Evaluation of a prototype point-of-care instrument based on monochromatic x-ray fluorescence spectrometry: potential for monitoring trace element status of subjects with neurodegenerative disease.

Assessment of trace elements such as Cu, Zn, and Se in patients with neurodegenerative disease, such as Alzheimer's (AD) and Parkinson's disease (PD), may be useful in etiologic studies and in assessing the risk of developing these conditions. A prototype point-of-care (POC) instrument based on monochromatic x-ray fluorescence (M-XRF) was assembled and evaluated for the determination of Cu, Zn, and Se in whole blood, plasma, and urine. The prototype instrument was validated using certified reference materials for Cu and Zn in serum/plasma, and the reported bias and relative imprecision were <10%. The M-XRF prototype performance was further assessed using human specimens collected from AD and PD subjects, and was found to be satisfactory (<20% bias) for monitoring Cu and Zn levels in plasma and whole blood. However, the prototype M-XRF sensitivity was not sufficient for quantifying Cu, Zn, or Se in urine. Nonetheless, while validating the prototype instrument, body fluids (whole blood, plasma, and urine) were collected from 19 AD patients, 23 PD patients, and 24 controls specifically for trace element analysis using well-validated methods based on inductively coupled plasma mass spectrometry (ICP-MS). This limited biomonitoring study provided robust data for up to 16 elements including Sb, As, Ba, Cd, Cs, Co, Cr, Cu, Hg, Pb, Mo, Se, Tl, Sn, Zn, and U in plasma, whole blood, and urine. The results did not indicate any significant differences in most trace elements studied between AD or PD patients compared to controls, although the sample size is limited. A statistically significant increase in plasma Se was identified for PD patients relative to AD patients, but this could be due to age differences.

Improved myo-inositol detection through Carr-Purcell PRESS: a tool for more sensitive mild cognitive impairment diagnosis.

A 3-T study is presented, comparing the ability of two (1) H spectroscopy pulse sequences, Carr-Purcell point resolved spectroscopy (CPRESS; TE = 45 msec), and conventional PRESS (TE = 35 msec), to separate between groups of 20 normal control (NC) and 20 mild cognitive impairment (MCI) subjects. Both sequences showed higher myo-inositol (mI) and mI/N-acetyl-aspartate (NAA) levels in the posterior cingulate gyrus of the MCI subjects. The increased intrasubject repeatability of mI and mI/NAA CPRESS measurements (∼ 6% vs. 9% for PRESS) translated into decreased intraclass variability. A 22% intraclass mI PRESS variability was reduced to 16% for CPRESS, and an 18% intraclass mI/NAA PRESS variability was reduced to 12% for CPRESS for the group of NC subjects. Similar results were observed for the MCI subjects. Decreased intraclass variability led to improved separation between NC and MCI subjects (P = 0.017 for PRESS and P < 0.0001 for CPRESS mI/NAA, the best NC/MCI discriminant for each method). Seventy-five percent sensitivity at eighty percent specificity was demonstrated by mI/NAA CPRESS measurements in separating NC from MCI subjects. High correlations were also observed between subject performance on a number of neuropsychological tests (probing verbal memory, visuoconstruction performance, and visual motor integration) and the mI/NAA ratio; higher correlation coefficients (with stronger statistical significance) were consistently evident for CPRESS than for PRESS data.

Raman spectroscopy and machine learning for biomedical applications: Alzheimer's disease diagnosis based on the analysis of cerebrospinal fluid.

