Background Deterioration of executive functions in the elderly has been associated with impairments in walking performance. This may be caused by limited cognitive flexibility and working memory, but could also be caused by altered prioritization of simultaneously performed tasks. To disentangle these options we investigated the associations between Trail Making Test performance—which specifically measures cognitive flexibility and working memory—and dual task costs, a measure of prioritization. Methodology and Principal Findings Out of the TREND study (Tuebinger evaluation of Risk factors for Early detection of Neurodegenerative Disorders), 686 neurodegeneratively healthy, non-demented elderly aged 50 to 80 years were classified according to their Trail Making Test performance (delta TMT; TMT-B minus TMT-A). The subjects performed 20 m walks with habitual and maximum speed. Dual tasking performance was tested with walking at maximum speed, in combination with checking boxes on a clipboard, and subtracting serial 7 s at maximum speeds. As expected, the poor TMT group performed worse when subtracting serial 7 s under single and dual task conditions, and they walked more slowly when simultaneously subtracting serial 7 s, compared to the good TMT performers. In the walking when subtracting serial 7 s condition but not in the other 3 conditions, dual task costs were higher in the poor TMT performers (median 20%; range −6 to 58%) compared to the good performers (17%; −16 to 43%; p<0.001). To the contrary, the proportion of the poor TMT performance group that made calculation errors under the dual tasking situation was lower than under the single task situation, but higher in the good TMT performance group (poor performers, −1.6%; good performers, +3%; p = 0.035). Conclusion Under most challenging conditions, the elderly with poor TMT performance prioritize the cognitive task at the expense of walking velocity. This indicates that poor cognitive flexibility and working memory are directly associated with altered prioritization.
Precise interhemispheric interactions constitute a necessary neural basis for bimanual and complex unimanual coordination, because integration of sensorimotor information of both hemispheres is required. At rest, the effect of interhemispheric interactions between homologous motor cortices (M1) is largely inhibitory (Gerloff et al., J. Physiol. (Lond.) 1998; 510, 249–259). In the process of the generation of a movement, interhemispheric inhibition (IHI) between the M1 ipsilateral to the moving hand (iM1) and the M1 contralateral to the moving hand (cM1) turns into facilitation ('release of IHI') close to movement onset (Murase et al., Ann. Neurol. 2004; 55, 400–409). Anatomical studies suggest that callosal connections between homologous M1 are sparse. In fact, denser connectivity exists between premotor cortex (PM) and M1 of the opposite hemisphere (Rouiller et al., Exp. Brain Res 1994; 102, 227–243). As an electrophysiological correlate of the latter, IHI has also been shown between PM and M1 (Mochizuki et al., J. Physiol (Lond.) 2004; 561, 331–338). In the present study, we set out to evaluate the movement-related dynamic modulation of IHI between the PM ipsilateral to the moving hand (iPM) and cM1. Specifically, we hypothesized that IHI from PM to cM1 is modulated earlier that IHI from iM1 to cM1, following a, in part, serial model of premotor and primary motor cortex activation (e.g., Gerloff et al., J. Clin. Neurophysiol. 1998; 15, 502–513).
To evaluate whether enlarged substantia nigra hyperechogenicity (SN+) is associated with an increased risk for Parkinson disease (PD) in a healthy elderly population.
Design
Longitudinal 3-center observational study with 37 months of prospective follow-up.
Setting
Individuals 50 years or older without evidence of PD or any other neurodegenerative disease.
Participants
Of 1847 participants who underwent a full medical history, neurological assessment, and transcranial sonography at baseline, 1535 could undergo reassessment.
Main Outcome Measure
Incidence of new-onset PD in relation to baseline transcranial sonography status.
Results
There were 11 cases of incident PD during the follow-up period. In participants with SN+ at baseline, the relative risk for incident PD was 17.37 (95% confidence interval, 3.71-81.34) times higher compared with normoechogenic participants.
Conclusions
In this prospective study, we demonstrate for the first time a highly increased risk for PD in elderly individuals with SN+. Transcranial sonography of the midbrain may therefore be a promising primary screening procedure to define a risk population for imminent PD.
