Directed functional connectivity of the default-mode-network of young and older healthy subjects

Alterations in the default mode network (DMN) are associated with aging. We assessed age-dependent changes of DMN interactions and correlations with a battery of neuropsychological tests, to understand the differences of DMN directed connectivity between young and older subjects. Using a novel multivariate analysis method on resting-state functional MRI data from fifty young and thirty-one healthy older subjects, we calculated intra- and inter-DMN 4-nodes directed pathways. For the old subject group, we calculated the partial correlations of inter-DMN pathways with: psychomotor speed and working memory, executive function, language, long-term memory and visuospatial function. Pathways connecting the DMN with visual and limbic regions in older subjects engaged at BOLD low frequency and involved the dorsal posterior cingulate cortex (PCC), whereas in young subjects, they were at high frequency and involved the ventral PCC. Pathways combining the sensorimotor (SM) cortex and the DMN, were SM efferent in the young subjects and SM afferent in the older subjects. Most DMN efferent pathways correlated with reduced speed and working memory. We suggest that the reduced sensorimotor efferent and the increased need to control such activities, cause a higher dependency on external versus internal cues thus suggesting how physical activity might slow aging.

Normative Data for the Judgment of Line Orientation Test (Long and Short Forms) in the Quebec-French Population Aged between 50 and 89 Years

The Judgment of Line Orientation (JLO) Test of Benton assesses visuospatial processing without requiring motor skills. The test is frequently used in geriatric or brain-injured populations. As with other cognitive tests, performance on the JLO test may vary according to age, level of education, sex, and cultural background of individuals. The present study aimed to establish normative data for a short (15 items) and a long (30 items) form of the JLO. The sample for the short and long forms comprised 198 and 260 individuals, respectively, aged 50-89 years. All participants were French-speaking people from the province of Quebec, Canada. Using regression-based norming, the effects of age, years of formal education, and sex on JLO performance were estimated. The normative adjustment of the JLO short and long forms considered the weight of each predictor on test performance. Results indicated that JLO performance was positively associated with years of formal education and male sex, whereas it was negatively associated with age. Accordingly, normative data were generated using Z-scores and adjusted scaled scores derived from the regression equations. To conclude, the present norms will ease the detection of visuospatial impairment in French-Quebec middle-aged and older adults.

Diagnostic Precision in the Detection of Mild Cognitive Impairment: A Comparison of Two Approaches

OBJECTIVE

This study compared diagnostic rates and clinical predictors of discrepancies between diagnoses conferred via: 1) a comprehensive neuropsychological evaluation and National Institute on Aging-Alzheimer's Association (NIA-AA) criteria versus 2) a cognitive screener and Diagnostic Statistical Manual of Mental Disorders (DSM-5) criteria.

DESIGN

Cross-sectional examination of baseline data from the Prevention of Alzheimer's dementia (AD) using Cognitive remediation and transcranial direct current stimulation in Mild Cognitive Impairment (MCI) and Depression (PACt-MD; ClinicalTrials.gov Identifier: NCT02386670) trial.

SETTING

Five geriatric psychiatry and memory clinics located at academic hospitals affiliated with the Department of Psychiatry, University of Toronto.

PARTICIPANTS

Older adults (N = 431) with a history of major depressive disorder (MDD) in remission, MCI, or both.

MEASUREMENTS

Main outcome was a comparison of NIA-AA diagnostic rates of MCI or dementia versus DSM-5 rates of mild or major neurocognitive disorder. Secondary analyses examined demographic, race, gender, premorbid intellectual ability, psychosocial, health-related, and genetic predictors of discrepancy between DSM-5 and NIA-AA diagnoses.

RESULTS

There were 103 (23.8%) discrepant cases, with most (91; 88.3%) of these discrepant cases reflecting more impairment with the detailed neuropsychological testing and NIA-AA criteria. Discrepancies were more likely in individuals with a history of MDD or who had at least one ApoE4 allele.

CONCLUSION

The NIA-AA criteria, in conjunction with comprehensive neuropsychological testing, identified a greater prevalence of cognitive impairment than DSM-5 criteria, in conjunction with the Montreal Cognitive Assessment. Detailed neuropsychological evaluations are recommended for older adults who have a history of MDD or a genetic vulnerability to dementia.

