Cortical and subcortical functional connectivity and cognitive impairment in Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative disease with cognitive as well as motor impairments. While much is known about the brain networks leading to motor impairments in PD, less is known about the brain networks contributing to cognitive impairments. Here, we leveraged resting-state functional magnetic resonance imaging (rs-fMRI) data from the Parkinson's Progression Marker Initiative (PPMI) to examine network dysfunction in PD patients with cognitive impairment. We focus on canonical cortical networks linked to cognition, including the salience network (SAL), frontoparietal network (FPN), and default mode network (DMN), as well as a subcortical basal ganglia network (BGN). We used the Montreal Cognitive Assessment (MoCA) as a continuous index of coarse cognitive function in PD. In 82 PD patients, we found that lower MoCA scores were linked with lower intra-network connectivity of the FPN. We also found that lower MoCA scores were linked with lower inter-network connectivity between the SAL and the BGN, the SAL and the DMN, as well as the FPN and the DMN. These data elucidate the relationship of cortical and subcortical functional connectivity with cognitive impairments in PD.

Salience network and cognitive impairment in Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative disease with cognitive as well as motor impairments. While much is known about the brain networks leading to motor impairments in PD, less is known about the brain networks contributing to cognitive impairments. Here, we leveraged resting-state functional magnetic resonance imaging (rs-fMRI) data from the Parkinson's Progression Marker Initiative (PPMI) to examine network dysfunction in PD patients with cognitive impairment. We tested the hypothesis that cognitive impairments in PD involve altered connectivity of the salience network (SN), a key cortical network that detects and integrates responses to salient stimuli. We used the Montreal Cognitive Assessment (MoCA) as a continuous index of coarse cognitive function in PD. We report two major results. First, in 82 PD patients we found significant relationships between lower intra-network connectivity of the frontoparietal network (FPN; comprising the dorsolateral prefrontal and posterior parietal cortices bilaterally) with lower MoCA scores. Second, we found significant relationships between lower inter-network connectivity between the SN and the basal ganglia network (BGN) and the default mode network (DMN) with lower MoCA scores. These data support our hypothesis about the SN and provide new insights into the brain networks contributing to cognitive impairments in PD.

Central precuneus lesions are associated with impaired executive function.

The functional roles of the precuneus are unclear. Focal precuneus lesions are rare, making it difficult to identify robust brain-behavior relationships. Distinct functional subdivisions of the precuneus have been proposed based on unique connectivity profiles. This includes an association of the anterior division with bodily awareness, the central region with complex cognition, and the posterior division with visual processing. Our goal was to test the hypothesis that the central precuneus is preferentially involved (compared to the other sectors of the precuneus) in executive function, as estimated from performance on the trail-making test (TMT). 35 patients with focal brain lesions involving the precuneus were included from the University of Iowa and Montpellier University. Multivariate lesion symptom mapping of TMT performance was performed to evaluate whether lesion location was associated with impaired task performance. Lesion symptom mapping revealed a statistically significant association of central precuneus lesions with impaired TMT performance (r = 0.43, p < 0.01). Further, a functional network derived from this precuneus region showed connectivity to other cortical areas implicated in executive function, including the dorsolateral prefrontal cortex and inferior parietal lobe. This analysis provides support for the role of the central precuneus in executive function, consistent with the unique connectivity pattern of the central precuneus with a broader network implicated in cognitive control and executive function.

Neuromodulation of cognition in Parkinson's disease.

Neuromodulation is a widely used treatment for motor symptoms of Parkinson's disease (PD). It can be a highly effective treatment as a result of knowledge of circuit dysfunction associated with motor symptoms in PD. However, the mechanisms underlying cognitive symptoms of PD are less well-known, and the effects of neuromodulation on these symptoms are less consistent. Nonetheless, neuromodulation provides a unique opportunity to modulate motor and cognitive circuits while minimizing off-target side effects. We review the modalities of neuromodulation used in PD and the potential implications for cognitive symptoms. There have been some encouraging findings with both invasive and noninvasive modalities of neuromodulation, and there are promising advances being made in the field of therapeutic neuromodulation. Substantial work is needed to determine which modulation targets are most effective for the different types of cognitive deficits of PD.

The Impact of Telemedicine on Pediatric Critical Care Triage.

OBJECTIVE: To examine the relationship between pediatric critical care telemedicine consultation to rural emergency departments and triage decisions. We compare the triage location and provider rating of the accuracy of remote assessment for a cohort of patients who receive critical care telemedicine consultations and a similar group of patients receiving telephone consultations. DESIGN: Retrospective evaluation of consultations occurring between April 2012 and March 2016. SETTING: Pediatric critical care telemedicine and telephone consultations in 52 rural healthcare settings in South Carolina. PATIENTS: Pediatric patients receiving critical care telemedicine or telephone consultations. INTERVENTION: Telemedicine consultations. MEASUREMENTS AND MAIN RESULTS: Data were collected from the consulting provider for 484 total consultations by telephone or telemedicine. We examined the providers' self-reported assessments about the consultation, decision-making, and triage outcomes. We estimate a logit model to predict triage location as a function of telemedicine consult age and sex. For telemedicine patients, the odds of triage to a non-ICU level of care are 2.55 times larger than the odds for patients receiving telephone consultations (p = 0.0005). Providers rated the accuracy of their assessments higher when consultations were provided via telemedicine. When patients were transferred to a non-ICU location following a telemedicine consultation, providers indicated that the use of telemedicine influenced the triage decision in 95.7% of cases (p < 0.001). For patients transferred to a non-ICU location, an increase in transfers to a higher level of care within 24 hours was not observed. CONCLUSION: Pediatric critical care telemedicine consultation to community hospitals is feasible and results in a reduction in PICU admissions. This study demonstrates an improvement in provider-reported accuracy of patient assessment via telemedicine compared with telephone, which may produce a higher comfort level with transporting patients to a lower level of care. Pediatric critical care telemedicine consultations represent a promising means of improving care and reducing costs for critically ill children in rural areas.