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Chapter 4

PS280 Chapter 4 - Psychological Assessment and Research Methods.docx

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Department
Psychology
Course
PS280
Professor
Camie Condon
Semester
Summer

Description
C HAPTER 4: P SYCHOLOGICAL A SSESSMENT & R ESEARCH M ETHODS A SSESSMENT  Psychological assessment – a systematic gathering and evaluation of info pertaining to an individual with suspected abnormal behaviour  Can be carried out with a wide variety of techniques to appraise social, psychological, and or/biological factors  Good diagnosis hinges on the development of accurate assessment tools  Psychological assessment is not a single score but a series of scores placed in order to provide a comprehensive understanding of that individual within the context of the: o history, o referral info, o behaviour observations, o and life of an individual  A test is only a sample of behaviour – a tool used in the process of assessment  Example: blood sample o The medical assessment takes the blood work info from the lab o Lab results are then integrates it with other info (e.g. symptoms, age, etc.) o These series of info are then used to understand the individual’s presenting complaints and problems  Assessments may also have other specific purposes: o An IQ test may be used to guide school placement o A neuropsychological tests to assess the natural progression of a disorder o A symptom checklist to facilitate case formulation  A good assessment tool depends on two things: o An accurate ability to measure some aspect of the person being assessed o Knowledge of how people in general fare on such a measure, for the purpose of comparison Assessment Tools: Striving for the Whole Picture  In order to achieve an accurate assessment, we piece together the patient's own self-assessment and past experiences with their emotional, cognitive and physiological states found through psychological methods of assessment  Sometimes patients cannot report on their own internal states, even when they can accurately describe their observable behaviour Reliability and Validity  Test-retest reliability – when a test yields the same results when it is given more than once to the same person o Can be evaluated by correlating a person’s score on a given test with the same person’s score on the same test taken at a later time o The higher the relationship between the two scores, the greater the reliability o The person may improve on a test the second time around because of practice with the procedures or familiarity with the questions  behavioural scientists often attempt to ascertain a test’s alternate-form reliability – give two forms of the same test that ask essentially the same questions to test a specific construct with slightly different wording o a high correlation between scores on tests = high alternate-form reliability that eliminates practice effects  internal consistency – reliability within a test o the extent of which the different parts of the same test yield the same result o methods of measuring internal consistency:  split-half reliability – compares responses on odd-numbered test items with responses on even-numbered test items  High correlation = high split-half reliability = higher internal consistency of the test  coefficient alpha – calculated by averaging the intercorrelations of all items on a given test  high correlation = high coefficient alpha = higher internal consistency of the test o a reliable measure may be of little value if it’s not valid  other validity measurements related to psychological testing: o concurrent validity o predictive validity o face validity – the user of a test believes that the items on that test resemble the characteristics associated with the concept being tested for  Example: a test for assertiveness, “How do you react when overcharged at a store?”  Such behaviours relate to the general concept of assertiveness, so test would have face validity o content validity – a test’s content include a representative sample of behaviours thought to be related to the construct (i.e. the concept or entity) that the test is designed to measure  Example: construct of depression includes features like lack of energy, sadness, etc.  A test that focused only on one feature without considering other features would not have good content validity o criterion validity – arises because some qualities are easier to recognize than to define completely  Example: measuring artistic ability between a large group of well-known, highly regarded artists and to a large group of control group, not defined as artists.  If results show that artists’ tests are higher than the non-artists scores, the test has good criterion validity  You start with an assumption that the artists are artistic; it is the instrument that is being tested not the people involved o construct validity – the importance of a test within a specific theoretical framework and can only be understood in the context of that framework  this is useful when the construct to be measured is rather abstract  Example: self-esteem is considered important for success; to evaluate how well a measure assesses self- esteem, we would look to a theory for a prediction and see whether the measure correlates well with that prediction  One would judge the construct validity of the self-esteem measure in terms of how closely it was related to the backgrounds of the test subjects (i.e. two groups of teenagers: supportive families, and neglected/abused families) Clinical vs. Actuarial Prediction  Clinical approach – there is no substitute for the clinician’s experience o they prefer to draw on all available data in their own manner o they are guided by intuition honed with professional experience rather than formal rules  Actuarial approach – more objective standard is needed; something more unbiased and scientifically validated o They rely exclusively on statistical procedures, empirical methods, and formal rules in evaluating data  It has been suggested that the actuarial approach tends to be more efficient in terms of making predictions in a variety of situations (e.g. relapse, dangerousness, improvement in therapy, etc.) especially when many predications must be made and the base of data is large  Many clinicians, however, still rely on the clinical method  Statistical rules do outperform clinical hunches, but there are two basic problems with them: o 1) Many of the equations and algorithms found in the literature don’t generalize to practice settings o 2) There are no prediction rules for the bulk of our decisions B IOLOGICAL A SSESSMENT  It is important to be aware of any medical conditions that may be causing or contributing such abnormal behaviour  It is important that a general physical examination be conducted as part of an assessment for psychological disorders Brain Imaging Techniques One of the oldest and most well-established techniques is the electroencephalogram (EEG) – uses electrodes placed on various parts of the scalp to measure the brain’s electrical activity; the impulses are then amplified and recorded by equipment specialized for the task. Some patients may be asked to take visual or auditory tasks to see how various brain parts respond. Many seizure disorders, brain lesions, and tumours can be detected through EEG examinations. 