Neuropsychological assessment could distinguish among different clinical phenotypes of progressive supranuclear palsy: A Machine Learning approach

Progressive supranuclear palsy (PSP) is a rare, rapidly progressive neurodegenerative disease. Richardson's syndrome (PSP-RS) and predominant parkinsonism (PSP-P) are characterized by wide range of cognitive and behavioural disturbances, but these variants show similar cognitive pattern of alterations, leading difficult differential diagnosis. For this reason, we explored with an Artificial Intelligence approach, whether cognitive impairment could differentiate the phenotypes. Forty Parkinson's disease (PD) patients, 25 PSP-P, 40 PSP-RS, and 34 controls were enrolled following the consensus criteria diagnosis. Participants were evaluated with neuropsychological battery for cognitive domains. Random Forest models were used for exploring the discriminant power of the cognitive tests in distinguishing among the four groups. The classifiers for distinguishing diseases from controls reached high accuracies (86% for PD, 95% for PSP-P, 99% for PSP-RS). Regarding the differential diagnosis, PD was discriminated from PSP-P with 91% (important variables: HAMA, MMSE, JLO, RAVLT_I, BDI-II) and from PSP-RS with 92% (important variables: COWAT, JLO, FAB). PSP-P was distinguished from PSP-RS with 84% (important variables: JLO, WCFST, RAVLT_I, Digit span_F). This study revealed that PSP-P, PSP-RS and PD had peculiar cognitive deficits compared with healthy subjects, from which they were discriminated with optimal accuracies. Moreover, high accuracies were reached also in differential diagnosis. Most importantly, Machine Learning resulted to be useful to the clinical neuropsychologist in choosing the most appropriate neuropsychological tests for the cognitive evaluation of PSP patients.

Impact of dopamine and cognitive impairment on neural reactivity to facial emotion in Parkinson's disease

Emotional and cognitive impairments in Parkinson's disease (PD) are prevalent, hamper interpersonal relations and reduce quality of life. It is however unclear to what extent these domains interplay in PD-related deficits and how they are influenced by dopaminergic availability. This study examined the effect of cognitive impairment and dopaminergic medication on neural and behavioral mechanisms of facial emotion recognition in PD patients. PD patients on and off dopaminergic medication and matched healthy controls underwent an emotional face matching task during functional MRI. In addition, a comprehensive neuropsychological evaluation of cognitive function was conducted. Increased BOLD response to emotional faces was found in the visual cortex of PD patients relative to controls irrespective of cognitive function and medication status. Administration of dopaminergic medication in PD patients resulted in restored behavioral accuracy for emotional faces relative to controls and decreased retrosplenial cortex BOLD response to emotion relative to off-medication state. Furthermore, cognitive impairment in PD patients was associated with reduced behavioral accuracy for non-emotional stimuli and predicted BOLD response to emotion in the anterior and posterior cingulate cortices, depending on medication status. Findings of aberrant visual and retrosplenial BOLD response to emotion are suggested to stem from altered attentional and/or emotion-driven modulation from subcortical and higher cortical regions. Our results indicate neural disruptions and behavioral deficits in emotion processing in PD patients that are dependent on dopaminergic availability and independent of cognitive function. Our findings highlight the importance of dopaminergic treatment not only for the motor symptoms but also the emotional disturbances in PD.

Influence of sex differences in interpreting learning and memory within a clinical sample of older adults

Sex is an important factor to consider when evaluating memory with older adults. This present study aimed to examine sex differences in memory within a clinical sample of older adults (N = 1084). Raw learning and recall scores on the Hopkins Verbal Learning Test, Revised (HVLT-R) and Brief Visuospatial Memory Test, Revised (BVMT-R) were compared between sexes within the entire sample and cohorts stratified by age. Within the entire sample, women outperformed men in HVLT-R learning and recall, and there were no sex differences in BVMT-R performance. These sex differences, however, were absent or reversed for those with impaired HVLT-R performance and functional deficits, indicating that women retain an early advantage in verbal memory, which is lost with greater indication of disease severity. These findings indicate that women retain an advantage in verbal learning and memory, at least before significant levels of impairment, within a sample of older adults seen at an outpatient neurology clinic, which may have implications for diagnosing memory disorders.

Benton Judgment of Line Orientation (JoLO) Test: A Brief and Useful Measure for Assessing Visuospatial Abilities in Manifest, but not Premanifest, Huntington's Disease

BACKGROUND

Visuospatial deficits have been described in Huntington's disease (HD); however, the extent of these deficits remains unclear. The Benton Judgment of Line Orientation (JoLO) Test, commonly used to assess visuospatial ability, requires minimal motor involvement. It has demonstrated sensitivity to visuospatial deficits in Parkinson's disease; however, few studies have examined performance on this test in HD.

