Imitation of gestures by disconnected hemispheres

PU's corpus callosum was severed as a sequel of bleeding from an arteriovenous malformation. The lesion affects the truncus and the splenium and caused somatosensory and visual disconnection of the hemispheres. On clinical testing PU's left hand was apraxic for pantomime of object use but not for imitation. By contrast, when stimuli for imitation of meaningless hand and finger postures were presented tachistocopically to either the left or the right visual field, both hemispheres turned out to be apraxic in different ways. Imitation of hand postures was perfect for right-handed imitation of stimuli presented to the left hemisphere but defective in all other conditions. Imitation of finger postures was below the normal range in all conditions initially, but improved to normality for right-hand imitation of stimuli presented to the left hemisphere after repeated testing. After successful imitation of gestures presented to the left hemisphere PU commented that he imitated without really seeing the stimulus by "formulating the unseen", whereas after presentation to the right hemisphere he felt that he saw the stimulus but could not imitate. We propose that imitation of meaningless gestures affords a coding of gestures with reference to knowledge about body parts which can be applied only by the left hemisphere. Imitation of finger postures puts additional demands on fine grained visuospatial discrimination which necessitates a contribution by the right hemisphere.

[1]  K. Heilman,et al.  A Cognitive Neuropsychological Model of Limb Praxis , 1991 .

[2]  A. Sirigu,et al.  Multiple representations contribute to body knowledge processing. Evidence from a case of autotopagnosia. , 1991, Brain : a journal of neurology.

[3]  K. Haaland,et al.  The different types of limb apraxia errors made by patients with left vs. right hemisphere damage , 1984, Brain and Cognition.

[4]  G. Goldenberg.  Defective imitation of gestures in patients with damage in the left or right hemispheres. , 1996, Journal of neurology, neurosurgery, and psychiatry.

[5]  H. Liepmann.  Drei Aufsätze aus dem Apraxiegebiet , 1908 .

[6]  L. Deangelis,et al.  Multiple paragangliomas in neurofibromatosis: a new neuroendocrine neoplasia. , 1987, Neurology.

[7]  H. Liepmann,et al.  Fall von linksseitiger Agraphie und Apraxie bei rechtseitiger Lahmung , 1907 .

[8]  Wolfgang Prinz,et al.  Why don't we perceive our brain states? , 1992 .

[9]  G. Goldenberg,et al.  Tool use and mechanical problem solving in apraxia , 1998, Neuropsychologia.

[10]  Georg Goldenberg,et al.  Imitating gestures and manipulating a mannikin—The representation of the human body in ideomotor apraxia , 1995, Neuropsychologia.

[11]  R. Hashimoto,et al.  Diagonistic dyspraxia. Clinical characteristics, responsible lesion and possible underlying mechanism. , 1996, Brain : a journal of neurology.

[12]  Roger W. Sperry,et al.  Some long-term motor effects of cerebral commissurotomy in man , 1977, Neuropsychologia.

[13]  Y. Tanaka,et al.  Diagonistic dyspraxia , 1990, Neurology.

[14]  P. Marangolo,et al.  Let not thy left hand know what thy right hand knoweth. The case of a patient with an infarct involving the callosal pathways. , 1998, Brain : a journal of neurology.

[15]  R. Byrne,et al.  Priming primates: Human and otherwise , 1998, Behavioral and Brain Sciences.

[16]  D. Kimura,et al.  Motor functions of the left hemisphere. , 1974, Brain : a journal of neurology.

[17]  E. Renzi,et al.  Imitating gestures. A quantitative approach to ideomotor apraxia. , 1980, Archives of neurology.

[18]  J. G. Snodgrass,et al.  A standardized set of 260 pictures: norms for name agreement, image agreement, familiarity, and visual complexity. , 1980, Journal of experimental psychology. Human learning and memory.

[19]  Dr. phil. et med. H. Liepmann.  Das Krankheitsbild der Apraxie (“motorische Asymbolie”) auf Grund eines Falles von einseitiger Apraxie (Schluss.) , 1900 .

[20]  G. Goldenberg.  Matching and imitation of hand and finger posturesin patients with damage in the left or right hemispheres , 1999, Neuropsychologia.

[21]  M. Giroud,et al.  Clinical and topographical range of callosal infarction: a clinical and radiological correlation study. , 1995, Journal of neurology, neurosurgery, and psychiatry.

[22]  H. Lausberg,et al.  Callosal disconnection syndrome in a left-handed patient due to infarction of the total length of the corpus callosum , 1999, Neuropsychologia.

[23]  M. Gazzaniga,et al.  Collaboration between the hemispheres of a callosotomy patient. Emerging right hemisphere speech and the left hemisphere interpreter. , 1996, Brain : a journal of neurology.

[24]  Yasufumi Tanaka,et al.  Right Hand Agraphia and Left Hand Apraxia Following Callosal Damage in a Right-Hander , 1990, Cortex.

[25]  M. Gazzaniga,et al.  Cortical mechanisms involved in praxis , 1982, Neurology.

[26]  G. Goldenberg,et al.  The meaning of meaningless gestures: A study of visuo-imitative apraxia , 1997, Neuropsychologia.

[27]  M S Gazzaniga,et al.  Dyspraxia following division of the cerebral commissures. , 1967, Archives of neurology.

[28]  J Hermsdörfer,et al.  Kinematic analysis of movement imitation in apraxia. , 1996, Brain : a journal of neurology.

[29]  S. Kazui,et al.  Callosal apraxia without agraphia , 1993, Annals of neurology.

[30]  D. Benson,et al.  The Dual brain : hemispheric specialization in humans , 1985 .

[31]  M. Mehler.  Visuo-Imitative Apraxia , 1987 .

[32]  A. Meltzoff,et al.  Explaining Facial Imitation: A Theoretical Model. , 1997, Early development & parenting.

[33]  N. Geschwind,et al.  A Human Cerebral Deconnection Syndrome , 1974 .

[34]  G. Goldenberg,et al.  Apraxia of the Left Limbs in a Case of Callosal Disconnection: The Contribution of Medial Frontal Lobe Damage , 1985, Cortex.