Topography of somatosensory processing: cerebral lateralization and focused attention.

Healthy dextrals underwent fMRI during a task of graphesthesia requiring detection of any number written consecutively from an otherwise random number sequence. Test conditions included (1) focus on unilateral right hand stimuli, (2) focus on unilateral left hand stimuli, (3) focus on right hand only during bilateral hand stimulation, (4) focus on left hand only during bilateral hand stimulation, and (5) rest. Attention to unilateral hand stimulation produced bihemispheric activation with minimal or no activation of ipsilateral primary sensorimotor region. Attention to unilateral left hand stimuli resulted in more activation than attention to unilateral right hand stimuli. Stimulation of the nonattended hand activated the contralateral somatosensory area, but to a lesser spatial extent than attended stimuli. Comparing focused attention to the left versus right side during identical sensory inputs (i.e., bilateral hand stimulation), focused attention to the right hand increased activation in the left somatosensory region, but focused attention to the left hand increased activation in both cerebral hemispheres. Thus, focused attention to unilateral somatosensory stimuli produces bilateral cerebral activation, but the increase in blood flow is greater in the contralateral hemisphere. Unattended stimuli activate the contralateral primary somatosensory area. Left/right asymmetries were demonstrated consistent with cerebral lateralization.     

Eradication of a large outbreak of a single strain of vanB vancomycin-resistant Enterococcus faecium at a major Australian teaching hospital.

OBJECTIVE: To demonstrate that nosocomial transmission of vancomycin-resistant enterococci (VRE) can be terminated and endemicity prevented despite widespread dissemination of an epidemic strain in a large tertiary-care referral hospital. INTERVENTIONS: Two months after the index case was detected in the intensive care unit, 68 patients became either infected or colonized with an epidemic strain of vanB vancomycin-resistant Enterococcus faecium despite standard infection control procedures. The following additional interventions were then introduced to control the outbreak: (1) formation of a VRE executive group; (2) rapid laboratory identification (30 to 48 hours) using culture and polymerase chain reaction detection of vanA and vanB resistance genes; (3) mass screening of all hospitalized patients with isolation of carriers and cohorting of contacts; (4) environmental screening and increased cleaning; (5) electronic flagging of medical records of contacts; and (6) antibiotic restrictions (third-generation cephalosporins and vancomycin). RESULTS: A total of 19,658 patient and 24,396 environmental swabs were processed between July and December 2001. One hundred sixty-nine patients in 23 wards were colonized with a single strain of vanB vancomycin-resistant E. faecium. Introducing additional control measures rapidly brought the outbreak under control. Hospital-wide screening found 39 previously unidentified colonized patients, with only 7 more nonsegregated patients being detected in the next 2 months. The outbreak was terminated within 3 months at a cost of dollar 2.7 million (Australian dollars). CONCLUSION: Despite widespread dissemination of VRE in a large acute care facility, eradication was achievable by a well-resourced, coordinated, multifaceted approach and was in accordance with good clinical governance.     

Work hours regulations for house staff in psychiatry: bad or good for residency training?

OBJECTIVE: The movement to limit work hours for house staff has gained momentum in recent years. The authors set out to review the literature on work hours reform, particularly as it applies to psychiatric residency training, and to provide two different viewpoints on the controversy. METHODS: The authors present the historical background of work hours reform in the United States and review recent literature about resident work hours limitations. Using a debate format, the authors discuss whether the new regulations are having a positive or negative impact on residency training in psychiatry. RESULTS: Drs. Lomonaco and Auchincloss argue that currently-existing work hours restrictions may have unintended consequences for the health of patients and an untoward impact on residents' professional development and academic medicine's overall structure. Dr. Rasminsky argues that work hours restrictions do not go far enough in protecting residents and patients from the harmful effects of fatigue, and that our definition of professionalism needs to be reexamined in light of emerging scientific literature. CONCLUSION: There should be some limitation on resident work hours, with exact numbers to be determined by growing scientific knowledge about the effects of prolonged wakefulness. More study is needed, particularly in the area of psychiatric residency training.     

