The effect of retirement on cognitive functioning

Cognitive impairment has emerged as a major driver of disability in old age, with profound effects on individual well-being and decision making at older ages. In the light of policies aimed at postponing retirement ages, an important question is whether continued labour supply helps to maintain high levels of cognition at older ages. We use data of older men from the US Health and Retirement Study to estimate the effect of continued labour market participation at older ages on later-life cognition. As retirement itself is likely to depend on cognitive functioning and may thus be endogenous, we use offers of early retirement windows as instruments for retirement in econometric models for later-life cognitive functioning. These offers of early retirement are legally required to be nondiscriminatory and thus, inter alia, unrelated to cognitive functioning. At the same time, these offers of early retirement options are significant predictors of retirement. Although the simple ordinary least squares estimates show a negative relationship between retirement duration and various measures of cognitive functioning, instrumental variable estimates suggest that these associations may not be causal effects. Specifically, we find no clear relationship between retirement duration and later-life cognition for white-collar workers and, if anything, a positive relationship for blue-collar workers.     

The internal responsiveness of the Oral Health Impact Profile-14 to detect differences in clinical parameters related to surgical third molar removal

Purpose

The present study examined the internal responsiveness of the short-form Oral Health Impact Profile (OHIP-14) and its ability to differentiate between patients with and without pre- and postoperative complaints as well as other clinical variables.

Methods

The sample consisted of 97 patients undergoing surgical third molar removal. The OHIP-14 was filled in preoperatively, on each postoperative day for a week and once more after 1?month. In addition, pre- and postoperative status was measured along with other clinical variables.

Results

The OHIP-14 is able to differentiate between the first preoperative day (M?=?16.85, SD?=?5.35) and all the days within the postoperative week (first day M?=?29.46, SD?=?9.32). One month postoperatively, mean OHIP scores are reduced to preoperative levels. In addition, differences could be shown between patients with and without pre- (M?=?18.9, SD?=?8.1 vs. M?=?16.2, SD?=?3.9) and postoperative complaints (M?=?18.9, SD?=?8.1 vs. M?=?16.2, SD?=?3.9), partial (preop; M?=?17.8, SD?=?6.8, postoperative; M?=?27.4, SD?=?7.7) and complete mucosa coverage (preop; M?=?15.9, SD?=?3.2, postoperative; M?=?29.5, SD?=?10.6) and the level of impaction (Pell and Gregory classification) of the third molar (3B showing the highest increase in the mean OHIP score).

Conclusions

The OHIP-14 can be considered internally responsive to changes in impacts of oral conditions as a result of surgical third molar removal and is able to differentiate the effect of several clinical variables.     

High titer anti-HIV antibody reactivity associated with a paraprotein spike in a homosexual male with AIDS related complex

We observed a human immunodeficiency virus (HIV)-infected homosexual male with AIDS related complex (ARC) who had a serum globulin level of 80 g/L. Serum protein electrophoresis revealed a gamma globulin fraction of 40 g/L, of which 50% (20 g/L) was contained within a paraprotein spike, comprised predominantly of IgG kappa. This patient also had high titer anti-HIV antibodies in his serum, which were Western blot reactive at a final dilution of 1:500,000, and recognized gp120env, p66pol, p55gag, p53pol, p41gag, and p24gag. Because paraproteins in the past have been shown to be directed against specific antigens, we purified this patient's paraprotein using a modified high performance liquid chromatography (HPLC)-hydroxylapatite procedure and tested the purified paraprotein for anti-HIV antibody activity. The purified paraprotein retained anti-HIV antibody activity to a final dilution of 1:100,000, and recognized p66pol, p55gag, p53pol, p41gag, and p24gag. The recognition of both "gag" and "pol" gene products suggested that the purified paraprotein might not be monoclonal in origin. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated that the purified paraprotein contained at least two immunoglobulin light chain species (Mol wt 30 to 33 Kd). Affinity chromatography of the purified paraprotein using a p24- Sepharose 4B matrix separated the "gag" and "pol" antibody activities. Immunoglobulin gene rearrangement analysis of a bone marrow aspirate (which contained 15% plasma cells) failed to reveal a clonal population of immunoglobulin producing cells. We conclude that this patient's paraprotein accounted for most of the anti-HIV activity present in whole serum, and that this paraprotein was not monoclonal in origin.     

