Esther Vierck

Ongoing adverse mental health impact of the earthquake sequence in Christchurch, New Zealand

Objective: In September 2010 Christchurch, New Zealand, was struck by a 7.1 magnitude earthquake, followed by a prolonged sequence of significant aftershocks including a fatal aftershock in February 2011. Christchurch City has experienced widespread damage, ongoing disruption and building demolitions resulting in many difficulties for the residents of the Christchurch area. We explore what impact the earthquakes have had on the mental and physical health of a random sample of 50-year-olds who live in the Christchurch area. Methods: The 295 participants were selected from the electoral rolls for participation in the CHALICE study, a longitudinal study of ageing. Self-reported health status was assessed using the standardised Short Form 36 version 2 health survey (SF-36v2), a 36-item questionnaire, and results from the eight subscales compared to a national health survey. Mood disorders were assessed and the results were compared to other local and national studies. Results: Since the onset of the earthquakes and throughout the study period, participating middle-aged Christchurch residents have mean SF-36v2 scores significantly lower than population norms in the mental health, vitality, social functioning and role-emotional subscales (Cohen’s d ranged from −0.270 to −0.357, all p < 0.001), while there was no evidence of reduced physical health. Rates of current major depressive disorder were 7.5% in the earthquake survivors compared to 5.1% and 3.7% in other historical, local and national surveys. Similarly, bipolar disorder prevalence was 2.8% in the earthquake survivors compared to 2.2% and 1.4% in other studies. Conclusion: Eighteen months after the first earthquake the significant adverse impact on mental health clearly continues. The ongoing provision of additional mental health services and consideration of these adverse mental health effects in relation to other social policies remains necessary and fundamental.

Congruency Effects between Number Magnitude and Response Force.

Numbers are thought to be represented in space along a mental left-right oriented number line. Number magnitude has also been associated with the size of grip aperture, which might suggest a connection between number magnitude and intensity. The present experiment aimed to confirm this possibility more directly by using force as a response parameter. Participants judged parity of a single digit by executing a weak or forceful key press. Response selection was faster when small digits required a weak response and large digits required a forceful response than when this mapping was reversed. These findings indicate an effect of number magnitude on the initiation of response intensity. There was no evidence for such an effect on response execution because the actually applied response force was not associated with number magnitude. These findings confirm a previously postulated link between different magnitude domains such as number magnitude and intensity as a basis for action. (PsycINFO Database Record (c) 2009 APA, all rights reserved).

Direct selection by color for visual encoding.

In two experiments, we used rapid serial visual presentation tasks to examine the usefulness of color for the direct selection of visual information for perceptual encoding. The participants’ task was to make a discrimination as to whether a target letter within a rapid sequence appeared in its upper- or lowercase version, and an advance cue indicated the color in which the target letter was most likely to occur. To maximize the usefulness of the cued color, in validly cued trials, we used sequences in which the target was the only item appearing in the cued color. In both experiments, accuracy was highest for validly cued trials. A cost-benefit analysis revealed a facilitory effect of valid cues and an inhibitory effect of invalid ones. These results support the idea that color cuing allows the direct selection of objects for further perceptual processing. nt]mis|This research was supported in part by a Marsden grant from the Royal Society of New Zealand to J.M.

SNARC-Like Congruency Based on Number Magnitude and Response Duration

Recent findings demonstrated that number magnitude affects the perception of display time (B. Xuan, D. Zhang, S. He, & X. Chen, 2007). Participants made fewer errors when display time (e.g., short) and magnitude (e.g., small) matched, suggesting an influence of magnitude on time perception. With the present experiment, the authors aimed to extend these findings by investigating whether number magnitude and time are also connected at the response level. Participants judged the parity of single digits by pressing a response key for either a short or a long duration. Responses were faster when small numbers required short keypresses and large numbers required long keypresses. In addition, overall keypress durations were affected by number magnitude. The results suggest a connection between number magnitude and time at the levels of response initiation and execution, thus supporting theories outlining a common magnitude system comprising time, space, and magnitude.

Further evidence for slow binocular rivalry rate as a trait marker for bipolar disorder

Objective: Binocular rivalry refers to a situation where contradictory information is presented simultaneously to the same location of each eye. This leads to the alternation of images every few seconds. The rate of alternation between images has been shown to be slower in euthymic participants with bipolar disorder than in healthy controls. The alternation rate is not uniformly slowed in bipolar disorder patients and may be influenced by clinical variables. The present study examined whether bipolar disorder patients have slower alternation rates, examined the influence of depression and explored the role of clinical variables and cognitive functions on alternation rate. Method: Ninety-six patients with bipolar disorder and 24 control participants took part in the study. Current mood status and binocular rivalry performance were analysed with nonparametric tests. A slow and a normal alternation group were created by median split. We subsequently explored the distribution of several clinical variables across these groups. Further, we investigated associations between alternation rate and various cognitive functions, such as visual processing, memory, attention and general motor speed. Results: The median alternation rate was significantly slower for participants with bipolar disorder type I (0.39 Hz) and for participants with bipolar spectrum disorder (0.43 Hz) than for control participants (0.47 Hz). Depression had no effect on alternation rate. There were no differences between participants with bipolar disorder type I and type II and in regard to medication regime and predominance of one rivalry image. There were also no differences in regard to the clinical variables and no significant associations between alternation rate and the cognitive functions explored. Conclusion: We replicated a slowing in alternation rate in some bipolar disorder participants. The alternation rate was not affected by depressed mood or any of the other factors explored, which supports views of binocular rivalry rates as a trait marker in bipolar disorder.

