Cluster analysis of behavioural and event-related potentials during a contingent negative variation paradigm in remitting-relapsing and benign forms of multiple sclerosis.

Background: Event-related potentials (ERPs) may be used as a highly sensitive way of detecting subtle degrees of cognitive dysfunction. On the other hand, impairment of cognitive skills is increasingly recognised as a hallmark of patients suffering from multiple sclerosis (MS). We sought to determine the psychophysiological pattern of information processing among MS patients with the relapsing-remitting form of the disease and low physical disability considered as two subtypes: 'typical relapsing-remitting' (RRMS) and 'benign MS' (BMS).

Quantitative electroencephalography reveals different physiological profiles between benign and remitting-relapsing multiple sclerosis patients.

Background: A possible method of finding physiological markers of multiple sclerosis (MS) is the application of EEG quantification (QEEG) of brain activity when the subject is stressed by the demands of a cognitive task. In particular, modulations of the spectral content that take place in the EEG of patients with multiple sclerosis remitting-relapsing (RRMS) and benign multiple sclerosis (BMS) during a visuo-spatial task need to be observed.

Methods: The sample consisted of 19 patients with RRMS, 10 with BMS, and 21 control subjects.

Differential cognitive impairment for diverse forms of multiple sclerosis.

Background: Cognitive impairment is a common feature in multiple sclerosis (MS) patients and occurs in 60% of all cases. Unfortunately, neurological examination does not always agree with the neuropsychological evaluation in determining the cognitive profile of the patient. On the other hand, psychophysiological techniques such as event-related potentials (ERPs) can help in evaluating cognitive impairment in different pathologies.

Reduction of EEG power during expectancy periods in humans.

The contingent negative variation (CNV), and the associated event-related desynchronization (ERD) on motor areas and sensory areas, and increase of alpha in the ipsilateral to the cued stimulus side, are different brain signals that reflect motor, sensory, and cognitive activations related to the expectancy of the next stimulus. However, the possibility of an overall change in EEG oscillatory activity during expectancy periods has not been directly addressed. The present report tests whether the background oscillatory activity is modulated by a warning signal.

Task-specific sensory and motor preparatory activation revealed by contingent magnetic variation.

The present report studied the magnetic counterpart (CMV) of the auditory contingent negative variation (CNV). The ear where the target auditory stimulus would be presented was cued with a visual central arrow at a validity of 84%. The subject's behavioral response and the magnetoencephalographic (MEG) and electroencephalographic (EEG) signals were recorded.