The presence of executive deficits in patients with Obstructive Sleep Apnoea

Obstructive sleep apnoea (OSA) is a chronic condition in which the upper airways collapse repeatedly during sleep, completely or partially obstructing breathing. This obstruction leads to chronic intermittent hypoxia and severe sleep fragmentation, disrupting the restorative functions of sleep. Beebe and Gozal (2002)a developed a theory which hypothesises that disruption of the restorative functions of sleep lead to a chronic low level brain damage most evident in executive functions (EF). Neuropsychological testing of EF, volumetric MRI, magnetic resonance spectroscopy, event related potentials and CSF biomarkers all provide support for this theory. Little research has been done to explore the nature of the subjective complaint and it’s impact on the activities of daily living.

Do repeated rumble strip hits improve driver alertness?

Driving while sleepy is associated with increased crash risk. Rumble strips are designed to alert a sleepy or inattentive driver when they deviate outside their driving lane. The current study sought to examine the effects of repeated rumble strip hits on levels of physiological and subjective sleepiness as well as simulated driving performance. In total, 36 regular shift workers drove a high-fidelity moving base simulator on a simulated road with rumble strips installed at the shoulder and centre line after a working a full night shift. The results show that on average, the first rumble strip occurred after 20 minutes of driving, with subsequent hits occurring 10 minutes later, with the last three occurring approximately every 5 minutes thereafter. Specifically, it was found that the first rumble strip hit reduced physiological sleepiness; however, subsequent hits did not increase alertness. Moreover, the results also demonstrate that increased subjective sleepiness levels, via the Karolinska Sleepiness Scale, were associated with a greater probability of hitting a rumble strip. The present results suggest that sleepiness is very resilient to even strongly arousing stimuli, with physiologicl and subjective sleepiness increasing over the duration of the drive, despite the interference by rumble strips.

Meta-analysis of structural imaging findings in Attention-Deficit/Hyperactivity Disorder

Background Although there are many structural neuroimaging studies of attention-deficit/hyperactivity disorder (ADHD) in children, there are inconsistencies across studies and no consensus regarding which brain regions show the most robust area or volumetric reductions relative to control subjects. Our goal was to statistically analyze structural imaging data via a meta-analysis to help resolve these issues. Methods We searched the MEDLINE and PsycINFO databases through January 2005. Studies must have been written in English, used magnetic resonance imaging, and presented the means and standard deviations of regions assessed. Data were extracted by one of the authors and verified independently by another author. Results Analyses were performed using STATA with metan, metabias, and metainf programs. A meta-analysis including all regions across all studies indicated global reductions for ADHD subjects compared with control subjects, standardized mean difference equal to .408, p less than .001. Regions most frequently assessed and showing the largest differences included cerebellar regions, the splenium of the corpus callosum, total and right cerebral volume, and right caudate. Several frontal regions assessed in only two studies also showed large significant differences. Conclusions This meta-analysis provides a quantitative analysis of neuroanatomical abnormalities in ADHD and information that can be used to guide future studies.

Using pharmacogenetics and pharmacogenomics in the treatment of psychiatric disorders: some ethical and economic considerations"

Current pharmacotherapies for psychiatric disorders are generally incompletely effective. Many patients do not respond well or suffer adverse reactions to these drugs, which can result in poor patient compliance and poor treatment outcome. Adverse drug reactions and non-response are likely to be influenced by genetic polymorphisms. Pharmacogenetics holds some promise for improving the treatment of mood disorders by utilising information about genetic polymorphisms to match patients to the drug therapy that is the most effective with the fewest side effects. Pharmacogenomics promises to facilitate the development of new drugs for treatment. However, these technologies raise many ethical, economic and regulatory issues that need to be addressed before they can be integrated into psychiatry, and medicine more generally. We discuss ethical and policy issues arising from pharmacogenetic testing and pharmacogenomics research, such as informed consent, privacy and confidentiality, research on vulnerable persons and discrimination; and economic viability of pharmacogenetics and pharmacogenomics. We conclude with recommendations for the regulation and distribution of pharmacogenetic testing services and pharmacogenomic drugs.