Plasma levels of amyloid-beta (Aβ) 1-40 peptide have been proposed to be associated with cardiovascular mortality in patients with coronary artery disease (CAD). Therefore, we aimed to investigate the association of plasma Aβ levels with CAD, cardiovascular risk factors (CVRF), and APOE genotype in non-demented elderly individuals.Plasma Aβ1 - 40 and Aβ1 - 42 levels of 526 individuals (mean age of 63.0±7.3 years) were quantified with the INNO-BIA plasma Aβ forms assay based on multiplextrademark technique. APOE genotype was determined with an established protocol. Presence of CAD and CVRFs were ascertained using a questionnaire and/or medical records.Plasma Aβ1 - 40 levels were significantly higher in individuals with CAD (p = 0.043) and, independently, in individuals with diabetes mellitus (DM) type 2 (p = 0.001) while accounting for age- and gender-effects. Plasma Aβ1 - 42 levels were higher in APOEɛ4 carriers (p = 0.004), but were neither relevantly associated with CAD nor with any CVRF. Plasma Aβ1 - 40 showed no association with APOE genotype.Our findings argue for an association of circulating plasma Aβ1 - 40 peptides with incident CAD and DM. Further investigations are needed to entangle the role of Aβ1 - 40 role in the pathophysiology of cardiovascular disease independent of its known role in Alzheimer's disease.
Reduced levels of naturally occurring autoantibodies against amyloid-β (Aβ) have been described in Alzheimer's disease (AD). Lifetime depression doubles the risk of AD, thus these autoantibodies may also be reduced in this group. We measured serum IgG autoantibody titers against Aβ1-42, S100b and α-synuclein in 214 individuals with depression and 419 controls. Titers against Aβ1-42 were lower in individuals with lifetime depression (5544.6 ± 389.3) compared to controls (7208.7 ± 482.4; p = 0.048). Titers against S100b and α-synuclein were comparable between the cohorts. These data suggest an AD-like impairment of the humoral immune response in a relevant proportion of individuals with depression.
Durch experimentelle Untersuchungen in einem Warmeleitungs- und Warmestromungsversuchs-stand wurde eine umfangreiche Datenbasis grundwasserdurchstromter geothermischer Systeme geschaffen. Die experimentellen Untersuchungen konzentrierten sich auf praxisrelevante Stro-mungsgeschwindigkeiten und Heizleistungsbereiche, um eine sinnvolle Erweiterung der aktuell ver-fugbaren Messdaten zu erreichen. Mit Hilfe von experimentellen Untersuchungen in zwei geothermi-schen Feldversuchsstanden konnte die Ubertragbarkeit der Datenbasis auf geothermische Systeme in-situ festgestellt werden. Durch ein anhand der experimentellen Daten kalibriertes und validiertes numerisches Modell konnte die geschaffene Datenbasis in numerischen Untersuchungen uber die experimentellen Untersuchungsgrenzen von Mittel- bis Grobsand hinaus auf Schluff, Feinsand und Kies ubertragen werden.
Auf Grundlage der Datenbasis wurden Empfehlungen zur Dimensionierung geothermischer Systeme unter Berucksichtigung der Grundwasserfliesgeschwindigkeit entwickelt. Der Zusammenhang der Zunahme der effektiven Warmeleitfahigkeit von Sanden in Abhangigkeit der Grundwasserfliesge-schwindigkeit wurde quantitativ erfasst und in tabellarischer Form fur schwach wasserfuhrende, wasserfuhrende und stark wasserfuhrende Sande zusammengefasst. Somit ist es bei der Anwen-dung in der Ingenieurpraxis moglich, nicht nur entsprechend gangiger Tabellenwerke zwischen Warmeleitfahigkeiten fur trockenen, feuchten oder wassergesattigten Sand zu differenzieren, son-dern auch zwischen effektiven Warmeleitfahigkeiten schwach wasserfuhrender, wasserfuhrender und stark wasserfuhrender Sande zu unterscheiden, was einen wichtigen Beitrag zur Weiterent-wicklung der rationellen Energieverwendung darstellt.
SN hyperechogenicity (SN+), determined by transcranial sonography, has been proposed as a risk factor for Parkinson's disease (PD). Recently, we reported a 17.4-fold increased risk for PD in individuals with SN+ older than 50 years within 3 years.This is the second follow-up of a prospective, longitudinal, three-center observational study after 5 years. Of the initial 1,847 at baseline PD-free participants 50 years or older, 1,271 underwent the 5-year reassessment.Within 5 years, 21 individuals developed incident PD. Participants with SN+ at baseline had a more than 20.6 times increased risk to develop PD in this time span than those without this echo feature.We thus confirm our finding of the 3-year follow-up examination in a longer observation time and higher number of individuals with incident PD and suggest SN+ as an important risk marker for PD.
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