Critical flicker fusion in primary degenerative dementia of the alzheimer’s type (PDDAT): Clinical implications (II)

Critical Flicker Fusion Threshold (CFFT) and the difference between fusion and flicker thresholds were examined in 23 female and three male patients with Primary Degenerative Dementia of the Alzheimer’s type (PDDAT). The control group consisted of age, sex, and occupational class-matched, normal volunteers. Patients had a mean age of 81.7 years ±6.05 (range 67–89); diagnosis was based on DSM-IIIR criteria. The psychophysical method of limits was used to measure three ascending (fusion) and three descending (flicker) means the average being the CFFT. Both the CFFT and the flicker thresholds were able to distinguish between patients and volunteers at a high level of statistical significance (t=2.054, df=50, p<0.0018 and t=?4.903, df=50, p<0.0000 respectively). Sixty-five percent of patients had CFFT scores below 1.96 SD of the volunteer CFFT mean and 85 percent of patients had flicker thresholds below 1.96 SD of the volunteer flicker mean. The fusion thresholds were not significantly different in the two groups but the fusion thresholds were significantly greater than the flicker thresholds in patients (t=5.617, df=25, p<0.0000). One interpretation of the results in that patients with PDDAT have a significant reduction in the sensitivity of the Central Nervous System to suprathreshold flicker. Accurate diagnosis of early PDDAT (probable Alzheimer’s disease) continues to remain one of the most difficult areas in dementia research. The use of simple quantitative measures such as CFFT may have an important role to play in the overall assessment of patients with PDDAT.     

Critical flicker fusion in normal elderly subjects; a cross-sectional community study

Critical Flicker Fusion Thresholds (CFFTs) were measured in 644 elderly people identified from community-based general practice records, and the relationship of CFFT with age was investigated. The CFFT was measured using the method of limits with mean scores for three ascending (flicker/fusion) and three descending (fusion/flicker) presentations being recorded. The difference between the ascending and descending means was found to be significantly correlated with age (r=−0.131,P<0.001) and may reflect a reduced sensitivity of the Central Nervous System to suprathreshold flicker with increasing age. The results suggest that CFFT measurement has an important role to play in gerontological research as an objective measure of cognitive aspects of the ageing process.     

Issues Involving Informed Consent for Research Participants with Alzheimer’s Disease

Alzheimer’s disease is the most common form of dementia which is estimated to impact 350,000 people over 65 years of age in Canada. The lack of effective treatment and the growing number of people who are expected to be diagnosed with Alzheimer’s disease in the near future are compelling reasons why continued research is in this area is necessary. With additional research, there needs to be greater recognition of the complexity of seeking ongoing informed consent from those with Alzheimer’s disease. This complexity is because the impairment of memory and cognitive ability does not diminish in a linear manner, but rather fluctuates between periods of impairment and relatively normal cognitive lucidness. There is limited discussion in the guidelines of those progressing from early stages of Alzheimer’s disease who have intermittent cognitive function. Guidelines to research and Research Ethics Boards require further development to facilitate researcher including those with Alzheimer’s disease while protecting this growing pool of potential participants.     

Quality of Life in Patients with Recurrent Vasovagal or Unexplained Syncope: Influence of Sex, Syncope Type and Illness Representations

Health-related quality of life (QoL) is reduced in patients with recurrent vasovagal (VVS) or unexplained (US) syncope. Little is known regarding these patients’ QoL as pertains to their capacity to attain their life goals. Factors influencing QoL, such as sex, syncope type and illness representations have not been studied. Our objective is to examine the relationship between illness representations and QoL, as well as possible sex and syncope type differences. One hundred and four patients undergoing tilt-table testing (TTT) for recurrent syncope were interviewed one month before TTT, using questionnaires. Data were analysed using ANCOVAs, a-priori Helmert contrasts for illness representations, and regressions. Patients with US had a poor QoL compared to those with VVS [F(1, 91) = 10.46; p < 0.01], particularly in men (p < 0.01). Patients with higher perceived syncope severity showed an impoverished QoL relative to those with less severe perceptions [F(1, 91) = 5.47; p < 0.05]. A hierarchical regression revealed that illness representations mediate the impact of lifetime number of syncope on QoL. In conclusion, QoL is reduced in these patients, and is influenced by illness representations. Helping patients change their perceptions about their syncope may be an efficient way to promote QoL.     

The Application of Cortical Arousal Assessment to Control Neuromuscular Fatigue During Strength Training

The author's aim was to analyze the cortical arousal response during a conventional strength training session as a method to assess central nervous system fatigue. Sixteen trained men were recruited to perform the maximum number of training series composed of 6 exercises of 10 repetition each, at the intensity of 70% of the 1 maximum repetition, with a rest period of 2 min between exercises and 5 min between series, until exhaustion. Cortical arousal was measured using the critical flicker fusion threshold before, after warm-up, after each exercises series, after the recovery phase between series, and 15 min and 30 min after finishing the training session. Participants could not finish the fourth series of exercise, corresponding with a significant decrease of cortical arousal respect to the warm-up value. The assessment of cortical arousal using CFFT during a strength training session could be a fast and efficient method for assessing central nervous fatigue. Practically, coaches could modify the training protocol according to the individual cortical arousal response in order to improve training efficiency and prevent injuries.     

