Humans learn skilled acts in order to effectively interact with their environment. A loss of the ability to perform skilled acts is termed apraxia. Apraxia has been thought to be of theoretical interest, but the ecological implications of apraxia are controversial and have not been fully studied. We examined ten patients with unilateral left hemisphere cerebral infarctions (eight of whom were apraxic) and compared their mealtime eating behavior to a group of neurologically normal, age-matched controls. The stroke patients were less efficient in completing the meal. They made more action errors and were less organized in the sequencing of mealtime activities. Because the patients made more errors while using tools than when performing nontool actions, their deficit could not be accounted for by an elemental motor deficit. A positive relationship was found between mealtime action errors and the severity of apraxia. These findings suggest that limb apraxia may adversely influence activities of daily living. (JINS, 1995, I, 62–66.)

Arbib suggests that language emerged in direct relation to manual gestural communication, that Broca's area participates in producing and imitating gestures, and that emotional facial expressions contributed to gesture-language coevolution. We discuss functional and structural evidence supporting localization of the neuronal modules controlling limb praxis, speech and language, and emotional communication. Current evidence supports completely independent limb praxis and speech/language systems.

The Asymmetrical Brain. Kenneth Hugdahl and Richard J. Davidson (Eds.). 2003. Cambridge, MA: The MIT Press. 796 pp., $90.00.

One of the most fundamental questions in cognitive neuroscience relates to the biological basis of functional hemispheric specialization and the relationship of structure to function. These important and controversial concepts are reviewed in The Asymmetrical Brain. Drs. Hugdahl and Davidson have selected core topics discussed by an impressive group of internationally recognized experts. This text was originally conceived as an update to the 1995 book Brain Asymmetry edited by Hugdahl and Davidson, but this text offers a completely reorganized approach to the topic that is both timely and comprehensive within a narrow focus on specific neural systems and neural syndromes. This book will appeal to students and experts in the broader field of human cognitive neuroscience and should be required reading to anyone with an academic interest in cerebral laterality and human cognition. Indeed, the field has advanced since 1995, and this book will surely become a major impetus to future research advancement in brain laterality.