OBJECTIVE

The objective of the current study was to assess visuospatial ability in premanifest and manifest HD using the JoLO.

METHODS

A global cognitive measure, the Mattis Dementia Rating Scale (DRS), was used to stratify manifest HD patients as mild (DRS ≥129) vs. moderate-severe (DRS ≤128). Fifty mild, 42 moderate-severe, and 30 premanifest HD subjects, as well as 35 matched controls, were administered the JoLO. HD Burden of Pathology (BOP) scores were used as a measure of disease severity.

RESULTS

Results revealed that the total manifest HD sample (p <  0.001), in addition to the mild (p = 0.028), and moderate-severe (p <  0.001), but not premanifest, HD subjects scored significantly lower on the JoLO compared to normal controls.

CONCLUSIONS

Our results suggest that the JoLO is useful for detecting visuospatial deficits across various stages of manifest HD. However, any visuospatial impairment that might be present during the premanifest stage of HD was not detected using the JoLO in the present sample.

Dose-dense temozolomide for newly diagnosed glioblastoma: a randomized phase III clinical trial

PURPOSE

Radiotherapy with concomitant and adjuvant temozolomide is the standard of care for newly diagnosed glioblastoma (GBM). O(6)-methylguanine-DNA methyltransferase (MGMT) methylation status may be an important determinant of treatment response. Dose-dense (DD) temozolomide results in prolonged depletion of MGMT in blood mononuclear cells and possibly in tumor. This trial tested whether DD temozolomide improves overall survival (OS) or progression-free survival (PFS) in patients with newly diagnosed GBM.

PATIENTS AND METHODS

This phase III trial enrolled patients older than age 18 years with a Karnofsky performance score of ≥ 60 with adequate tissue. Stratification included clinical factors and tumor MGMT methylation status. Patients were randomly assigned to standard temozolomide (arm 1) or DD temozolomide (arm 2) for 6 to 12 cycles. The primary end point was OS. Secondary analyses evaluated the impact of MGMT status.

RESULTS

A total of 833 patients were randomly assigned to either arm 1 or arm 2 (1,173 registered). No statistically significant difference was observed between arms for median OS (16.6 v 14.9 months, respectively; hazard ratio [HR], 1.03; P = .63) or median PFS (5.5 v 6.7 months; HR, 0.87; P = .06). Efficacy did not differ by methylation status. MGMT methylation was associated with improved OS (21.2 v 14 months; HR, 1.74; P < .001), PFS (8.7 v 5.7 months; HR, 1.63; P < .001), and response (P = .012). There was increased grade ≥ 3 toxicity in arm 2 (34% v 53%; P < .001), mostly lymphopenia and fatigue.

CONCLUSION

This study did not demonstrate improved efficacy for DD temozolomide for newly diagnosed GBM, regardless of methylation status. However, it did confirm the prognostic significance of MGMT methylation. Feasibility of large-scale accrual, prospective tumor collection, and molecular stratification was demonstrated.

Gaucher disease ascertained through a Parkinson's center: imaging and clinical characterization

Among the genes implicated for parkinsonism is glucocerebrosidase (GBA), which causes Gaucher disease (GD). Despite a growing literature that GD may present as parkinsonism, neuroimaging, olfaction, and neuropsychological testing have not been extensively reported. We describe transcranial sonography (TCS), 18F-fluorodopa (F-dopa) and fluorodeoxyglucose (FDG) Positron emission tomography, olfaction testing, neuropsychological testing, and clinical features in homozygous and compound heterozygous GBA mutation carriers identified through screening of 250 Ashkenazi Jewish parkinsonian individuals treated at a tertiary care center. We identified two individuals with N370S/R496H compound heterozygous mutations and two with N370S homozygous mutations; one individual died before completing detailed evaluation. TCS (n = 3) demonstrated nigral hyperechogenicity that was greater than controls [median area maximal substantia nigra echogenicity (aSNmax) = 0.28 cm(2) vs. 0.14 cm(2), P = 0.005], but similar to idiopathic PD (aSNmax = 0.31 cm(2)). FDG PET (n = 2) demonstrated hypermetabolism of the lentiform nuclei, and F-fluorodopa PET (n = 2), bilateral reduction in striatal F-dopa uptake. Olfaction was markedly impaired in the two tested cases, including onset of smell disturbance in adolescence in one. Neuropsychological features (n = 3) were consistent with Parkinson's disease (PD) or diffuse Lewy body disease (DLB). The imaging, neuropsychological and olfactory markers suggest the GD phenotype includes PD with and without features of DLB, marked olfactory loss, nigral hyperechogenicity on TCS, and F-dopa and FDG PET abnormalities.

