Influence of Age and Sex on Line Bisection: A Study of Normal Performance with Implications for Visuospatial Neglect

Abstract

Line bisection is an established clinical task used to diagnose visuospatial neglect. To date, few studies have considered the extent to which age and sex as background variables contribute to bisection performance. Both variables affect the neural substrates underlying cognitive processes and hence the behavioural performance of bisection. The purpose of this study was to examine the effects of age and sex on normal bisection performance, using three different line lengths to elucidate the influence of these potential contributing factors. Seventy men and 70 women, divided equally into seven age-cohorts between 14 and 80 years, bisected lines. Results indicated clear age- and sex-related differences both in the magnitude and direction of bisection deviations across the three line lengths. Differences are discussed in terms of neural changes across the adult lifespan including hemispheric differences and hormonally mediated changes.

Adult developmental trajectories of pseudoneglect in the tactile, visual and auditory modalities and the influence of starting position and stimulus length

“…Evidence of pseudoneglect on bisection tasks in older adults was also present in the study of Varnava and Halligan (2007) collapsing across gender, though line-length effects did interact with age.…”

“…Some care is thus required in interpreting this finding, though one speculative possibility might be that older young adults within a university setting may have been more efficient in utilizing an arithmetic strategy on mental number line bisection due to increasing Running Head: ADULT DEVELOPMENTAL TRAJECTORIES 22 experience of mathematics use in their studies, though further research is called for to clarify this. The trend towards right bias in visual line bisection (a non-significant association between age and reduced left bias in the older adult sample) is a somewhat equivocal result that contributes to a similarly equivocal literature where some reports indicate a decline in left bias in visual bisection (Barret et al, 2008;Chen et al, 2011) whilst some so do not (Failla et al, 2003;Varnava & Halligan, 2007;Brooks et al, 2011). We note that the present data form a non-significant trend only apparent in the older adult sample when that sample is considered on its own, and as thus have limited explanatory power.…”

“…Reduced or reversed rightward biases have been reported on visuo-spatial line bisection or landmark tasks (where participants classify pre-bisected line stimuli: Barrett & Craver-Lemley, 2008;Benwell, Thut, Grant & Harvey, 2014b;Schmitz & Peigneux, 2011;Goedert, LeBlanc, Tsai & Barrett, 2010; see also Schmitz, Dehon & Peigneux, 2013). There is also evidence that males and females may produce differential patterns of pseudoneglect over aging, with older females exhibiting more consistent left biases, whilst older males may exhibit a drift into rightward bias with age (Varnava & Halligan, 2007;Chen, Goedert, Murray, Kelly, Ahmeti, Barrett, 2011). Meanwhile there is evidence for reduced lateral bias in older participants in lateralised visual detection tasks (Learmonth, Thut, Benwell & Harvey, 2015;Nagamatsu, Carolan, Liu-Ambrose & Handy, 2011;Nagamatsu, Munkacsy, Liu-Ambrose & Handy, 2013).…”

“…Visuo-spatial line bisection tasks have adopted different line lengths; lines up to 28cm (Rueckert et al, 2002), 20cm (Varnava and Halligan 2007), 16cm (Brodie & Dunn, 2005); and 25 cm (calculated from visual angle) (McCourt & Jewell, 2000). In the current study the lines fell outside these typical ranges because it would not have been suitable to employ a 1cm rod, for example, for tactile rod bisection.…”

Age-related differences in distractor interference on line bisection

“…Some studies reported a rightward bias in older participants (Failla et al 2003;Fujii et al 1995); others did not find any deviational bias (Barrett and Craver-Lemley 2008; Beste et al 2006). Varnava and Halligan (2007) examined whether age and sex-related differences influenced bisection performance. Men and women were divided equally into seven age cohorts between 14 and 80 years.…”