Covariation and interference between physiological reflexes: Eye-blink startle cardiac defense, and skin conductance

Comparative studies of autonomic and somatic reflexes, such as cardiac defense and motor startle, are rare. However, examination of the pattern of covariation, independence, or interference among physiological reflexes may help to clarify their functional significance and elucidate their complex modulation by psychological factors. Here we report the results of a study that examined the pattern of interference of eye-blink startle on subsequent cardiac defense. Participants were 63 students (31 women) distributed into three groups according to the sensory modality of the eliciting stimulus during the startle trials: acoustic high intensity (105 dB), acoustic low intensity (65 dB), and visual modality. Startle trials consisted of 12 presentations of the eliciting stimulus with a duration of 50 ms, instantaneous risetime, and a variable inter-stimulus interval of 16 – 20 s.Defense trials began 20 s after the last startle trial and consisted, for all groups, of 3 presentations of the high intensity acoustic stimulus with a duration of 500 ms and an inter-stimulus interval of 215 s. Results showed a clear interference of the startle trials on the subsequent defense trials when both types of trials shared identical sensory modality (acoustic) independently of intensity: the expected pattern of cardiac defense in the first trial only appeared in the visual modality. Similar interference effects were observed in the skin conductance response. Subjective reactivity to the defense stimulus did not detect differences between conditions.

Psychometric assessment of recovery from mild traumatic brain injury

The Rapid Screen of Concussion (RSC) is a brief psychometric test battery, designed to provide a functional criterion to aid clinical diagnosis of mild traumatic brain injury (mTBI). The present research aimed to examine the utility of this instrument for assessing recovery after mTBI. Three studies were conducted. In Study 1, Discriminant Function Analysis was performed to determine how well the RSC differentiated uninjured controls (N¼16), from mTBI patients (N¼22) and moderate to severe TBI patients (N¼14), several months post-injury. As predicted, moderate to severe TBI patients achieved lower scores than the mTBI and control groups. The RSC also successfully differentiated between each of the diagnostic groups, yielding an overall correct classification rate of 75%. Study 2 examined the predictive utility of the RSC in the mTBI sample (N¼22). Acute injury performance on the RSC was correlated with post-injury scores at an average of 5.5 months post-injury. Statistically significant partial correlation coefficients (r¼0.53r¼0.80) were found for each of the subtests, showing that low acute RSC scores were predictive of poor recovery scores on the RSC after mTBI. In the third study, Reliable Change Indices were calculated on the RSC subtests to examine individual patterns of recovery from mTBI. While 17 of the 23 participants made a significant improvement on their acute injury DSST scores (74%), only 13 of 25 made a significant improvement on the Rapid Sentence Judgement Test (52%), highlighting differential recovery of function, and challenging the notion of full recovery from mTBI within 3 months. These overall results offer support for the construct and predictive validity of the RSC and demonstrate that inexpensive tests of brain function may be useful for managing mTBI acutely for prognosis.

Verbal recall after mild traumatic brain injury: Sensitivity of the rapid screen of concussion

The present study aimed to determine whether including a sensitive test of immediate and delayed recall would improve the diagnostic validity of the Rapid Screen of Concussion (RSC) in mild Traumatic Brain Injury (mTBI) versus orthopaedic clinical samples. Two studies were undertaken. In Study 1, the performance of 156 mTBI and 145 orthopaedic participants was analysed to identify the number of individuals who performed at ceiling on the verbal memory subtest of the RSC, as this test required immediate and delayed recall of only five words. A second aim was to determine the sensitivity and specificity levels of the RSC. Study 2 aimed to examine whether replacement of the verbal memory subtest with the 12-word Hopkins Verbal Learning Test (HVLT) could improve the sensitivity of the RSC in a new sample of 26 mTBI and 30 orthopaedic participants. Both studies showed that orthopaedic participants outperformed mTBI participants on each of the selected measures. Study 1 showed that 14% of mTBI participants performed at ceiling on the immediate and 21.2% on delayed recall test. Performance on the original battery yielded a sensitivity of 82%, specificity of 80% and overall correct classification of 81.5% participants. In Study 2, inclusion of the HVLT improved sensitivity to a level of 88.5%, decreased specificity to a level of 70% and resulted in an overall classification rate of 80%. It was concluded that although inclusion of the five-word subtest in the RSC can successfully distinguish concussed from non-concussed individuals, use of the HVLT in this protocol yields a more sensitive measure of subtle cognitive deficits following mTBI.

