Evaluating the Impact of Genetic Counseling and Testing with Signal Detection Methods

One measure of the impact of genetic counseling and testing (GCT) is the extent to which it fosters behavioral change that is consistent with mutation status. We describe and illustrate how two different signal detection methods, receiver operating characteristic (ROC) analysis and recursive partitioning, can be used in this context to evaluate the impact of GCT. We analyzed real screening behavior data obtained in the 12 months following GCT for Hereditary Nonpolyposis Colon Cancer (HNPCC) using these two different signal detection approaches. Each approach demonstrated that GCT had an impact on behavioral outcomes, and was effective in fostering behavioral outcomes appropriate to mutation status. The ROC approach demonstrated that GCT was effective because mutation positive and mutation negative individuals could be distinguished on the basis of the number of recommended screening behaviors. The recursive partitioning approach demonstrated that GCT was effective because there were generally high rates of adherence to screening guidelines among subjects. The recursive partitioning technique also identified four subgroups of subjects, each with distinct characteristics, for which tailored interventions could be developed to increase rates of adherence to screening guidelines. Signal detection methods are easily implemented and are useful techniques for evaluating the impact of GCT.     

The role of metabotropic glutamate receptors and cortical adaptation in habituation of odor-guided behavior

Decreases in behavioral investigation of novel stimuli over time may be mediated by a variety of factors including changes in attention, internal state, and motivation. Sensory cortical adaptation, a decrease in sensory cortical responsiveness over prolonged stimulation, may also play a role. In olfaction, metabotropic glutamate receptors on cortical afferent pre-synaptic terminals have been shown to underlie both cortical sensory adaptation and habituation of odor-evoked reflexes. The present experiment examined whether blockade of sensory cortical adaptation through bilateral infusion of the group III metabotropic glutamate receptor antagonist cyclopropyl-4-phosphonophenylglycine (CPPG) into the anterior piriform cortex could reduce habituation of a more complex odor-driven behavior such as investigation of a scented object or a conspecific. The results demonstrate that time spent investigating a scented jar, or a conspecific, decreases over the course of a continuous 10 minute trial. Acute infusion of CPPG bilaterally into the anterior piriform cortex significantly enhanced the time spent investigating the scented jar compared to investigation time in control rats, without affecting overall behavioral activity levels. Infusions into the brain outside of the piriform cortex were without effect. CPPG infusion into the piriform cortex also produced an enhancement of time spent investigating a conspecific, although this effect was not significant.     

Laboratory behavioral measures of impulsivity

Previous research and theory have conceptualized impulsivity as a multifaceted construct that requires multiple modes of measurement for accurate assessment. This article describes a software package that includes four paradigms for measuring multiple and unique aspects of impulsivity. Specifically, four tasks are described: (1) the two choice impulsivity paradigm, (2) the single key impulsivity paradigm, (3) the GoStop impulsivity paradigm, and (4) the time paradigm. These tasks measure processes related to the capacity to tolerate delay for reward, to inhibit an already initiated response, and to estimate the passage of time. These processes have been found to be important to the understanding of impulsive behaviors. The programs are flexible and allow the experimenter to manipulate a number of parameters related to delay-reward contingencies, timing, performance feedback/payment, and data output variables. Manipulation of these parameters makes the paradigms scalable to a wide range of ability levels and appropriate for samples ranging from children to adults. The four paradigms in this software package are available at no cost and can be obtained by contacting the corresponding author.     

Possible influence of linguistic musical background on perceptual pitch-matching tasks: a pilot study

Linguistic background has been identified as important in the perception of pitch, particularly between tonal versus nontonal languages. In addition, a link between native language and the perception of musical pitch has also been established. This pilot study examined the perception of pitch between listeners from tonal and nontonal linguistic cultures where two different styles of music originate. Listeners were 10 individuals born in China who ranged in age from 25 to 37 years and had spent on the average 30 mo. in the USA and 10 individuals, born on the Indian subcontinent, who ranged in age from 22 to 31 years, and had spent an average of 13 mo. in the USA. Listeners from both groups participated in two conditions. One condition involved listening to a selection of music characteristic of the individual's culture (China, pentatonic scale; Indian subcontinent, microtones), and one condition involved no music. All listeners within each condition participated in two voice pitch-matching tasks. One task involved matching the lowest and highest pitch of tape-recorded voices to a note on an electronic keyboard. Another task involved matching the voice pitch of tape-recorded orally read words to a note on the keyboard. There were no differences between the two linguistic groups. Methodological limitations preclude generalization but provide the basis for further research.     