Corticomotor excitability of back muscles is affected by intervertebral disc lesion in pigs

Morphological and behavioural changes in back muscles are common in back pain and injury. Recent data indicate a rapid reduction in the size of the multifidus, a deep back muscle, within 3 days of experimental intervertebral disc (IVD) injury in pigs. A reduced neural drive may contribute to this. We investigated changes in corticomotor excitability following IVD lesion by evaluation of the response of back muscles to electrical stimulation of the motor cortex. Motor evoked potentials (MEPs) were studied in 12 Swedish landrace pigs before injury, immediately after abdominal incision, immediately after L3-4 IVD lesion with a scalpel, and 15 min later. In two animals, responses were also evoked by descending volleys excited at the level of the mastoid processes (cervicomedullary evoked potentials) without motor cortex activation. In five animals, a sham procedure was followed without IVD lesion. MEPs were recorded in short (deep) and long (superficial) fibres of the multifidus at L3-5 on the lesioned side and at L4 contralaterally with intramuscular wire electrodes. Although the MEP amplitude increased in several muscles after incision, at 15 min after IVD lesion only the MEP amplitude of the deep L4 multifidus on the lesioned side was increased [36% (SD 15%), P  < 0.05]. There were no changes in MEP amplitude after 15 min at adjacent or contralateral levels. The response to cervicomedullary stimulation reduced slightly. This suggests that the increased MEP amplitude was due to changes in cortical excitability. These data indicate that IVD lesion induces localized increases, and not decreases, in the excitability of cortical inputs to the deep paraspinal muscles that cross a lesioned disc.     

Randomized Controlled Trial of a Paraprofessional-Delivered In-Home Intervention for Young Reservation-Based American Indian Mothers

ObjectiveTo evaluate the efficacy of a paraprofessional-delivered, home-visiting intervention among young, reservation-based American Indian (AI) mothers on parenting knowledge, involvement, and maternal and infant outcomes.MethodFrom 2002 to 2004, expectant AI women aged 12 to 22 years (n = 167) were randomized (1:1) to one of two paraprofessional-delivered, home-visiting interventions: the 25-visit “Family Spirit” intervention addressing prenatal and newborn care and maternal life skills (treatment) or a 23-visit breast-feeding/nutrition education intervention (active control). The interventions began during pregnancy and continued to 6 months postpartum. Mothers and children were evaluated at baseline and 2, 6, and 12 months postpartum. Primary outcomes included changes in mothers' parenting knowledge and involvement. Secondary outcomes included infants' social and emotional behavior; the home environment; and mothers' stress, social support, depression, and substance use.ResultsParticipants were mostly teenaged, first-time, unmarried mothers living in reservation communities. At 6 and 12 months postpartum, treatment mothers compared with control mothers had greater parenting knowledge gains, 13.5 (p < .0001) and 13.9 (p < .0001) points higher, respectively (100-point scale). At 12 months postpartum, treatment mothers reported their infants to have significantly lower scores on the externalizing domain (β = ?.17, p < .05) and less separation distress in the internalizing domain (β = ?.17, p < .05). No between-group differences were found for maternal involvement, home environment, or mothers' stress, social support, depression, or substance use.ConclusionsThis study supports the efficacy of the paraprofessional-delivered Family Spirit home-visiting intervention for young AI mothers on maternal knowledge and infant behavior outcomes. A longer, larger study is needed to replicate results and evaluate the durability of child behavior outcomes. J. Am. Acad. Child Adolesc. Psychiatry, 2009;48(6):591-601.     

Noninvasive assessment of endothelial activity in patients with peripheral arterial disease and cardiovascular risk factors.

Microvascular endothelial activity (EA) after stimulation with iontophoretically administered acetylcholine was evaluated using laser Doppler fluxmetery (LDF) and calibrated photoplethysmography (c-PPG) in normal patients and patients with peripheral artery disease (PAD). The patients included 79 non-PAD subjects and 51 patients with PAD. Upper and lower extremity EA was examined using LDF and c-PPG after acetylcholine iontophoresis for 10 min. Sensitivity and specificity were assessed using integrated area under response curve. In non-PAD patients, the EA by LDF in the upper extremity was significantly lower in the older patients compared to the younger patients. Conversely, EA by LDF detected no significant difference between these groups in the lower extremity.With c-PPG, the EA was slightly reduced in the upper but not in the lower extremity in older patients. Comparing PAD patients to the older patients, there was a significantly lower EA response in the upper and lower extremities by LDF. Likewise, c-PPG detected a highly significantly reduced EA in the upper and lower extremities for PAD patients. These results indicated that using a noninvasive technique to determine EA, there were significant differences in the EA response to acetylcholine between those with PAD and normal patients over the age of 50. Importantly, the EA response was reduced in the upper and lower extremities, indicating systemic disease of the endothelium in PAD patients.