Pilot study of a novel computerized task to assess spatial learning in children and adolescents with neurofibromatosis type 1

Difficulties with visual-spatial learning are frequently observed and often considered to be the hallmark of neurocognitive impairment in neurofibromatosis type 1. The computerized Arena Maze is a virtual environment task that has been developed as a human paradigm to the Morris Water Maze, which is used to evaluate spatial learning in animal models. The authors evaluated this task as a measure of spatial learning in children with neurofibromatosis type 1 compared with their unaffected siblings. Affected children were able to learn the task and navigate the virtual environment; however, they performed more poorly on standard measures of spatial learning and spatial working memory than their siblings. The group with neurofibromatosis type 1 demonstrated decreased proficiency in earlier target trials and had more difficulty in remembering target location. This study demonstrates the potential utility of a novel virtual task to assess spatial learning deficits in children with neurofibromatosis type 1.

Neuropsychological Function in Adults With Von Recklinghausen's Neurofibromatosis

The cognitive function of adults with von Recklinghausen's neurofibromatosis (NF-1) was examined. This study sought to replicate in an adult sample the findings of decreased visuospatial and attention abilities reported for many children with NF-1. Specifically, it was anticipated that adults with NF-1 would be classified separately from unaffected controls according to visual and attention-executive function skills. Second, this study examined whether language skills discriminated between adults with NF-1 and unaffected controls. The sample included 20 participants with NF-1 and 25 control participants. All participants were administered a battery of neuropsychological tests (Developmental Test of Visual-Motor Integration (VMI), Judgment of Line Orientation (JLO), Visual Form Discrimination, Booklet Category Test, Figure Cancellation, Peabody Picture Vocabulary Test-Revised (PPVT-R), Sentence Repetition, Controlled Oral Word Association). The results of a discriminant function analysis partially supported the hypothesis: Two of the tests of visual-spatial skill (VMI, JLO) and one of the language tests (PPVT-R) were found to be the best predictors for group membership. The discriminant function accounted for 45% of the variance between the groups and correctly classified 15 of the NF-1 participants and 21 of the control participants. Post hoc exploratory analyses revealed that the VMI was the most important test in discriminating between the groups. It is suggested that patients with NF-1 will tend to have sparing of basic cognitive functions but will have greater impairment on tests that use multiple cognitive skills.

Is judgement of line orientation selectively impaired in right brain damaged patients?

The judgement of line orientation test (JLOT) is widely used to assess visuo-spatial processing. Most neuropsychological studies have shown that on this task right hemisphere damaged (RHD) patients are significantly more impaired than left hemisphere damaged (LHD) patients, suggesting a dominant role of the right hemisphere in discriminating line orientation. To investigate whether other factors can affect performance on JLOT, a modified version of the test, consisting of the 30 original test items and their mirror images, was employed. In Experiment 1 normal participants were more accurate in discriminating the left lines of the original items, and the right lines of the mirror-reversed items, thus indicating that in original JLOT the stimulus arrays comprise lines on the left side that are easier to judge than lines on the right. In Experiment 2, RHD patients with visual neglect were significantly more impaired than patients without neglect, who performed similarly independently from the side of the lesion. Among patients without neglect, however, LHD patients were more accurate than RHD patients without neglect with the original items, but produced more errors than RHD patients without neglect when faced with the mirror-reversed items. Overall, the results of the present study suggest that the greater impairment on standard JLOT shown by RHD patients has to be interpreted as the by-product of the presence of visual neglect, which is more frequent following right hemisphere damage, and of the uneven distribution of the stimulus lines, which are easier to discriminate in the left space. The clinical and theoretical implications of the results are discussed.

Evaluation of practice effects in language and spatial processing test performance

Recent research demonstrates that practice effects are attenuated through the administration of alternate-form memory tests. However, little is known about the degree of practice that can be expected when alternate forms of nonmemory tests are administered repeatedly. Two groups of healthy older adults were assigned to either a same- or alternate-forms condition. Participants completing the same forms of a confrontation naming task improved significantly over 4 testing sessions. On verbal fluency, participant performance significantly improved when completing only alternate forms. No significant practice effects were observed on tests of spatial processing. Practice effects caused by item-specific practice may be reduced via alternate test forms. However, similar reductions will be less apparent when practice effects are the result of test-specific practice.