Sociability/impulsivity and caffeine-induced arousal: Critical flicker/fusion frequency and procedural learning

The influence of sociability/impulsivity in caffeine-induced arousal effects was investigated in two separate experiments: Experiment 1 examined critical flicker/fusion frequency change scores (ΔCFFT) in 60 subjects; and Experiment 2 investigated procedural learning in 30 subjects. In the two experiments, subjects received either caffeine citrate (500 mg) or placebo. The pattern of results was consistent across both studies:(1) a strong interactive effect of sociability (as measured by the EPQ extraversion scale) by caffeine/placebo which showed that (a) subjects low in sociability showed the greatest increase in ACFFT and learned most under placebo, while the reverse was true under caffeine; (b) subjects high in sociability, showed no increase in ΔCFFT and learned least under placebo, while the reverse was true under caffeine; and (2) in neither experiment did impulsivity (as measured by the EPS impulsiveness scale) significantly interact with caffeine/placebo. The results are consistent with Eysenck's (The Biological Basis of Personality, 1967) theory of personality in suggesting that subjects low in sociability are highly arousable under low-arousal (placebo) but over-aroused under high-arousal (caffeine), with the reverse pattern of effects holding for subjects high in sociability. The implications of these data for the respective roles of sociability and impulsivity components of extraversion in arousal-mediated performance are discussed.     

Differences Between African American and White Research Volunteers in Their Attitudes,Beliefs and Knowledge Regarding Genetic Testing for Alzheimer’s Disease

Genetic susceptibility testing for common diseases is expanding, but little is known about race group differences in test perceptions. The purpose of this study was to examine differences between African Americans and Whites in knowledge, attitudes, and motivations regarding genetic susceptibility testing for Alzheimer’s disease (AD). Before enrolling in an AD genetic testing research trial, 313 first-degree relatives of AD patients (20% African American; 71% female; mean age = 58 years) were surveyed regarding: (1) knowledge about genetics and AD risk; (2) concerns about developing AD; and (3) reasons for seeking testing. In comparison to Whites, African Americans were less knowledgeable about genetics and AD risk (p < .01) and less concerned about developing AD (p < .05), with lower levels of perceived disease risk (p = .04). The results suggest that African Americans and Whites differ notably in their knowledge, beliefs, and attitudes regarding genetic testing for AD. Additional research with more representative samples is needed to better understand these differences.     

Volunteer support, marital status, and the survival times of terminally ill patients.

This study examines the possibility that volunteer support can influence how long terminally ill patients survive. Hospice patient files (N = 290) were coded for marital status and volunteer support condition, respectively, the latter on the basis of whether visits from volunteers were requested and received (n = 94), requested but not received (n = 28), or neither requested nor received (n = 168). Baseline health, disease type, and demographic dimensions were comparable across support conditions. Results indicated that when a baseline health status effect was controlled for (p<.0002), patients in the volunteer support condition survived significantly longer than did patients in either unvisited condition (p<.0001). Neither marital status nor gender independently predicted survival time.     

Motilin-and neuropeptide Y-like immunoreactivity in a psychophysiological stress experiment on patients with functional dyspepsia

Background  The aim of the study was to compare plasma motilin-like immunoreactivity (MOT-LI) and neuropeptide Y (NPY)-like immunoreactivity (NPY-LI) in patients with functional dyspepsia (FD) during a controlled psychophysiological experiment. Method  25 patients (12 men, 13 women), age 24–50, with recurrent FD, and 25 pair-wise sex- and age-matched community control subjects were studied. In an experiment, after a rest period, subjects were studied during a 15-min stress interview. The aim of the interview was to elicit anxiety. Before and during the intervention blood samples were drawn for peptide analyses. Outcome measures were the Gastrointestinal Symptom Rating Scale, fasting blood glucose, heart rate and blood pressure as well as the subjects’ self-ratings on visual analogue scales. The plasma concentrations of MOT-LI and NPY-LI are given as anti-logarithms. Results  Mean plasma MOT-LI concentration was 7.3 (CI: 5.7–9.4) pmol/L in the patient group, and 7.9 (CI: 6.1–10.2) pmol/L in the control group. Mean plasma NPY-LI concentration was 14.2 (CI: 12.3–16.4) pmol/L in the patient group, and 13.4 (CI: 11.8–15.3) pmol/L in the control group. Using ANCOVA (covariates: group, gender, age, body mass index and smoking) MOT-LI was related to lower indigestion symptomatology (p<0.04) and positive change in joyfulness during the interview (p<0.03). In the patient group delta motilin correlated with increased joyfulness (p<0.03) and decreased sadness (p<0.03). The NPY-LI increase during the interview was related to higher fasting blood glucose before the interview (p<0.01) and a stronger increase in systolic blood pressure during the test (p<0.05). Conclusion: During a stress interview plasma MOT-LI is positively related to less indigestion symptomatology and joyfulness, while changes in plasma NPY-LI were positively related to sympathetic nervous system activity, but not to gastrointestinal symptoms.     

Motivation as Mediator Between National Identity and Intention to Volunteer

Although there is a large volume of research on the relationship between social identity and volunteerism, little attention was given to national identity in volunteerism research. This study examined the role of national identity in motivating people to volunteer in the Chinese culture and its role in differentiating those who showed no interest in voluntary work (i.e. non‐volunteers) from those who wanted to volunteer but did not (i.e. potential volunteers). Two hundred ninety‐nine participants (age, M = 34.14 years) filled out a questionnaire on their demographics, experience of volunteering, intention to volunteer, volunteer motivations, and national identity. Results showed that a stronger national identity was associated with greater volunteer motivations. Mediation analyses further supported the positive indirect effect of national identity on intention to volunteer through strengthening volunteer motivations. Marital status was the only significant factor that differentiated current volunteers from potential volunteers. We concluded that citizens’ volunteer motivation increases with national identity, yet concrete measures to bring potential volunteers to actual volunteering need to be further explored. Copyright © 2012 John Wiley & Sons, Ltd.