Investigation of psychological and neuropsychological factors associated with clinical outcome following a group rehabilitation programme

The present study investigated neuropsychological and psychological factors associated with successful treatment outcome following a group intervention for individuals with acquired brain injury (ABI). Participants were classified into two groups (Clinically Improved and Not Improved) based upon the findings of a previous study (Ownsworth, McFarland, & Young, 2000a). A discriminant analysis was used to predict group membership on three outcome measures (Awareness and Strategy Behaviour indices of the Self-Regulation Skills Interview and the Psychosocial Dimension of the Sickness Impact Profile) between pre-assessment and post-assessment, and between pre-assessment and 6 months follow-up. Neuropsychological factors involved measures of executive functioning and psychological factors were assessed using measures of personality-related denial and coping-related denial. Overall, the results indicated that individuals with impaired executive functioning were most likely to be classified as Clinically Improved on measures of awareness, strategy behaviour and psychosocial functioning. Individuals who deny or minimise their ABI symptoms were less likely to improve their psychosocial functioning following the group intervention. Future research needs to evaluate interventions for enhancing self-regulation skills and improving psychosocial functioning for individuals who employ denial as a main strategy for coping following ABI.

Double cross-validation and improved sensitivity of the rapid screen of mild traumatic brain injury

This study aimed to replicate and cross-validate the Rapid Screen of Concussion (RSC) for diagnosing mild TBI (mTBI). One hundred (81 male, 19 female) cases of mTBI and 35 (23 male and 12 female) cases of orthopaedic injuries were tested within 24 hr of injury. Double cross-validation was used to examine whether total RSC scores obtained in the cur-rent sample, generalised to one previously reported. In the new sample, mTBI patients answered fewer orientation questions, recalled fewer words on the learning trial and after a delay, judged fewer sentences in 2 min, and completed fewer symbols in the Digit Symbol Substitution Test than orthopaedic controls. The formulae and cut-offs developed on the original and new samples produced similar sensitivity and overall correct classification rates. Inclusion of the Digit Symbol Substitution Test performance of the new sample improved the sensitivity (80.2%) and specificity (82.6%) in males. It did not improve the correct classification rate in females, which was 89.5% sensitivity and 91.7% specificity before the inclusion of the Digit Symbol Substitution Test. Taken together, these results indicate that a combined score on this 12-min screen yields a measure of level of brain impairment up to 24 hr after mTBI.

How primatology can inform us about the evolution of the humand mind

Humans are primates. We have evolved from common ancestors and the evolution of the human body is becoming increasingly clear as the archeological record expands. But for most people the gap between humans and animals lies in the mind, not in the body. And minds do not fossilise. To reconstruct the evolution of mind, scholars have thus increasingly looked to our closest relatives for clues. Here I discuss four ways in which the study of primates may inform such reconstruction: fact-finding, phylogenetic reconstruction, analogy, and regression models. Knowledge about primates can help us bridge the gap. Extinction of our closest relatives, on the other hand, would not only deplete that source of information but also increase the apparent differences between animal and human minds. It is likely that we have a long history of displacing closely related species, including the other hominids, leading us to appear ever more unique.

Visual-auditory integration during speech imitation in autism

Children with autistic spectrum disorder (ASD) may have poor audio-visual integration, possibly reflecting dysfunctional 'mirror neuron' systems which have been hypothesised to be at the core of the condition. In the present study, a computer program, utilizing speech synthesizer software and a 'virtual' head (Baldi), delivered speech stimuli for identification in auditory, visual or bimodal conditions. Children with ASD were poorer than controls at recognizing stimuli in the unimodal conditions, but once performance on this measure was controlled for, no group difference was found in the bimodal condition. A group of participants with ASD were also trained to develop their speech-reading ability. Training improved visual accuracy and this also improved the children's ability to utilize visual information in their processing of speech. Overall results were compared to predictions from mathematical models based on integration and non-integration, and were most consistent with the integration model. We conclude that, whilst they are less accurate in recognizing stimuli in the unimodal condition, children with ASD show normal integration of visual and auditory speech stimuli. Given that training in recognition of visual speech was effective, children with ASD may benefit from multi-modal approaches in imitative therapy and language training. (C) 2004 Elsevier Ltd. All rights reserved.