Current Alzheimer's disease (AD) diagnostics is based on clinical assessments, imaging and neuropsychological tests that are efficient only at advanced stages of the disease. Early diagnosis of AD will provide decisive opportunities for preventive treatment and development of disease-modifying drugs. Cerebrospinal fluid (CSF) is in direct contact with the human brain, where the deadly pathological process of the disease occurs. As such, the CSF biochemical composition reflects specific changes associated with the disease and is therefore the most promising body fluid for AD diagnostic test development. Here, we describe a new method to diagnose AD based on CSF via near infrared (NIR) Raman spectroscopy in combination with machine learning analysis. Raman spectroscopy is capable of probing the entire biochemical composition of a biological fluid at once. It has great potential to detect small changes specific to AD, even at the earliest stages of pathogenesis. NIR Raman spectra were measured of CSF samples acquired from 21 patients diagnosed with AD and 16 healthy control (HC) subjects. Artificial neural networks (ANN) and support vector machine discriminant analysis (SVM-DA) statistical methods were used for differentiation purposes, with the most successful results allowing for the differentiation of AD and HC subjects with 84% sensitivity and specificity. Our classification models show high discriminative power, suggesting the method has a great potential for AD diagnostics. The reported Raman spectroscopic examination of CSF can complement current clinical tests, making early AD detection fast, accurate, and inexpensive. While this study shows promise using a small sample set, further method validation on a larger scale is required to indicate the true strength of the approach.

Magnetic field correlation as a measure of iron-generated magnetic field inhomogeneities in the brain.

The magnetic field correlation (MFC) at an applied field level of 3 Tesla was estimated by means of MRI in several brain regions for 21 healthy human adults and 1 subject with aceruloplasminemia. For healthy subjects, highly elevated MFC values compared with surrounding tissues were found within the basal ganglia. These are argued as being primarily the result of microscopic magnetic field inhomogeneities generated by nonheme brain iron. The MFC in the aceruloplasminemia subject was significantly higher than for healthy adults in the globus pallidus, thalamus and frontal white matter, consistent with the known increased brain iron concentration associated with this disease.

The Aerobic and Cognitive Exercise Study (ACES) for Community-Dwelling Older Adults With or At-Risk for Mild Cognitive Impairment (MCI): Neuropsychological, Neurobiological and Neuroimaging Outcomes of a Randomized Clinical Trial.

Prior research has found that cognitive benefits of physical exercise and brain health in older adults may be enhanced when mental exercise is interactive simultaneously, as in exergaming. It is unclear whether the cognitive benefit can be maximized by increasing the degree of mental challenge during exercise. This randomized clinical trial (RCT), the Aerobic and Cognitive Exercise Study (ACES) sought to replicate and extend prior findings of added cognitive benefit from exergaming to those with or at risk for mild cognitive impairment (MCI). ACES compares the effects of 6 months of an exer-tour (virtual reality bike rides) with the effects of a more effortful exer-score (pedaling through a videogame to score points). Fourteen community-dwelling older adults meeting screening criteria for MCI (sMCI) were adherent to their assigned exercise for 6 months. The primary outcome was executive function, while secondary outcomes included memory and everyday cognitive function. Exer-tour and exer-score yielded significant moderate effects on executive function (Stroop A/C; d's = 0.51 and 0.47); there was no significant interaction effect. However, after 3 months the exer-tour revealed a significant and moderate effect, while exer-score showed little impact, as did a game-only condition. Both exer-tour and exer-score conditions also resulted in significant improvements in verbal memory. Effects appear to generalize to self-reported everyday cognitive function. Pilot data, including salivary biomarkers and structural MRI, were gathered at baseline and 6 months; exercise dose was associated with increased BDNF as well as increased gray matter volume in the PFC and ACC. Improvement in memory was associated with an increase in the DLPFC. Improved executive function was associated with increased expression of exosomal miRNA-9. Interactive physical and cognitive exercise (both high and low mental challenge) yielded similarly significant cognitive benefit for adherent sMCI exercisers over 6 months. A larger RCT is needed to confirm these findings. Further innovation and clinical trial data are needed to develop accessible, yet engaging and effective interventions to combat cognitive decline for the growing MCI population. ClinicalTrials.gov ID: NCT02237560.

High-field magnetic resonance imaging of brain iron in Alzheimer disease.

