Effects of Paroxysmal Spike‐Wave on Continuous Visual‐Motor Performance

Abstract

a few had been referred to the Department of Neurology of the University of Virginia. All patients were having clinical absence attacks with generalized spike-wave activity during routine electroencephalography. Most of the patients had several electroencephalograms and none revealed focal discharge. They were 7-19 years old, and none was retarded. One child, for whom no IQ score was available, was thought to have borderline subnormal intelligence but he had no difficulty with the pursuit-rotor task.A photoelectric rotary pursuit apparatus**, requiring the subject to follow with a pointer an illuminated target moving in a circular track, was used in all experiments. Output from the photoelectric cell was connected to one channel of a standard EEG apparatus to give a marking signal whenever the patient's pointer was off-target. Each testing session was video-recorded with a close-up of the subject's face, three channels from the electroencephalograph (one for the marking of signal from the photoelectric cell), and a full-body view of the patient, who was standing to operate the pursuit-rotor ( Fig. 1).To familiarize each patient with the apparatus and to reduce fluctuations in performance caused by learning, five 3-min practice periods were carried out prior to recording. Each patient was then allowed a recess. The electrodes were then applied and the cameras aimed. Use of the pursuit-rotor was divided into 7 periods of 3 min of continuous performance alternating with 2 min of rest. The patients were encouraged to inform the examiner if they became fatigued, and the periods of performance were shortened and the periods for rest were lengthened. The velocity of the target was set during the last practice period so that about one error occurred every 10 sec. However, several subjects were quite poor performers, and this level of performance was not always attained. Methods of analysis were used to account for this variation, since each patient's performance during spike-wave activity was compared to his performance when the EEG record was normal.If a clinically observable seizure occurred during testing, nothing was said to the patient, and he was allowed to resume his performance spontaneously without clues from the examiner.All EEG abnormalities were delineated and checked against the video-taped record to eliminate abnormalities due to artifact and to oderve any clinical accompaniment. Three types of analysis were used. First, the proportion of time in errors during spikewave was compared to the proportion of time in errors when the EEG was normal. Errors in performance during the EEG paroxysms (error B in Fig. 2) were counted, A pilot study consisting of 4 clinical centers (New England

Anticonvulsant drugs and mental symptoms: a review

“…This study, however, must be interpreted with caution for several reasons: (1) 15 of their 25 patients were mentally retarded; (2) the patients were receiving other drugs at the time of the trial; (3) they did not include a control group for comparison. The importance of proper controls in such a study as this is paramount, especially as it has been shown that EEG spike/wave activity of petit mal epilepsy may be correlated with impaired visual-motor performance (Goode et al, 1970). An important feature that the study again emphasizes, however, is the necessity to explore as many individual components of intellectual functioning as possible.…”

Distúrbio cognitivo transitório associado a atividade epileptiforme generalizada ou difusa durante o eletrencefalograma

“…Por vezes, essas descargas apareceram entre uma resposta e o estímulo seguinte, o u seja, em momento inadequado para a análise. Provavelmente houve inibição das descargas nas atividades cognitivas, fato também relatado em outras séries de pacientes com AE generalizada 21,23 . É possível que a utilização, em cada paciente, de testes mais variados e de diferentes níveis de dificuldade, pudesse identificar os que ocasionassem menor redução de AE 2 5 .…”

“…Recentemente tem sido mostrada a redução da AE com algumas drogas antiepilépticas 1 7 , 1 8 , o que tem trazido benefícios cognitivos aos pacientes, em certas condições clínicas 18,19 . As pesquisas sobre DCT são ainda pouco num e rosas e apresentam limitações em vários aspectos, como o número de indivíduos, distinção entre DCT e crise evidente e o tipo de casuística estudada 6,20,21 , O objetivo desta pesquisa é estudar a ocorr ê ncia de DCT associado a AE generalizada ou difusa com a aplicação de vários testes cognitivos.…”

Consciousness: A Neurological Perspective

“…It has been suggested that this phenomenon is due the spreading of pathological electrophysiological discharges to the frontal networks involved in attentional control [33,75]. Thus individuals undergoing limbic status epilepticus may be somewhat aware of their environment, but are focusing their attention on the vivid experiential phenomena induced by the electrical stimulation of the temporal lobe [31].…”