Long–echo time MR spectroscopy for skeletal muscle acetylcarnitine detection

Animal models suggest that acetylcarnitine production is essential for maintaining metabolic flexibility and insulin sensitivity. Because current methods to detect acetylcarnitine involve biopsy of the tissue of interest, noninvasive alternatives to measure acetylcarnitine concentrations could facilitate our understanding of its physiological relevance in humans. Here, we investigated the use of long–echo time (TE) proton magnetic resonance spectroscopy (¹H-MRS) to measure skeletal muscle acetylcarnitine concentrations on a clinical 3T scanner. We applied long-TE ¹H-MRS to measure acetylcarnitine in endurance-trained athletes, lean and obese sedentary subjects, and type 2 diabetes mellitus (T2DM) patients to cover a wide spectrum in insulin sensitivity. A long-TE ¹H-MRS protocol was implemented for successful detection of skeletal muscle acetylcarnitine in these individuals. There were pronounced differences in insulin sensitivity, as measured by hyperinsulinemic-euglycemic clamp, and skeletal muscle mitochondrial function, as measured by phosphorus-MRS (³¹P-MRS), across groups. Insulin sensitivity and mitochondrial function were highest in trained athletes and lowest in T2DM patients. Skeletal muscle acetylcarnitine concentration showed a reciprocal distribution, with mean acetylcarnitine concentration correlating with mean insulin sensitivity in each group. These results demonstrate that measuring acetylcarnitine concentrations with ¹H-MRS is feasible on clinical MR scanners and support the hypothesis that T2DM patients are characterized by a decreased formation of acetylcarnitine, possibly underlying decreased insulin sensitivity.     

Relation between education and dementia: the role of test bias revisited.

Several authors have suggested that dementia screening tests may be biased against low levels of education, whereas others find that a low level of education is a genuine risk factor for dementia. The present paper attempts to reconcile these conflicting views by examining item bias and test bias indices of the mini mental state examination (MMSE). Psychometric calculations and receiver operating characteristics (ROC) analyses of sensitivity and specificity as performed by earlier studies were replicated and extended from the database of the Amsterdam Study of the Elderly. This is a population survey on cognitive decline and dementia (age range 65-84). Subjects with a low level of education (primary school) were compared with better educated subjects (at least some secondary education). Cases were matched by age and sex. The results indicate that the MMSE is not educationally biased as far as item characteristics, reliability, and construct validity are concerned. Yet its predictive validity as a screening test for dementia is educationally biased. This bias will effectively be eliminated with a two point higher cut off score for the subjects whose education extends beyond primary school. Even after such score correction, a low level of education probably remains a genuine risk factor for dementia.     

First case of an oculofacial lesion due to Mycobacterium haemophilum infection in an immunocompetent child.

Oculofacial lesions caused by infections with nontuberculous mycobacterial organisms are unusual, but infections with Mycobacterium haemophilum species in immunocompetent patients have not yet been described. We present a case of an oculofacial lesion in a girl as a result of a Mycobacterium haemophilum infection.     

Cognitive complaints in patients after whiplash injury: the impact of malingering

OBJECTIVES—The validity of memory andconcentration complaints that are often reported after a whiplashtrauma is controversial. The prevalence of malingering orunderperformance in post-whiplash patients, and its impact on theircognitive test results were studied.
METHODS—The Amsterdam short term memory (ASTM)test, a recently developed malingering test, was used as well as aseries of conventional memory and concentration tests. The study samplewas a highly selected group of patients, who were examined either aspart of a litigation procedure (n=36) or in the normal routine of anoutpatient clinic (n=72).
RESULTS—The prevalence of underperformance, asdefined by a positive score on the malingering test, was 61% (95% CI:45-77) in the context of litigation, and 29% (95% CI: 18-40) in theoutpatient clinic (p=0.003). Furthermore, the scores on the memory andconcentration test of malingering post-whiplash patients (n=43) andnon-malingering post-whiplash patients (n=65) were compared with thescores of patients with closed head injury (n=20) and normal controls(n=46). The malingering post-whiplash patients scored as low as thepatients with closed head injury on most tests.
CONCLUSIONS—The prevalence of malingering orcognitive underperformance in late post-whiplash patients issubstantial, particularly in litigation contexts. It is not warrantedto explain the mild cognitive disorders of whiplash patients in termsof brain damage, as some authors have done. The cognitive complaints ofnon-malingering post-whiplash patients are more likely a result ofchronic pain, chronic fatigue, or depression.