OBJECTIVES: Increased iron deposition in the brain may occur in several neurodegenerative diseases, including Alzheimer disease (AD). Iron deposits shorten T2 relaxation times on T2-weighted magnetic resonance (MR) images. Iron-dependent contrast increases with magnetic field strength. We hypothesized that T2 mapping using 3 T MR imaging (MRI) can disclose differences between normal controls and AD subjects. METHODS: High-resolution brain imaging protocols were developed and applied to 24 AD patients and 20 age-matched controls using 3 T MRI. Eight anatomical regions of interest were manually segmented, and T2 histograms were computed. A visual analysis technique, the heat map, was modified and applied to the large image data sets generated by these protocols. RESULTS: A large number (163) of features from these histograms were examined, and 38 of these were significantly different (P < 0.05) between the groups. In the hippocampus, evidence was found for AD-related increases in iron deposition (shortened T2) and in the concentration of free tissue water (lengthened T2). Imaging of a section of postmortem brain before and after chemically extracting the iron established the presence of MRI-detectable iron in the hippocampus, cortex, and white matter in addition to brain regions traditionally viewed as containing high iron concentrations.

Macular degeneration in a patient with aceruloplasminemia, a disease associated with retinal iron overload.

PURPOSE: To provide the first ophthalmic case report of a Caucasian patient with the rare autosomal recessive disease aceruloplasminemia, which results in iron overload in the retina, brain, and pancreas. DESIGN: Single observational case report. METHODS: Perls' staining of a conjunctival biopsy was used to detect elevated iron levels in the conjunctival epithelium. Fundus photography, fluorescein angiography, and electroretinography were used to document retinal appearance and function. RESULTS: Unlike a report of a Japanese patient with aceruloplasminemia, who had midperipheral retinal pigment epithelium (RPE) cell atrophy and yellowish discoloration of the fundus, our Caucasian patient had a maculopathy. Beginning at age 47, he had development and progression of multiple subretinal yellowish-white lesions and RPE cell atrophy. To confirm tissue iron overload in our patient, we took the novel approach of a conjunctival biopsy, which showed Perls' Prussian blue-positive epithelial cells. CONCLUSIONS: Given our recent finding of elevated iron levels in the RPE of patients with age-related macular degeneration (AMD), it is interesting that retinal iron overload in aceruloplasminemia is associated with a maculopathy that clinically resembles AMD. This finding supports the hypothesis that retinal iron homeostasis is essential for normal retinal function. Disruption of iron homeostasis could contribute to the pathogenesis of AMD.

Anti-Ri-associated paraneoplastic brainstem cerebellar syndrome with coexisting limbic encephalitis in a patient with mixed large cell neuroendocrine lung carcinoma.

Paraneoplastic neurologic syndromes (PNS) can be the first manifestations of occult malignancies. If left untreated, PNS often lead to significant morbidity and mortality. Anti-Ri (anti-neuronal nuclear antibody type 2 [ANNA-2]) autoantibodies are commonly associated with breast and small cell lung cancers. Cases of anti-Ri paraneoplastic cerebellar degeneration are reported, but few describe severe nausea and coexisting limbic encephalitis as the major presenting features. We report a 75-year-old woman with medically-intractable emesis, encephalopathy, diplopia, vertigo, and gait ataxia for 3 months. Examination revealed rotary nystagmus, ocular skew deviation, limb dysmetria, and gait ataxia. After two courses of intravenous immunoglobulin, there was minimal improvement. Anti-Ri antibodies were positive in serum only. CT scan identified a 2.0 cm left lung mass, and histopathology revealed large cell neuroendocrine carcinoma with admixed adenocarcinoma non-small cell lung carcinoma (NCSLC). Though the patient achieved nearly complete clinical recovery after tumor resection, anti-Ri levels remained high at 20 months post-resection. To our knowledge this is the first report of a paraneoplastic brainstem cerebellar syndrome with coexisting limbic encephalitis involving anti-Ri positivity and associated mixed neuroendocrine/NSCLC of the lung with marked improvement after tumor resection.

