Neuropsychology

Neuropsychology Prepared by: CiciliaEviGradDiplSc., M. Psi

The Development • “Psychology has a long past but a short history” (Ebbinghaus) • The same thing can be said for Neuropsychology

Historical Roots - Egyptians • Ancient Egyptians believed that heart and diaphragm were the seats of mental life (Feinberg & Farah, 1997) • Heart, liver, spleen and other organs were carefully removed from dead body and stored in separate jars  while the brain was simply discarded  considered unimportant (Rains, 2002)

The first recorded evidence on brain – behavior relationship: The Edwin Smith Surgical Papyrus (2000 B.C.)  was misleading • The impairments were ipsilateral to the lesion (same side) rather than contralateral (opposite side) • Egyptian observers didn’t take theoretical leap despite their findings

Historical Roots – Greeks • Alcmaeon of Croton (500 BC)  the first neurologist or neuropsychologist  proposed that the brain is ‘the seat of the soul’ • Plato (400 BC)  similar proposal: the head is part of the body closest to heaven and therefore most likely to contain the most divine organ

On the other hand  pitfalls of rationalism • Empedocles (500BC)  heart was ‘the seat of the soul’ • Aristotle (400BC) agreed: • Brain with its elaborate network of blood vessels and its position near the surface of the body  served to cool the blood • Heart, being an active and central structure was more suitable as the organ of feeling and thinking

Hippocrates (400 BC) had his brain hypothesis  brain was responsible for the intellect, senses, knowledge, emotions and even mental illness (Adams, 1932) • In ‘On The Sacred Disease’  epilepsy is a medical condition, not demonic possession • Found contralateral relationship • Head injury on the left side  seizure on the right side • Head injury on the left side  speech impairments

Historical Roots • Romans accepted the brain hypothesis • Localization of function  where in the brain various psychological functions (perception, memory and thinking) take place? • Galen of Pergamus  cerebral ventricles, fluid-filled cavities deep within the brain, were the structures in which thinking and other psychological processes were localized

Nemesius (4th century)  ventricular hypothesis  assigning different psychological processes to locations within different ventricles • Cellulaphantastica  seat of perception • Cellulalogistica  seat of reasoning and cognition • Cellulamemoralis  seat of memory • This theory was lack of empirical support … until 19th century

Mind – Body Problem • Monism  hold to one belief, either physical (materialism) or spiritual (idealism) • Dualism  Rene Descartes  there is brain and there is mind, independent of each other but they interact. • Pineal gland  organ that mediate the interaction • No localization of function  because the mind was not localized, wasn’t in space at all • Holism  whole brain mediates all functioning

Modern Neuropsychology • Franz Joseph Gall and Johann Casper Spurzheim phrenology  relating specific brain regions to particular faculties or functions  no precise definition or empirical basis • Jean BaptisteBouillaud  left-hemisphere specialize for motor dexterity, underlying right-handedness, also specialized movements involved in speech

Modern Neuropsychology (2) • Paul Broca • A patient, Leborgne called ‘Tan’  epileptic, right hemiplegia and loss of speech for over 20 years  understood language, not demented, responded accurately to questions asked through gestures, such as his age  after his dead, found a lesion on his left hemisphere • In 1865  Broca concluded that left hemisphere is dominant for language • Marc Dax’s view

Definition • Meier (1974)  Neuropsychology is the scientific study of brain – behavior relationships • Subfields: clinical neuropsychology, experimental neuropsychology, behavioral neurology, and behavioral neuropsychology

Clinical Neuropsychology • The application of our understanding of human brain – behavior relationships to clinical problems (Horton, Wedding & Phay, 1981) • Clinical Neuropsychologist is a professional psychologist with diagnostic skills and psychometric expertise applicable to behavioral dysfunction associated with CNS dysfunction • Halstead – Reitan Neuropsychology Battery and Luria – Nebraska Neuropsychology Battery

Experimental Neuropsychology • Elucidation of basic brain – behavior relationship (Horton, Wedding & Phay, 1981) • Focus on theoretical questions rather than practical ones  nonhuman subjects • Degree of generality depends on the species and area of psychology under study

Behavioral Neurology • Concerned with clinical application of scientific knowledge  using qualitative, intuitive approach • Contrast with clinical neuropsychology which used psychometric and quantitative approach • Traditional medical case study approach  assumes the practitioner has considerable clinical expertise and thorough understanding of neural structure and function

Behavioral Neuropsychology • Horton (1979)  the application of behavior therapy techniques to problems of organically impaired individuals while using a neuropsychological assessment and intervention perspective • Emphasis on the problems of management, retraining, and rehabilitation

Psychometric Approach to Neuropsychology • Case study approach  revealed in-depth study of single individual case  but we need more … • Group Studies  started at 40-50s  allowed the formation of control groups to reveal the nature of impairments associated with a particular lesion  result: quantitative definitions of impairments and sensitivity of specific tests to the presence of impairments

Statistical analyses  used to quantify the probability that a group with a particular lesion is performing at a lower level than a control group on a particular task  help us to understand cerebral organization of psychological processes • Also provide a basis for making inferences regarding the presence of cognitive impairments and associated cerebral abnormality in that individual (Reitan & Davidson, 1974)  provide a set of procedures in diagnosis and rehabilitation (Lezak, 1995)

Case Study? • Still effective in very rare disorders (agnosia or aphasia)  provide a vivid and detailed description of the impairment that is often lost in the analysis of group data • Individual differences and avoid overgeneralized appraisal of the effects of particular lesions • Group study defined on the basis of lesion sites  may comprise subjects with widely varying lesion sites  erroneous interpretation

Summary • Erroneous idea of mind-body relationship can remain widely accepted for long periods • Establishment of localization of function within cerebral cortex and the specialization of left hemisphere for language  mid 19th century • An awareness of historical antecedents of current controversies helps place them in perspective and provides a framework for possible resolutions

Neuropsychology