1. Computed tomography (CT)  Computerize axial tomography – a narrow band of X-rays is projected through the head and onto scintillation crystals, which are more sensitive than X-ray film. (shows brain’s anatomy)  the E-ray source and detector then rotate very slightly and project another image  the source rotates 180 degrees, producing a number of images at predetermined angles  the pictures are then combined to produce a detailed tomography or 2D image cross-section of the brain  CT scans can resolve structures such as:  cerebral vasculature,  ventricles,  grey and white matter  some subcortical structures (e.g. thalamus and basal ganglia)  CT scans have confirmed a number of ideas about how the brain works in abnormal psych:  Schizophrenia and degenerative neurological disorders (e.g. Alzheimer’s disease) involve cortical atrophy – the number of brain cells or size of individual brain cells shrinks  Individuals with schizophrenia have smaller frontal lobes than do non-psychiatric controls  Autistic children show evidence of atrophy in the cerebellum  People suffering from bipolar disorders show some tissue loss throughout the brain  These findings often lacked specificity and were noted in a number of different disorders 2. Magnetic Resonance Imaging (MRI)  Magnetic resonance imaging – non-invasive technique, reveals both the structure and the functioning of the brain.  a strong homogeneous magnetic field is produced around the patient’s head  this field causes atoms with odd atomic weights to align their electrons parallel to the direction of the field  brief pulses of radio waves are introduced, causing electrons move in a characteristic gyroscopic manner  when radio waves are off, the electrons return to their original position, emitting them at their own frequency, which can then be detected outside a patient’s head  a magnetic gradient is used to determine the location of the radio source  Advantages:  capable of discriminating extremely small differences in water concentration  they are safe; it uses neither high-energy radiation (X-rays) nor injections  it avoids risks of overexposure and neurological complications  MRIs are now able to see results of decreased cortical volume seen in schizophrenia  Functional magnetic resonance imaging (fMRI) – provides dynamic view of metabolic changes occurring in the active brain  Schizophrenia patients with blunted affect showed significantly less activation in the prefrontal cortex, along with dysfunctional patterns of activation in the temporal lobe and midbrain, during emotional film excerpts, when compared with schizophrenia patients without blunted effect  This pattern of brain activity may represent the neural of blunted affect, because of impairments in the brain’s emotional processing circuitry located in those areas  MRI research is also being enhanced by scalp recordings of electrical activity (event-related potentials, or ERPs) and magnetic fields (MEG)  The ERP methodology is widely used; but finding the source of the electrical potential is difficult and the spatial resolution is low  MEG allows for a more precise determination of the source of activation because the brain is magnetically homogeneous 3. Positron Emission Tomography (PET)  Positron emission tomography – combination of computerized tomography and radioisotope imaging  The radiation is generated by injected or inhaled radioisotopes – common elements or substances that have had atom altered to be radioactive.  Isotopes with half-lives of minutes to hours are required for a PET scan  As the substance is used in the brain activity, radiation is given off and detected by the PET  This allows to measure a variety of biological activities  Providing a radioactive version of a ligand – a common molecule present in the chemical bonding that characterizes neurotransmission – allows the PET scan to show the distribution of various neurotransmitters within the brain  While CT scans and MRIs can produce static image of the brain’s anatomy, PET scans and fMRIs produce a dynamic image of the functioning brain.  Clinicians often use CT or MRI in addition to PET to determine the cause of structural abnormalities, such as reduced blood flow.  PET scans have confirmed that there are abnormal patterns of metabolic activity in people with:  Seizures, tumours, stroke, Alzheimer’s disease, Schizophrenia, OCD  They also show atypical patterns of cortical blood flow as they perform cognitive tasks  PET was used for individuals who were receiving cognitive-behaviour therapy (CBT) for depression  Patients were compared to an independent sample of individuals who had responded to a serotonin based antidepressant (paroxetine)  They found a distinct pattern of metabolic changes (in limbic and cortical regions) in patients who were in CBT compared to those who received antidepressants Neuropsychological Testing  Neuropsychological assessments are used to determine relationships between behaviour and brain function.  