Raman spectroscopy of blood serum for Alzheimer's disease diagnostics: specificity relative to other types of dementia.

The key moment for efficiently and accurately diagnosing dementia occurs during the early stages. This is particularly true for Alzheimer's disease (AD). In this proof-of-concept study, we applied near infrared (NIR) Raman microspectroscopy of blood serum together with advanced multivariate statistics for the selective identification of AD. We analyzed data from 20 AD patients, 18 patients with other neurodegenerative dementias (OD) and 10 healthy control (HC) subjects. NIR Raman microspectroscopy differentiated patients with more than 95% sensitivity and specificity. We demonstrated the high discriminative power of artificial neural network (ANN) classification models, thus revealing the high potential of this developed methodology for the differential diagnosis of AD. Raman spectroscopic, blood-based tests may aid clinical assessments for the effective and accurate differential diagnosis of AD, decrease the labor, time and cost of diagnosis, and be useful for screening patient populations for AD development and progression. Multivariate data analysis of blood serum Raman spectra allows for the differentiation between patients with Alzheimer's disease, other types of dementia and healthy individuals.

Polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and neuropsychological status among older adults in New York.

Polybrominated diphenyl ethers (PBDEs) are emerging environmental contaminants, but little is known about their possible human health effects. The objective of this study is to evaluate the association between exposure to PBDEs and neuropsychological function among older adults and the possibility of effect modification with polychlorinated biphenyls (PCBs). Serum samples were analyzed for concentrations of 9 PBDE and 30 PCB congeners and 34 tests of cognitive and motor function, affective state, and olfactory function were assessed among 144 men and women of 55-74 years of age. After adjustment for relevant confounders, no overall associations were observed between the sum of the PBDE congener concentrations in serum (∑ PBDE) and scores on the neuropsychological tests. However, statistically significant interactions were found between PBDEs and PCBs for some measures of verbal learning and memory. Among persons with ∑ PCB concentrations at or above the median of 467ppb (lipid basis), an increase in ∑ PBDE concentrations from the 25th to 75th percentile was associated with decreases between 7% and 12% on scores for certain subscales of the California Verbal Learning Test. In contrast, no statistically significant associations were observed for PBDEs among persons with ∑ PCB levels below the median. The results suggest that PBDEs and PCBs may interact to affect verbal memory and learning among persons 55-74 years old. This is the first study to evaluate the neuropsychological effects of PBDEs in adults and the possibility of synergy with PCBs in humans.

Exergaming and older adult cognition: a cluster randomized clinical trial.

BACKGROUND: Dementia cases may reach 100 million by 2050. Interventions are sought to curb or prevent cognitive decline. Exercise yields cognitive benefits, but few older adults exercise. Virtual reality-enhanced exercise or "exergames" may elicit greater participation. PURPOSE: To test the following hypotheses: (1) stationary cycling with virtual reality tours ("cybercycle") will enhance executive function and clinical status more than traditional exercise; (2) exercise effort will explain improvement; and (3) brain-derived neurotrophic growth factor (BDNF) will increase. DESIGN: Multi-site cluster randomized clinical trial (RCT) of the impact of 3 months of cybercycling versus traditional exercise, on cognitive function in older adults. Data were collected in 2008-2010; analyses were conducted in 2010-2011. SETTING/PARTICIPANTS: 102 older adults from eight retirement communities enrolled; 79 were randomized and 63 completed. INTERVENTIONS: A recumbent stationary ergometer was utilized; virtual reality tours and competitors were enabled on the cybercycle. MAIN OUTCOME MEASURES: Executive function (Color Trails Difference, Stroop C, Digits Backward); clinical status (mild cognitive impairment; MCI); exercise effort/fitness; and plasma BDNF. RESULTS: Intent-to-treat analyses, controlling for age, education, and cluster randomization, revealed a significant group X time interaction for composite executive function (p=0.002). Cybercycling yielded a medium effect over traditional exercise (d=0.50). Cybercyclists had a 23% relative risk reduction in clinical progression to MCI. Exercise effort and fitness were comparable, suggesting another underlying mechanism. A significant group X time interaction for BDNF (p=0.05) indicated enhanced neuroplasticity among cybercyclists. CONCLUSIONS: Cybercycling older adults achieved better cognitive function than traditional exercisers, for the same effort, suggesting that simultaneous cognitive and physical exercise has greater potential for preventing cognitive decline. TRIAL REGISTRATION: This study is registered at Clinicaltrials.gov NCT01167400.

