• Composed of neurons
  • CNS (brain and spinal cord)
  • PNS (neurons that convey messages to and from the rest of the body)
  • Cerebrum divided in 2 hemis
  • Each of the two cerebral semis receives sensory information from the opposite side of the body and also controls motor responses on the opposite side of the body—> contralateral control
  • It is due to the brain’s contralateral control of the body that an injury to the right side of the brain may result in sensory or motor defects on the left side of the body
  • Meeting ground of two hemis is corpus callosum
  • Typically left semi is dominant —> because the left hemi is dominant that most people are right handed
  • dominant hemi leads in such activities as reading, writing, arithmetic and speech
  • non dominant hemi leads in tasks involving spatial and textural recognition, as well as art and music appreciation

Neurological damage and the concept of organicity

  • Beyond the usual tools of psychological assessment (tests, case studies etc.), investigators employ high-technology imaging equipment, experimentation involving the electrical or chemical stimulation of various human and animal brain sites, experimentation involving surgical alteration of the brains of animal subjects, lab testing and field observation of head trauma victims, and autopsies of normal and abnormal human and animal subjects.
  • Neurological damage: may take form of lesion in the brain or any other site within the CNS or PNS
  • Lesion: a pathological alteration of tissue, such as that which could result from an injury or infection.
  • Lesions may be physical or chemical in nature, and they are characterised as focal (relatively circumscribed to one site) or diffuse (scattered at various sites).
  • Because different sites of the brain control various functions, focal and diffuse lesions at different sites will manifest themselves in varying behavioural deficits
  • A focal lesion in one area of the brain may affect many different kinds of behaviours, even variables such as mood, personality, and tolerance to fatigue
  • It is possible for a diffuse lesion to affect one or more areas of functioning so severely that is masquerades as a focal lesion.
  • Therefore, neuropsychologists sometimes work backwards as they try to determine from outward behaviour where neurological lesions, if any, may be
  • Neurological assessment may also play a critical role in determining the extent of behavioural impairment that has occurred or can be expected to occur as the result of a neurological disorder or injury
  • neurological damage: cover damage to CNS and PNS
  • brain damage: general reference to any physical or functional impairment n the CNS that results in sensory, motor, cognitive, emotional or related deficit
  • Organicity: factors differentiating organically impaired from normal individuals include loss of abstraction ability, deficits in reasoning ability, and inflexibility in problem-solving tasks
  • Brain damage refers to the fact of an anatomical distribution, whereas organicity represents one of the varieties of functional consequences which may attend such destruction
  • View that organicity and brain damage are non unitary is supported by a number of observations
  • Persons who have identical lesions in the brain may exhibit markedly different symptoms
  • Many interacting factors may make one organically impaired individual appear clinically quite dissimilar from another
  • Similarity in symptoms may exist in people with different types of lesions
  • Many conditions that are not due to brain damage can produce symptoms that mimic those produced by brain damage e.g. psychotic, depression, or simply fatigued
  • Factors other than brain damage influence the responses of brain damaged patients
  • Persons who are brain damaged are sometimes able to compensate for their deficits to such an extent that some functions are actually taken over by other, more intact parts of the brain

THE NEUROPSYCHOLOGICAL EVALUATION

When a neuropsychological evaluation is indicated

  • If non-specialists e.g. school psychologist identify a problem that they believe is neuropsychological in nature, whether through their own examination or through test or case history data, a referral to a specialist ensues.
  • In some cases, a patient is referred t a psychologist (who is not a neuropsychologist) for serving for suspected neuropsycholgoical problems —> battery of tests given —> intelligence test, personality test ,and a perceptual motor/memory test (at minimum)
  • If suspicious neurological signs are discovered in the course of the evaluation, the patient will be referred for further and more detailed evaluation
  • Signs of neurological deficit: troubling episodes (e.g. hand tremor or other involuntary movement) that only seem to occur home, at work or some other venue
  • Presence of signs or symptoms of neurological impairment, the occurrence of various events e.g. concussion or the existence of some known pathology may prompt a referral for evaluation by a specialist
  • Signs signalling that a more thorough neuropsychological or neurolgoist workup by a specialist is advisable are characterised as being “hard’ or “soft”
    • Hard sign: indicator of definite neurological deficit
    • g. abnormal reflex
    • Soft sign: indicator that is merely suggestive of neurological deficit
    • g. an apparent inability to accurately copy a stimulus figure when attempting to draw it, or scores on a test that has verbal and nonverbal components where a significant discrepancy exists between the testtaker’s verbal and non verbal performance
  • Patient may be referred for an in-depth neuropsychological evaluation, for complaints such as headaches and memory loss – after a neurologist has done an evaluation and found no medical basis for the complaint
  • Neuropsych may be called upon to more precisely assess the degree of a neurological patient’s impairment in functioning
  • A patient placed on a particular treatment regimen by a neurologist may be referred to a neuropsychologist to monitor subtle cognitive changes that result as a consequence of that treatment.

General elements of a Neuropsychological Evaluation

  • Objective of the typical neuropsychological evaluation: to draw inferences about the structural and functional characteristics of a person’s brain by evaluating an individual’s behaviour in defined stimulus-response situations
  • Examination typically begins with a thorough examination of available, relevant records
  • Case history data e.g. medical records, educational records, family reports, employer reports, prior neuropsych evaluation records, are all useful to the neuropsych planning the examination
  • A way must be found to administer the appropriate tests so that meaningful results can be obtained as neuropsychs assess persons exhibiting a wide range of physical and psychological disabilities
  • Common to all thorough neuropsychological examinations are a history taking, a mental status examination, and the administration of tests and procedures designed to reveal problems of neuropsychological functioning.
  • Decisions concerning when to test —> e.g. it would be atypical for a neuropsychologist to psychologically test a stroke victim immediately after the stroke has occurred. Because some recovery of function could be expected to spontaneously occur in the weeks and months following the stroke, testing the patient immediately after the stroke would therefore yield an erroneous picture of the extent of the damage.
  • neuropsychologists must also have a knowledge of the possible effects of various prescription medications taken by their assessees because such medication can actually cause certain neurobehavioral deficits.
  • test, the case study, and the interview

History taking, the case history & case studies