Bender Visual-Motor Gestalt Test – consists of a series of nine cards containing lines and shapes drawn in black on a piece of white cardboard. Respondents are asked to copy the images on another card and then to draw them from memory. o errors in reproducing these lines and shapes may indicate:  neurological problems,  but may also be caused by a tremor in the hand or,  by simple nervousness o certain types of errors are characteristic of neurological impairments:  rotation of figures  perseveration (e.g. continuing to copy a line past the scale of original pattern)  fragmentation  oversimplification  inability to copy angles  reversals  Disadvantages: o It produces many false negatives: some people with neurological impairments can complete the test with few errors. o Many normal younger children will make more errors than older children with brain damage o Bender is age-normed; results are compared to the results expected at a given age o The test-retest reliability coefficient is 0.70 with the scoring system, and clinicians can discriminate between unimpaired participants and those with neurological impairments ~77% of the time  by examining the pattern of results and deficits in performance, it’s possible to discriminate between various forms of organic damage  most popular battery is the Halstead-Reitan and Luria-Nebraska  Halstead-Reitan  studied patients with organic brain damage and consists of the following tests: 1. Category Test - Measures abstract thinking - examinee determines the principles that relate images varying in shape, size, location, colour, etc. - examinee is asked to choose, which ones represent the given category when shown images - performance on this test is believed to reflect frontal lobe functioning 2. Rhythm Test - test for concentration and attention - examinee listens to 30 pairs of tape-recorded rhythmic beats and is asked to identify which pairs are the same and different - performance on this is associated with right temporal lobe functioning 3. Tactual Performance Test - examinee is required to fit blocks of various shapes into corresponding spaces while blindfolded - examinee later draws the board from memory in order to test visual memory 4. Tapping Test - examinee taps rapidly on a lever 5. Grip Strength Test - examinee grasps a dynamometer, measuring grip strength - this test can help identify the location of brain damage 6. Auditory Test - examinee is asked to identify aurally transmitted nonsense of words P SYCHOLOGICAL A SSESSMENT Clinical Interviews  The clinical interview is the most common assessment tool, used by almost every clinician  It is an important and comfortable way to collect info about an individual during a psychological evaluation  The clinical interview provides meaningful context of an individual’s life  Practitioners would ask: Medical history, Psychiatric history, Age, marital status, family, education, lifestyle, etc.  Types of interviews: 1) Unstructured Interviews – tend to be open-ended affairs that allow interviewers to concentrate on a person’s unique style or on certain aspects of the presenting problem.  Advantages:  often known as free-flowing interview; clinician can follow the patient’s lead  it is relatively easy to avoid a sensitive topic until a patient is more at ease  they facilitate rapport – mutual trust and respect between people  Disadvantages:  Poor reliability and validity  Clinicians own theoretical orientation greatly influences the type of info sought  Clinicians may tend to uncover only info that fits their theoretical orientation and confirm their hypotheses 2) Structured Interviews – very specific in the order and wording of questions and in the rules governing the evaluation of responses  The DIS-IV is a highly structured interview that may be administered by both mental health professionals and trained lay interviewers  Developed for large-scale epidemiological research  The cost of paying professional diagnosticians is often prohibited  By increasing the standardization of a diagnostic interview, and requiring each question be read aloud verbatim, researchers are able to obtain the info they need without having to rely on the judgments of individual lay interviewers  Disadvantage: jeopardizes rapport 3) Semi-structured Interviews – the clinician has considerable leeway about what questions to ask, in what order, and with what wording  Questions are guided by an outline that lists certain dimensions of the patient’s functioning that need to be covered  Mental status examination – screens for patients’ emotional, intellectual, and neurological functioning  Used in formal diagnosis or to plan treatment  Many semi-structured are designed to look for specific problems, such as behaviour problems of childhood, depression, anxiety disorders, and personality disorders.  The most used to assess psychopathology is the Structured Clinical Interview for DSM-III and now DSM- IV-TR Assessment of Intelligence  Sir Francis Galton  conducted first scientific study of intellectual functioning to test the hypothesis that intelligence has a hereditary aspect. o Believed that pure intelligence could best be measured by studying physiological cues (e.g. speed of response) o This was the first attempt to demonstrate the biological correlates of intelligence  Alfred Binet  developed a means of determining which children should receive a public school education and which required special education. o He developed separate tests of judgment, comprehension, and reasoning o First to establish norms for the purpose of describing intelligence o Intelligence Quotient (QI) – child’s mental age, which was determined by child’s successful performance on age- grouped tests that has been normed, divided it by child’s chronological age, and multiplied the quotient by 100.  E.g. age = 14.8, mental age score = 15.6, IQ = (15.6/14.8 * 100) = 105 o Stanford-Binet Intelligence Scales – assesses five general kind of ability: fluid reasoning, knowledge, visual-spatial processing, quantitative reasoning, and working memory.  It produces separate scores for each of these functions as well as a global IQ score that summarizes the child’s ability o A person’s IQ is a function of how his/her score compares to others of the same age o The average be set at 100: those who perform more poorly have lower IQs  David Wechsler  Wechsler Adult Intelligence Scale (WAIS) – measures diverse aspects of intelligence including: o 10 core subsets, and o 5 supplementary subtests:  4 verbal comprehension tests:  general info, abstract thinking, capacity to recognize and act on well-learned societal rules and expectations, and vocab  3 working memory tests:  Short-term memory, arithmetic ability, and mental manipulations of symbols and numbers  5 perceptual reasoning tests:  Puzzles, reproduction of designs, manipulation of objects and symbols  3 processing speed tests:  Searching for visual items, copying patterns o Average intelligence on this scale is IQ of 100  The standard deviation – measure of how far from the mean an average score will fall – is 15  A score below 70 indicates mental retardation  A score above 130 indicate exceptional intelligence o Wechsler tools have very good t
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