The problem of quantifying a simple, often-used clinical ataxia test (tandem-walking) for inclusion in an ataxia test battery was overcome by adopting the method of counting the number of heel-to-toe steps (1 to 10) a person can take without sidestepping with eyes closed and arms folded against chest. Standardization under these rigid conditions was based on testing 287 normal men and 100 normal women. Validation was based on testing 22 individuals having labyrinthine defects of varying severity and origin. This newly quantified test was found to be as valid an indicator of vestibular ataxia as other subtests of a multidimensional quantitative ataxia test battery with which it was compared, and it has the advantages that, it appears to be free of age influences, and nearly all the normal and none of the abnormal individuals obtained a perfect score.

R. B. Stein Department of Physiology, University of Alberta, Edmonton, Canada The impetus for this volume and the conference that gave rise to it was the feeling that studies on motor control had reached a turning point. In recent years, studies on motor units and muscle receptors have become increasingly detailed. Attempts to integrate these studies into quantitative models for the spinal control of posture have appeared and preliminary attempts have been made to include the most direct supraspinal pathways into these models (see for example the chapters by Nashner and Melvill Jones et al. in this volume). Thus, we felt that the time was ripe to summarize these developments in a way which might be useful not only to basic medical scientists, but also to clinicians dealing with disorders of motor control, and to bioengineers attempting to build devices to assist or replace normal control. Over the past few years, computer methods have also made possible increasingly detailed studies of mammalian locomotion, and improved physiological and pharmacological studies have appeared. There seems to be almost universal agreement now that the patterns for locomotion are generated in the spinal cord, and that they can be generated with little, if any, phasic sensory information (see chapters by Grillner and Miller et al. ). This concludes a long controversy on whether chains of reflexes or central circuits generate stepping patterns. The nature of the pattern generators in mammals remains obscure, but invertebrate studies on locomotion have recently made striking advances.

The prevalence of adult cognitive disorders will dramatically rise over the next 25 years due to the aging population. Clinical research on adult cognitive disorders has rapidly evolved, including evidence of new adult cognitive disorders and greater insight into the clinical presentation, mechanism, diagnosis, and treatment of established diseases. The Oxford Handbook of Adult Cognitive Disorders is an up-to-date, scholarly, and comprehensive volume covering most diseases, conditions, and injuries resulting in impairments in cognitive function in adults. Topics covered include normal cognitive and brain aging, the impact of medical disorders and psychiatric illnesses on cognitive function, adult neurodevelopmental disorders, and various neurological conditions. This Handbook also provides a section on unique perspectives and special considerations for clinicians and clinical researchers, covering topics such as cognitive reserve, genetics, diversity, and neuroethics. Readers will be able to draw upon this volume to facilitate clinical practice (including differential diagnosis, treatment recommendations, assessment practices), and to obtain an in-depth review of current research across a wide spectrum of disorders, provided by leaders in their fields. The Oxford Handbook of Adult Cognitive Disorders is a one-of a kind resource appropriate for both clinicians and clinical researchers, from advanced trainees to seasoned professionals.