Effects of Age on the Temporal Organization of Working Memory in Deaf Signers

Abstract

Temporal organization in WM 2Deaf native signers have a general working memory (WM) capacity similar to that of hearing non-signers but are less sensitive to the temporal order of stored items on retrieval. General WM capacity declines with age, but little is known of how cognitive aging affects WM function in deaf signers. We investigated WM function in elderly deaf signers (EDS) and an age-matched comparison group of hearing non-signers (EHN) using a paradigm designed to highlight differences in temporal and spatial processing of item and order information. EDS performed worse than EHN on both item and order recognition using a temporal style of presentation. Reanalysis together with earlier data showed that with the temporal style of presentation, order recognition performance for EDS was also lower than for young adult deaf signers (YDS). Older participants responded more slowly than younger participants. These findings suggest that apart from age-related slowing irrespective of sensory and language status, there is an age-related difference specific to deaf signers in the ability to retain order information in WM when temporal processing demands are high. This may be due to neural reorganisation arising from sign language use. Concurrent spatial information with the Mixed style of presentation resulted in enhanced order processing for all groups, suggesting that concurrent temporal and spatial cues may enhance learning for both deaf and hearing groups.These findings support and extend the WM model for Ease of Language Understanding (ELU).Key words: working memory; sign language; deafness; temporal processing Temporal organization in WM 3 Working memory (WM) is the cognitive capacity available for on-line processing and short-term storage of information (Baddeley, 2000) and shows a distinctive developmental trajectory over the life-span with increase in capacity during childhood (Davidson, Amso, Anderson & Diamond, 2006) and decline in old age (Reuter-Lorenz & Cappell, 2008).Depletion of WM capacity with advancing age is accompanied by decline in other cognitive functions such as perceptual speed, episodic memory and word fluency (Lindenberger & Ghisletta, 2009). The causal mechanisms of changing WM capacity are yet to be established.Adequate working memory (WM) function is a prerequisite for language processing irrespective of language modality (Baddeley, 2003). However, the architecture of WM in both cognitive and neural terms may differ depending on the modality habitually used (see Rudner,Andin & Rönnberg, in press for a review). Previous work has shown that although there are striking similarities in the architecture of WM for sign-based languages and speech-based languages there are none the less intriguing differences which promise to teach us deeper truths about the nature of this fundamental cognitive function.Sign languages are natural languages that are the preferred medium of communication of people who are born deaf (Emmorey, 2002). Rudner and Rönnberg (2008a) reported a series of studies which ...

The relation between working memory and language comprehension in signers and speakers

“…According to this view, whereas speakers strongly rely on the phonological loop for the storage and recall of linguistic information in WM tasks, signers instead rely on integrated multidimensional memory representations in the episodic buffer that include phonological information, but also, for instance, semantic and spatial information (e.g. Hirshorn et al, 2012; Rudner et al, 2009, 2010, 2013). …”

“…Bavelier, Newport, Hall, Supalla, & Boutla, 2006, 2008; Boutla, Supalla, Newport, & Bavelier, 2004; Geraci, Gozzi, Papagno, & Cecchetto, 2008; Hall & Bavelier, 2011; Wilson, Bettger, Niculae, & Klima, 1997; but see also Andin et al, 2013; Wilson & Emmorey, 2006a, 2006b). Importantly, modality differences are typically not found in backwards serial recall tasks or in tasks with reduced temporal organization demands, such as free recall (e.g., Bavelier, Newport et al, 2008; Boutla et al, 2004; Rudner, Davidsson, & Rönnberg, 2010; Rudner & Rönnberg, 2008a). Moreover, some studies have found that signers outperformed speakers on spatial serial recall tasks, such as the Corsi block test (e.g., Geraci et al, 2008; Romero et al, 2014; Wilson et al, 1997; but see Logan, Mayberry & Fletcher, 1996; Marschark et al, 2015).…”

Preexisting semantic representation improves working memory performance in the visuospatial domain

“…However, other work has shown that effects of phonological similarity on WM for sign language can be elusive (Rudner & Rönnberg, 2008a) despite effects of semantic category 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 (Rudner et al, 2010;Rudner & Rönnberg, 2008a). Indeed in a recent study, it was shown that although deaf users of SSL displayed an effect of phonological similarity on the short term store, as measured by digit span, this effect did not generalize to digit-based WM, as measured by operation span, and when the same experiment was performed with deaf users of BSL, no clear effect of phonological similarity was discernible for either the shortterm store or WM (Andin et al, 2013).…”

“…Group size was estimated on the basis of previous experience with mixed repeated-measures designs, e.g. Rudner, Davidsson and Rönnberg (2010). Details of the groups are shown in Table 1.…”

Neurocognitive factors in sensory restoration of early deafness: a connectome model

“…67 Executive functioning consists of multiple components—ie, working memory, controlled attention, self-monitoring, organisation, inhibition, flexibility-shifting, and goal direction. 68 Verbal working memory, 69,70 controlled cognitive fluency, 67,71 re distribution of attentional resources, 21,72,73 and inhibition–concentration are at risk for delays in individuals with early deafness despite cochlear implantation. 66,74,75 Verbal working memory is assessed with neurocognitive methods that require individuals to hold a sequence of familiar verbal stimuli— eg, digits, letters, or words—in immediate memory while simultaneously engaging in another cognitive activity, such as reversing the order of test items or completing a simple mental calculation (appendix).…”