Subclinical zinc deficiency in Alzheimer's disease and Parkinson's disease.

To evaluate zinc status in Alzheimer's disease and Parkinson's disease, 29 patients with Alzheimer's disease, 30 patients with Parkinson's disease, and 29 age- and sex-matched controls were studied. All patients and controls were older than age 50, and all zinc and copper supplements were prohibited beginning 30 days prior to study. Patients were diagnosed by standard criteria. Blood zinc and urine zinc were measured. Urine zinc was measured in a casual specimen, standardized for dilution by reference to creatinine content. Results showed a significantly lower blood zinc in patients with Alzheimer's and patients with Parkinson's than in controls. Urine zinc excretion, normalized to urine creatinine excretion, was not significantly different in either patient group compared to controls. These patients are probably zinc deficient because of nutritional inadequacy.

Copper and ceruloplasmin abnormalities in Alzheimer's disease.

The idea that copper may play a role in the pathogenesis of Alzheimer's disease is gaining momentum. Serum copper and ceruloplasmin were measured by both enzymatic (eCp) and immunologic (iCp) methods in 28 patients with Alzheimer's disease and 29 age-matched controls. ''Free copper'' was determined by subtracting copper accounted for in the eCp assay from total serum copper. Percentage free copper, that is the proportion of serum copper not bound to ceruloplasmin, was significantly elevated in patients with Alzheimer's compared to controls. There was significantly more ''defective'' ceruloplasmin, which is apoceruloplamin lacking its copper, in Alzheimer's disease than in normal controls. This abnormality may precede the clinical onset of the disease and help predict risk of disease onset. Increased exposure to environmental copper (eg, the spread of copper plumbing and the use of copper in supplements) and/or defective ceruloplasmin function may play a role in the current epidemic of Alzheimer's disease.

Iron accumulation in the substantia nigra of patients with Alzheimer disease and parkinsonism.

BACKGROUND: Preliminary studies have shown an increase in iron accumulation in the substantia nigra but not in the hippocampus in patients with Parkinson disease without dementia and the reverse in patients with Alzheimer disease (AD) and no parkinsonism. OBJECTIVE: To determine whether iron levels (measured as T2 shortening on magnetic resonance images) are greater in the substantia nigra of patients with AD who have parkinsonism than in those with AD alone. DESIGN: Case-control study. SETTING: Albany Medical College, Albany, New York. PARTICIPANTS: Fifteen patients with only AD (controls) and 18 with AD as well as parkinsonism, aged 56 to 89 years, and with a total Clinical Dementia Rating of 5.0 to 11.5. Patients were selected according to the purity of their disease; patients with a Unified Parkinson's Disease Rating Scale motor score of 15 or greater were considered to have parkinsonism. Main Outcome Measure Area under the curve for short T2 (30 milliseconds) in patients with only AD vs patients with AD who developed parkinsonism. RESULTS: Patients who developed parkinsonism along with their existing dementia had significantly more iron in their substantia nigra than did patients with AD alone (P = .03, 2-sample t test). CONCLUSIONS: Iron accumulation may be a predictor of parkinsonism. The development of parkinsonism during the course of AD appears to be associated with the accumulation of iron, which in turn may contribute to the pathogenesis of neurologic decline.

Clinical and pathological continuum of multisystem TDP-43 proteinopathies.

