Non-invasive neuroimaging in fetal alcohol spectrum disorders

Peer reviewed: YesNRC publication: Ye

Training children to reduce motion and increase success of MRI scanning

In this review, we outline interventions that can be used with children to prepare them for magnetic resonance imaging (MRI) and to limit their motion during medical imaging procedures. Children, especially those diagnosed with a developmental disability or other mental health challenges, may have difficulty remaining still for long periods of time. Children also experience fear, anxiety and curiosity in the MRI environment due to the noise, size of the machines, and overall overwhelming experience. These difficulties can affect the ability of researchers and other professionals to perform clinical tests such MRI, which require the child to remain motionless for the duration of the scan. A few studies have described methods used to prepare children for the MRI environment and train them for successful completion of the MRI scans. These include standard operating procedures as used in clinical scanning, such as appropriate information dissemination, standard physical restraint procedures and sedation. Other motion reduction techniques range from low-cost nontechnical but people heavy approaches, such as mock scanner training sessions, systematic desensitization and guided imagery techniques to more technical engineering type approaches, such as behavior feedback methods and the use of postprocessing motion correction algorithms.Peer reviewed: YesNRC publication: Ye

MRI research proposals involving child subjects: Concerns hindering Research Ethics Boards from approving them and a checklist to help evaluate them

The process of research is often lengthy and can be extremely arduous. It may take many years to proceed from the initial development of an idea through to the comparison of the new modalities against a current gold-standard practice. Each step along the way involves rigorous scientific review, where protocols are scrutinized by multiple scientists not only in the specific field at hand but related fields as well. In addition to scientific review, most countries require a further review by a panel that will specifically address the ethics of the proposed research. In Canada, those panels are referred to as Research Ethics Boards (REB), with the United States counterparts known as Institutional Review Boards (IRB).Peer reviewed: YesNRC publication: Ye

Reactions of young children to the MRI scanner environment

Seventy children aged 2 to 7 years were exposed to the MR imaging environment through a series of steps typical of a research study. Their willingness to proceed through the process was used to estimate the prevalence of fear. Thirty-seven children (53%, 95% CI [41%, 65%]) completed the approach sequence. Although the correlation of child age in months (M = 60.1, SD = 16.5, N = 70) and highest successful step (M = 5.8, SD = 2.6, 95% CI [5.2, 6.4]) completed was not statistically significant at the 0.05 level, r(68) = 0.21, p = 0.08, 95% CI [-0.03, 0.42], the proportion of children aged 6-7 yrs who successfully completed all steps (14 of 21, 67%, 95% CI [50%, 84%]) was significantly different from the proportion of children aged 2-3 yrs who completed all steps (6 of 23, 26%, 95% CI [11%, 41%]), (Fisher's Exact Test, two-tailed P = 0.0148). A failure rate of at least 50% should be included into group size calculations when performing studies with young children (2-7 years), in addition to motion and other experimental factors.Peer reviewed: YesNRC publication: Ye

Functional magnetic resonance imaging of the spinal cord during sensory stimulation in diabetic rats

PURPOSE: To determine if differences exist between control and diabetic rats in functional magnetic resonance imaging (fMRI) activity of the spinal cord and if fMRI can provide a means of early detection of diabetic neuropathy. MATERIALS AND METHODS: fMRI of the spinal cord, using noxious electrical stimulation (15 V ( approximately 8 mA), 0.3 msec, 3 Hz) of the hind paw, was performed in groups of control and streptozotocin (STZ)-induced type 1 diabetic rats. RESULTS: Diabetic rats were lighter, hyperglycemic, and had lower blood pH than controls. fMRI activity at the lumbar enlargement of the spinal cord was identified in the dorsal horn ipsilateral to stimulus of all animals. Signal intensity changes across the lumbar spinal cord during periods of activity were not significantly different between control and diabetic rats, with a trend toward greater signal changes in controls. When specific regions of the spinal cord were analyzed, control rats exhibited significantly increased blood-oxygen level-dependent (BOLD) fMRI activity in both ipsilateral and contralateral dorsal horn compared to diabetic rats. CONCLUSION: The results of this study are consistent with reports that primary afferent input to the spinal cord is diminished by diabetes, and suggest that BOLD fMRI may be useful in early detection of diabetic neuropathy.Peer reviewed: YesNRC publication: Ye

Functional evaluation of hidden figures object analysis in children with autistic disorder

Functional magnetic resonance imaging (fMRI) during performance of a hidden figures task (HFT) was used to compare differences in brain function in children diagnosed with autism disorder (AD) compared to children with attention-deficit/hyperactivity disorder (ADHD) and typical controls (TC). Overall greater functional MRI activity was observed in the two control groups compared to children with AD. Laterality differences were also evident, with AD subjects preferentially showing activity in the right medial temporal region while controls tended to activate the left medial temporal cortex. Reduced fMRI activity was observed in the parietal, ventral-temporal and hippocampal regions in the AD group, suggesting differences in the way that children with AD process the HFT.Peer reviewed: YesNRC publication: Ye

Comparison of spatial working memory in children with prenatal alcohol exposure and those diagnosed with ADHD; A functional magnetic resonance imaging study

<p>Abstract</p> <p>Background</p> <p>Alcohol related neurodevelopmental disorder (ARND) falls under the umbrella of fetal alcohol spectrum disorder (FASD), but individuals do not demonstrate the facial characteristics associated with fetal alcohol syndrome (FAS), making diagnosis difficult. While attentional problems in ARND are similar to those found in attention-deficit/hyperactivity disorder (ADHD), the underlying impairment in attention pathways may be different.</p> <p>Methods</p> <p>Functional magnetic resonance imaging (fMRI) of a working memory (1-back) task of 63 children, 10 to 14 years old, diagnosed with ARND and ADHD, as well as typically developing (TD) controls, was conducted at 3 T. Diffusion tensor imaging (DTI) data were also acquired.</p> <p>Results</p> <p>Activations were observed in posterior parietal and occipital regions in the TD group and in dorsolateral prefrontal and posterior parietal regions in the ARND group, whereas the ADHD group activated only dorsolateral prefrontal regions, during the working memory component of the task (1-back minus 0-back contrast). The increases in frontal and parietal activity were significantly greater in the ARND group compared to the other groups. This increased activity was associated with reduced accuracy and increased response time variability, suggesting that ARND subjects exert greater effort to manage short-term memory load. Significantly greater intra-subject variability, demonstrated by fMRI region-of-interest analysis, in the ADHD and ARND groups compared to the TD group suggests that moment-to-moment lapses in attention contributed to their poorer task performance. Differences in functional activity in ARND subjects with and without a diagnosis of ADHD resulted primarily from reduced activation by the ARND/ADHD + group during the 0-back task. In contrast, children with ADHD alone clearly showed reduced activations during the 1-back task. DTI analysis revealed that the TD group had significantly higher total tract volume and number of fibers than the ARND group. These measures were negatively correlated with errors on the 1-back task, suggesting a link between white matter integrity and task performance.</p> <p>Conclusions</p> <p>fMRI activations suggest that the similar behavior of children with ARND and ADHD on a spatial working memory task is the result of different cognitive events. The nature of ADHD in children with ARND appears to differ from that of children with ADHD alone.</p