The Preservation of Consciousness, Automatism, and Movement Control

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Back to table of contents Previous article Next article LetterFull AccessThe Preservation of Consciousness, Automatism, and Movement ControlIraj Derakhshan, Iraj DerakhshanSearch for more papers by this author, Charleston, WVPublished Online:1 Nov 2003AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InEmail SIR: The paper by Devinsky et al.1 contains important laterality indexed information concerning the preservation of consciousness, automatism, and movement control, which deserve to be put in a more cohesive perspective. This in turn could have helped to present the data in a more scientific manner. Specifically, I am referring to the works of Serafetinides2 on the role of the major hemisphere in preservation of consciousness and Serafetinides and Falconer3 on the role of the right (minor) hemisphere in speech automatism. The results of these large numbered and meticulously conducted studies have been confirmed in more recent times,4,5 all indicating that when a seizure occurs with speech arrest, loss of consciousness, and presence of memory of preictal events, the lesion is in the major hemisphere. As these authors recorded epileptiform EEG activity in such patients the process is epileptic by definition, and calling the process convulsive is appropriate in those in which actual convulsion is seen (majority occurring in major hemispheric lesions). To a neurologist, “nonepileptic seizure” is an oxymoron. Of course, “hysterical seizures” do occur, but if the behavior is associated with the rest of the items enumerated above and is seen with a brain lesion in either hemisphere, one must avoid using that confused and confusing terminology.The role of laterality of movement control (alluded to above, and codified in handedness) in maintaining the stream of conscious awareness is becoming clearer. The activating neuronal aggregate devoted to voluntary movements (otherwise called the command center in the major hemisphere) has been recently the subject of an investigation based on a review of the literature and my own data. This ensemble mediates interlimb coordination, guaranteeing the existence of a cohesive self in a brain consisting of two hemispheres. It is only when this asymmetrical interhemispheric relationship is disturbed, such as in surgical callosotomy, Marchiafava-Bignami disease, and traumatic or vascular callosotomy, that the cohesion is lost forever. Cases of ictal automatism, as mentioned above, are instances representing temporary disruption of this cohesion. All references cited indicate that only when the activating moiety (within the major hemisphere) is involved in the epileptogenesis will the person lose consciousness, as the disruptive process is conveyed to the remaining hemisphere via the callosum. Epileptic activity generated within the minor hemisphere is the source of automatisms only, as mentioned above. It cannot be generalized because the callosal traffic for movement is one-way only. This recently described anatomy forms the neural basis for handedness.6 One of its manifestations is the melody lead of the piano players that has been known to musicologists for more than a century. The reason for the delay of all effectors on the left side (in right handers) is the time taken for the command in the major hemisphere to reach the motor cortex on the right via the callosum.References1 Devinsky O, Mesad, S, Alpers K. Nondominant hemisphere lesions and conversion nonepileptic seizures. J Neuropsychiatry Clin Neurosci 2001; 13:367–373Link, Google Scholar2 Serafetinides EA, Hoare RD, Driver MV. Intracarotid sodium amobarbitone and cerebral dominance for speech and consciousness. Brain 1965; 88:107–130.Crossref, Medline, Google Scholar3 Serafetinides, EA, Falconer MA. Speech disturbances in temporal lobe lesions: A study in hundred epileptic patients submitted to anterior temporal lobectomy. Brain 1963; 86:333–346Crossref, Medline, Google Scholar4 Ebner A, Dinner DS, Noachtar S, Luders H. Automatism with preserved responsiveness: A lateralizing sign in psychomotor seizures. Neurology 1995; 45:61–64Crossref, Medline, Google Scholar5 Karlov VA, Selitskii GV, Sviderskaya NE: The trigger role of the left cerebral hemisphere in the generalization of epileptic activity. Neurosci Behav Physiol. 1993; 23:280–289Google Scholar6 Derakhshan I. In defense of the sinistrals: Anatomy of handedness and the safety of prenatal ultrasound. Obstet Gynecol 2003; 21:209–212Google Scholar FiguresReferencesCited byDetailsCited ByElectroencephalogram and Laterality of Movement Control: A Clinical Analysis2 July 2016 | Journal of Child Neurology, Vol. 18, No. 12 Volume 15Issue 4 November 2003Pages 456-456 Metrics PDF download History Published online 1 November 2003 Published in print 1 November 2003