OBJECTIVE: To determine the extent of transactivation response DNA-binding protein with a molecular weight of 43 kDa (TDP-43) pathology in the central nervous system of patients with clinically and autopsy-confirmed diagnoses of frontotemporal lobar degeneration with and without motor neuron disease and amyotrophic lateral sclerosis with and without cognitive impairment. DESIGN: Performance of immunohistochemical whole-central nervous system scans for evidence of pathological TDP-43 and retrospective clinical medical record review. SETTING: An academic medical center. PARTICIPANTS: We included 64 patients with clinically and pathologically confirmed frontotemporal lobar degeneration with ubiquitinated inclusions with or without motor neuron disease and amyotrophic lateral sclerosis with or without cognitive impairment. MAIN OUTCOME MEASURE: Neuronal and glial TDP-43 pathology. RESULTS: We found evidence of neuronal and glial TDP-43 pathology in all disease groups throughout the neuraxis, albeit with variations in the frequency, morphology, and distribution of TDP-43 lesions. Moreover, the major clinical manifestations (eg, cognitive impairments, motor neuron signs, extrapyramidal symptoms, neuropsychiatric features) were reflected by the predominant distribution and burden of TDP-43 pathology. CONCLUSION: These findings strongly suggest that amyotrophic lateral sclerosis, frontotemporal lobar degeneration with amyotrophic lateral sclerosis or motor neuron disease, and frontotemporal lobar degeneration with ubiquitinated inclusions are different manifestations of a multiple-system TDP-43 proteinopathy linked to similar mechanisms of neurodegeneration.

1H MR spectroscopy using TE averaged PRESS: a more sensitive technique to detect neurodegeneration associated with Alzheimer's disease.

A sensitive proton magnetic resonance spectroscopy ((1)H MRS) acquisition scheme that is capable of discriminating between normal controls and a group of patients with early Alzheimer's disease (AD) is presented. The performance of this newly developed method, TE averaged PRESS (PRESS-J), in detecting neurodegeneration associated with early AD is compared with that of short echo time (TE) PRESS. A stepwise discriminant function analysis is used to construct discriminant functions for both pulse sequences. These functions are each composed of a single predictor: the N-acetyl aspartate (NAA)/creatine (Cr) ratio for PRESS-J, and the NAA/myoInositol (mI) ratio for PRESS. We observed lower P-values, higher areas under the receiver operating characteristic curves, and higher sensitivity at a given specificity for the PRESS-J discriminating function in comparison with the PRESS discriminating function. The higher sensitivity of PRESS-J is due to decreased variability when the singlets are fit in the spectra. This increased sensitivity enables new MR applications and, among other benefits, allows for smaller group sizes in drug trials, which can significantly reduce the cost of such trials.

High-field magnetic resonance imaging of brain iron: birth of a biomarker?

The brain has an unusually high concentration of iron, which is distributed in an unusual pattern unlike that in any other organ. The physiological role of this iron and the reasons for this pattern of distribution are not yet understood. There is increasing evidence that several neurodegenerative diseases are associated with altered brain iron metabolism. Understanding these dysmetabolic conditions may provide important information for their diagnosis and treatment. For many years the iron distribution in the human brain could be studied effectively only under postmortem conditions. This situation was changed dramatically by the finding that T2-weighted MR imaging at high field strength (initially 1.5 T) appears to demonstrate the pattern of iron distribution in normal brains and that this imaging technique can detect changes in brain iron concentrations associated with disease states. Up to the present time this imaging capability has been utilized in many research applications but it has not yet been widely applied in the routine diagnosis and management of neurodegenerative disorders. However, recent advances in the basic science of brain iron metabolism, the clinical understanding of neurodegenerative diseases and in MRI technology, particularly in the availability of clinical scanners operating at the higher field strength of 3 T, suggest that iron-dependent MR imaging may soon provide biomarkers capable of characterizing the presence and progression of important neurological disorders. Such biomarkers may be of crucial assistance in the development and utilization of effective new therapies for Alzheimer's and Parkinson's diseases, multiple sclerosis and other iron-related CNS disorders which are difficult to diagnose and treat.