The use of cerebrospinal fluid and neuropathologic studies in neuropsychiatry practice and research

Tract-Specific Relationships Between Cerebrospinal Fluid Biomarkers and Periventricular White Matter in Posthemorrhagic Hydrocephalus of Prematurity

BACKGROUND

Posthemorrhagic hydrocephalus (PHH) is associated with neurological morbidity and complex neurosurgical care. Improved tools are needed to optimize treatments and to investigate the developmental sequelae of PHH.

OBJECTIVE

To examine the relationship between diffusion magnetic resonance imaging (dMRI) and cerebrospinal fluid (CSF) biomarkers of PHH.

METHODS

A total of 14 preterm (PT) infants with PHH and 46 controls were included. PT CSF was collected at temporizing surgery in PHH infants (PHH PT CSF) or lumbar puncture in controls. Term-equivalent age (TEA) CSF was acquired via implanted device or at permanent CSF diversion surgery in PHH (PHH-TEA-CSF) or lumbar puncture in controls. TEA dMRI scans were used to measure fractional anisotropy (FA) and mean diffusivity (MD) in the genu of corpus callosum (gCC), posterior limb of internal capsule (PLIC), and optic radiations (OPRA). Associations between dMRI measures and CSF amyloid precursor protein (APP), neural cell adhesion-1 (NCAM-1), and L1 cell adhesion molecule (L1CAM) were assessed using Pearson correlations.

RESULTS

APP, NCAM-1, and L1CAM were elevated over controls in PHH-PT-CSF and PHH-TEA-CSF. dMRI FA and MD differed between control and PHH infants across all tracts. PHH-PT-CSF APP levels correlated with gCC and OPRA FA and PLIC MD, while L1CAM correlated with gCC and OPRA FA. In PHH-TEA-CSF, only L1CAM correlated with OPRA MD.

CONCLUSION

Tract-specific associations were observed between dMRI and CSF biomarkers at the initiation of PHH treatment. dMRI and CSF biomarker analyses provide innovative complementary methods for examining PHH-related white matter injury and associated developmental sequelae.

Defining and predicting transdiagnostic categories of neurodegenerative disease

The prevalence of concomitant proteinopathies and heterogeneous clinical symptoms in neurodegenerative diseases hinders the identification of individuals who might be candidates for a particular intervention. Here, by applying an unsupervised clustering algorithm to post-mortem histopathological data from 895 patients with degeneration in the central nervous system, we show that six non-overlapping disease clusters can simultaneously account for tau neurofibrillary tangles, α-synuclein inclusions, neuritic plaques, inclusions of the transcriptional repressor TDP-43, angiopathy, neuron loss and gliosis. We also show that membership to the six transdiagnostic disease clusters, which explains more variance in cognitive phenotypes than can be explained by individual diagnoses, can be accurately predicted from scores of the Mini-Mental Status Exam, protein levels in cerebrospinal fluid, and genotype at the APOE and MAPT loci, via cross-validated multiple logistic regression. This combination of unsupervised and supervised data-driven tools provides a framework that could be used to identify latent disease subtypes in other areas of medicine.

Implantable Sensor for Detecting Changes in the Loss Tangent of Cerebrospinal Fluid

The increasing utilization of cerebrospinal fluid (CSF) in early detection of Alzheimer's disease (AD) is attributed to the change of Amyloid- β proteins. Since, the brain is suspended in CSF, changes of Amyloid- β proteins in CSF reflect a pathophysiological variation of the brain due to AD. However, the correlation between Amyloid- β proteins and the dielectric properties (DPs) of CSF is still an open question. This paper reports the characterized DPs of CSF collected from canines using lumbar punctures. The CSF samples from canines show a strong correlation with respect to human in terms of the loss tangent, which indicates suitability of using canines as translational primates. Amyloid- β [ Aβ(1-40) and Aβ(1-42)] proteins associated with AD were added to CSF samples in order to emulate AD condition. The results of emulated AD condition suggest a decrease in the relative permittivity and increase in the loss tangent. To detect changes in the loss tangent of CSF, which combines both relative permittivity and conductivity, a developed sensor is proposed. The designed sensor consists of a voltage controlled oscillator (VCO) and implantable antenna, which exhibits a wideband and low quality factor to be stable with respect to changes in the loss tangent of CSF. The measurements of the received power levels from the sensor in different liquid-based phantoms having different loss tangent values were used to correlate changes in the loss tangent. The developed correlation model is able to predict the loss tangent based on the received power level, which can be used to detect changes in the loss tangent of CSF due to AD. Consequently, this approach could be used as an early diagnosis of AD.

The Mental Status Examination in Patients With Suspected Dementia

PURPOSE OF REVIEW

This article describes a comprehensive approach to the mental status examination and diagnostic workup of patients suspected of having an emerging neurodegenerative dementia. Key strategies for obtaining a history and bedside examination techniques are highlighted.

RECENT FINDINGS

Classic descriptions of behavioral neurology syndromes were largely based on clinicopathologic correlations of strategic lesions in stroke patients. While still very important, advances in neuroimaging have expanded our armamentarium of cognitive evaluations to include assessments of findings in nonstroke anatomic distributions of disease. These efforts support comprehensive assessments of large-scale cerebral networks in cognitive neurology.

SUMMARY

A thorough and focused mental status examination is essential for the evaluation of patients with cognitive symptoms. Selective use of laboratory testing and neuroimaging can aid in the diagnosis of dementia by excluding non-neurodegenerative etiologies. Neurodegenerative disease-specific tests are in development and will enhance diagnosis and efforts for disease-modifying therapy development.