short-term and long term visuospatial memory were mildly impaired at baseline and remained unaltered longitudinally. At retesting a significant worsening of verbal long term memory (p=0.023), DI presence (p=0.041) and the increase of supratentorial and subtentorial MRI lesions load (p=0.001) emerged. Expanded disability status scale score correlated significantly with total lesion burden at both evaluations (p=0.043 and p=0.024 respectively). Temporal, occipital, and frontal horn lesions as well as cortical atrophy correlated significantly with attention and memory tests at baseline. Follow up assessment revealed significant correlation between cortical atrophy and attention as well as visuospatial short-term memory; spatial long term memory correlated significantly with lesions in body of lateral ventricle and frontal lobe. ERP study showed P300 latency abnormalities in 75% of patients, involving specifically more visual P300 (58.4 % of cases) than auditory wave (41.6 %). Visual P300 latency and amplitude correlated significantly with DI and auditory P300 latency with frontal horn and brain stem lesions. CONCLUSIONS: These findings revealed mild cognitive impairment in MS patients particularly consistent with slowing information processing over time. Increased MRI lesions do not correlate with the clinical course of the disease and cognitive deficit evolution. Thus, cognitive dysfunction could be related to disease peculiarity and not to the time course. Correlations between P300, neuropsychological, and MRI findings provide further information about ERP application to examine cognitive impairment in MS and probably to investigate their neural origin.