Rapid processing of cast and attached shadows

We used a visual-search method to investigate the role of shadows in the rapid discrimination of scene properties. Targets and distractors were light or dark 2-D crescents of identical shape and size, on a mid-grey background. From the dark stimuli, illusory 3-D shapes can be created by blurring one arc of the crescent. If the inner arc is blurred, the stimulus is perceived as a curved surface with attached shadow. If the outer arc is blurred, the stimulus is perceived as a flat surface casting a shadow. In a series of five experiments, we used this simple stimulus to map out the shadow properties that the human visual system can rapidly detect and discriminate. To subtract out 2-D image factors, we compared search performance for dark-shadow stimuli with performance for light-shadow stimuli which generally do not elicit strong 3-D percepts. We found that the human visual system is capable of rapid discrimination based upon a number of different shadow properties, including the type of the shadow (cast or attached), the direction of the shadow, and the displacement of the shadow. While it is clear that shadows are not simply discounted in rapid search, it is unclear at this stage whether rapid discrimination is acting upon shadows per se or upon representations of 3-D object shape and position elicited by perceived shadows.     

No pause for a brief disruption: failures of visual awareness during ongoing events

Past research has repeatedly documented the close relationship between visual attention and awareness. Most recently, research exploring change blindness, inattentional blindness, repetition blindness, and the attentional blink has converged on the conclusion that attention to one aspect of a scene or event may lead to a highly circumscribed awareness of only the specific information attended, while other information, even that which is spatially or temporally nearby can go completely unnoticed. In the present report, we extend these observations to the dynamic allocation of attention during a well-structured meaningful event. In two experiments, subjects viewed brief videos of simple events and were told to pay close attention to them. During the events, an unexpected disruption consisting of a brief low spatial frequency motion field occurred. Despite intensive questioning and opportunities for recognition, the majority of subjects reported no awareness of 200, 400, or 600 ms disruptions. In a second experiment, blank-screen disruptions were added, and these resulted in no increase in detection. We conclude that visual attention may result in far more transitory awareness of visual information than previously appreciated.     

Quality of life of adolescent males with attention-deficit hyperactivity disorder

Most psychosocial research on attention-deficit/hyperactivity disorder (ADHD) has focused on deficits in school, family, or behavioral functioning without incorporating perceived quality of life (QoL) or the adolescents' perspective. The Youth Quality of Life Instrument--Research Version (YQOL-R), was used to assess self-perceived QoL in a community sample of adolescents aged 11-18 years. Fifty-five adolescent males with a clinical diagnosis of ADHD were compared to a group of 107 adolescents with no chronic conditions (NCC) and a group of 52 adolescents with mobility impairments (MI). The adolescents with ADHD reported significantly lower perceived QoL scores, particularly in the Self and Relationship domains, than the NCC group. Their scores were similar to those from the group with MI, a group previously shown to have a substandard QoL. Interventions to improve self-esteem and social interactions might use QoL outcomes in evaluating effectiveness.     

Impact of recent findings on study design of future autism clinical trials

There are specific challenges to studying the design of pharmacologic trials in child/adolescent and adult autism, such as subject stratification and parallel versus crossover designs. This article describes how optimal study design is influenced by subject selection and outcome measures chosen. Lessons learned in study design from the Research Units on Pediatric Psychopharmacology Autism Network trial with risperidone, Seaver Center trials with fluoxetine and valproate, Dartmouth trials with amantadine, and National Institutes of Health secretin trials are highlighted. The Internet System for Assessing Autistic Children system for managing multicenter clinical trials in autism and statistical issues in autism research are also described.     

College students and HIV/AIDS: more insights on knowledge, testing, and sexual practices

In this study, the authors confirm and expand previous findings (M. Anastasi, R. G. Sawyer, & P. J. Pinciaro, 1999; J. E. Lewis & R. M. Malow, 1997) concerning college students' knowledge and perceptions about HIV/AIDS. Although students are knowledgeable about HIV/AIDS, they have little personal concern about becoming infected and do not take appropriate safe sex precautions. Findings of the present study show that gender, ethnic background, and knowing someone infected by HIV/AIDS influence students' level of concern about infection. In addition, older students and those who know someone infected by HIV/AIDS are more likely to have been tested. Results are compared with national surveys of other age groups, and the authors suggest specific intervention strategies for college students.