Precuing Benefits for Color and Location in a Visual Search Task

Selection in multiple-item displays has been shown to benefit immensely from advance knowledge of target location (e.g., Henderson, 1991), leading to the suggestion that location is completely dominant in visual selective attention (e.g., Tsal & Lavie, 1993). Recently, direct selection by color has been reported in displays in which location does not vary (Vierck & Miller, 2005). The present experiment investigated the possibility of independent selection by color in a task with multiple-item displays and location precues in order to see whether color is also used for selection even when target location does vary and supposedly dominant location precues can be used. Precues provided independent information about the location and color of a target, and each type of precue could be either valid or invalid. The precues were followed by brief displays of six letters in six different colors, and participants had to discriminate the case of a prespecified target letter (e.g., R vs. r). Performance was much better when location cues were valid than when they were invalid, confirming the large advantage associated with valid advance location information. Performance was also better with valid advance color information, however, both when location cues were valid and when they were invalid. But these color benefits were dependent on the closeness of the colored letter to the cued location. Our results thus suggest that selection by color in a multiple-item display, where location and color information are independent from each other and equalized, is mediated by location information.

Polyspike and waves do not predict generalized tonic-clonic seizures in childhood absence epilepsy.

About 40% of children with childhood absence epilepsy develop generalized tonic-clonic seizures. It is commonly held that polyspike—wave pattern on the electroencephalogram (EEG) can predict this development of generalized tonic-clonic seizures. However, there is no firm evidence in support of this proposition. To test this assumption, we used survival analysis and compared the incidence of generalized tonic-clonic seizures in 115 patients with childhood absence epilepsy having either isolated 3-Hz spike—wave or coexisting 3 Hz and polyspike—waves and other variables. There was no evidence that polyspike—waves predicted development of generalized tonic-clonic seizures in patients with childhood absence epilepsy. Later age of onset (≥8 years) and family histories of generalized tonic-clonic seizures were the only independent predictors. These results have implications for counseling and in the choice of first-line antiepileptic drugs used for childhood absence epilepsy, especially if valproate is chosen based on the observation of polyspike—waves.

Temperament and character as determinants of well-being.

OBJECTIVES We aimed to evaluate the effects of Temperament and Character Inventory (TCI) personality measures on well-being scores in a sample of 49-51 year old New Zealanders. Previous research has linked high self-directedness (SD) and low harm avoidance (HA) with well-being. We hypothesised that SD and HA would have predictive power for Warwick-Edinburgh Mental Well-being Scale (WEMWBS) well-being. We anticipated that character profiles with high SD and cooperativeness (CO) would be associated with higher well-being scores while high self transcendence (ST) scores would have less of an influence on well-being in a secular population such as New Zealand. Additionally we aimed to describe and assess the performance of a well-being measure, the WEMWBS and we intended to clarify the factors that underlie the questionnaire. METHODS A cohort of 404 randomly selected participants in a study of ageing had WEMWBS means calculated and with principal component analysis used to investigate the factors that underlie the WEMWBS. Multiple hierarchical regression was used to predict WEMWBS scores from socio-demographic and TCI personality variables. ANOVA were used to explore the non-linear effects of personality profiles on well-being. RESULTS Principal components analysis revealed one significant factor which explained 54.34% of the variance. After initial univariate analysis current depression, marital status and standard of living were entered at the first step of the multivariate regression. They explained 20% of the variance. In step two the seven TCI personality variables were added to the model, explaining a total of 49% (R(2) change=0.29). Low HA, high SD and the absence of current depression were the main predictors of WEMWBS scores. Character profiles featuring high SD produced significantly higher scores on the WEMWBS. Total WEMWBS scores were normally distributed, and the mean was 52.83 (95% CI 51.96-53.70). CONCLUSIONS The key determinants of well-being were absence of current depression and personality variables, especially low HA and high SD. The WEMWBS has face validity and the New Zealand results were very similar to the UK results.

Electrophysiological correlates of direct selection by color

We report an experiment using event-related potentials (ERPs) to study selection by color uncontaminated from selection by location. Participants monitored an RSVP sequence for a given target letter that could appear in upper- or lowercase. Prior to the sequence, a cue indicated the most likely color of the target letter. Replicating E. Vierck and J. Miller (2005), upper-/lowercase discrimination accuracy was higher following valid than invalid color cues. Within the ERPs, the target onset produced a negative component between 150 and 350 ms at occipital sites, with shorter latencies following valid than invalid cues. We also found larger amplitude components for valid than invalid color cues at central and parietal sites between 150 and 325 ms. The results not only demonstrate clear effects of color cuing on both behavior and ERPs but also suggest that the observed ERP differences between valid versus invalid trials mediate the behavioral effects.

Effects of task factors on selection by color in the rapid serial visual presentation (RSVP) task

In five experiments, we examined task factors influencing selection by color in a rapid serial visual presentation (RSVP) task. Participants were required to respond to the presence or case of a target letter presented within an RSVP sequence, and they were cued as to the color in which that target was most likely to occur. The first two experiments explored the effect of task difficulty. It was found that a change from the discrimination of upper- versus lowercase targets to the detection of an exact shape had no influence on the color-cuing effect. In contrast, increasing letter set discriminability and decreasing color discriminability reduced the color-cuing effect considerably, although they did not eliminate it. In the third and fourth experiments, the frequency of valid trials was reduced, removing the incentive to use the color information. Again, a small benefit remained, indicating partially automatic and strategic color-processing components. Finally, the fifth experiment showed that an increase in perceptual load had no influence on the color-cuing effect. Together, these five experiments provide further evidence of the robustness of direct selection by color.