The Evoked Response as a Measure of Cerebral Dysfunction

Dustman, Robert E.; Snyder, Edward W.; Callner, D. A.; Beck, Edward C.

doi:10.1007/978-1-4684-3462-0_14

Cited by 25 publications

(13 citation statements)

References 60 publications

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“…Moreover, altered SNAPs were most often observed in patients exhibiting sensory signs or symptoms, or were sometimes related to associated medical conditions (polyneuropathy, median or ulnar nerve entrapment neuropathies) 12 20 25 27–30. In line with this, the various components of cortical SEPs are not altered unequally, whether in amplitude and/or latency, and given the multiple origins of the SEP components,31 some authors have suggested that abnormal SEPs in ALS are not due to sensory defects but to abnormal cortico-cortical interactions 24 32…”

Section: Introductionmentioning

confidence: 86%

Electrophysiological and spinal imaging evidences for sensory dysfunction in amyotrophic lateral sclerosis

et al. 2015

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ObjectivesThe prevalence of sensory impairment at an early stage of amyotrophic lateral sclerosis (ALS) is still debated. The study aim was to investigate the anatomofunctional properties of sensory pathways in patients with ALS, combining spinal diffusion tensor imaging (DTI) and somatosensory evoked potentials (SEPs).DesignCase–control study.SettingsALS referral centre and laboratory of biomedical imaging (Paris, France).ParticipantsWell-characterised group of 21 patients with ALS with moderate disability (mean amyotrophic lateral sclerosis Functional Rating Scale (ALSFRS) score 39.3±1.0) and no clinical sensory signs and control group of 21 gender and age-matched healthy subjects.Outcome measuresFractional anisotropy and diffusivity of the dorsal columns at C5-T1 levels (DTI metrics) and SEPs after median and ulnar nerve stimulations (latency and amplitude of N9 and N20 components).ResultsAbnormal DTI metrics indicated anatomical damages of ascending sensory fibres in ∼60% of patients (p<0.05). Raw SEPs (μV) were smaller in ∼40% of patients but the difference with healthy subjects was not significant (p>0.16). Their normalisation to prestimulus activity strengthened the difference between groups (p<0.05) and allowed identification of ∼60% of patients with abnormal values. According to N9 latency, the peripheral conduction time was normal in patients (p>0.32) but based on N20 latency, the central conduction time (between spinal cord and parietal cortex) was found to be slower (p<0.05). Significant correlation was found between DTI metrics and N9 amplitude (p<0.05). Altered SEPs were also correlated with the disease duration (p<0.05). Taken together, spinal imaging and electrophysiology helped to identify ∼85% of patients with subclinical sensory defect while separated methods revealed abnormal values in ∼60%.ConclusionsSensory impairments have been underestimated at early stages of ALS. These results show for the first time the interest to combine electrophysiology and imaging to assess non-motor system involvement in ALS.Trial registration numberIDRCB2012-A00016-37.

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Section: Introductionmentioning

confidence: 86%

Electrophysiological and spinal imaging evidences for sensory dysfunction in amyotrophic lateral sclerosis

et al. 2015

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“…Previous information strongly suggests that this effect represents an amplitude depression of components within the detoxified group rather than enhanced amplitudes in intoxicated persons. Several investigators have reported that abstinent alcoholics display lower voltage amplitudes of the N1 component (Dustman et al 1979;Begleiter 1979, 1980;Begleiter et al 1980), the P2 component (Porjesz and Begleiter 1981;Posthuma and Visser 1982), and the N2-P3 deflection (Porjesz and Begleiter 1982). While the exact relation of the N2P3 deflection to information processing is unclear, it is likely to reflect encoding of information from sensory store to working memory.…”

Section: Discussionmentioning

confidence: 99%

Event-related brain potentials in intoxicated and detoxified alcoholics during visuospatial learning

Schandler

Cohen

McArthur³

1988

Psychopharmacology

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Event-related potentials and visuospatial learning performance were examined to understand the effects of chronic alcohol use on complex information processing. A total of 18 alcoholic male in-patients in an alcohol treatment program served as participants. Nine persons were seen at time of admission to the program while intoxicated (mean BAC = 18.0 mg/dl). The second group of nine persons was seen detoxified after 4 weeks in the treatment program. Learning consisted of a paired-associate paradigm requiring participants to learn the distinct spatial positions of six, randomly presented "nonsense" shapes. The visuospatial learning performance of the intoxicated alcoholics was superior to that of the detoxified alcoholics. Evaluation of event-related potentials during the visuospatial learning task indicated that while both groups displayed greater right hemisphere amplitudes of P3, P2, N1, and N2-P3 components, the amplitudes of the latter three components were significantly greater in the intoxicated alcoholics. The overall results suggest that compared to the intoxicated alcoholic, the detoxified alcoholic may suffer a disruption in attentional mechanisms related to visuospatial information processing, providing support for a theory that alcohol ingestion serves to balance information processing in the chronic alcoholic.

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“…The recordings were carried out with silver-silver chloride electrodes placed at Erb's point (EP), CVII, and P3/P4 postcentral cortical zones 7 cm lateral to Cz and 3 cm behind the Cz-ear line; these active derivations, contralateral to the stimulated nerve, were referred to the Fz electrode (often the EP lead was referred to a noncephalic (NC) site). SEPs were also obtained with central (C3/C4) and frontal (F3/F4) electrodes according to the [10][11][12][13][14][15][16][17][18][19][20] International System. For all scalp leads, includ-ing the postrolandic ones, the ipsilateral earlobe was chosen as the reference instead of Fz in order to record the cortical potentials.…”

Section: Methodsmentioning

confidence: 99%

Far‐field and cortical somatosensory evoked potentials in motor neuron disease

et al. 1990

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We examined median somatosensory evoked potentials (SEPs) in 26 patients with sporadic motor neuron disease (MND). SEPs were recorded with multiple scalp derivations, using both the midfront and the earlobe as references for each subject. Central conduction time (CCT) was abnormal in three patients, but only when using the midfront reference. Moreover, an exclusive alteration of the early prerolandic potentials (absent or delayed P20 and/or P22) was noted using the earlobe reference in amyotrophic lateral sclerosis and in progressive bulbar palsy (54% and 50% of patients, respectively) but not in progressive muscular atrophy. These findings correlated with clinical evidence of upper motor neuron signs and with the severity of the disease. In agreement with recent views regarding the sources of the early anterior cortical responses, neuronal loss in the motor cortex may be considered as affecting the generator sites of these potentials.

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The Evoked Response as a Measure of Cerebral Dysfunction

Cited by 25 publications

References 60 publications

Electrophysiological and spinal imaging evidences for sensory dysfunction in amyotrophic lateral sclerosis

Electrophysiological and spinal imaging evidences for sensory dysfunction in amyotrophic lateral sclerosis

Event-related brain potentials in intoxicated and detoxified alcoholics during visuospatial learning

Far‐field and cortical somatosensory evoked potentials in motor neuron disease

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