167 EF and Local-global visual processing in ASD relatives

NYV\WKPɈLYLUJL^HZMV\UKMVY[OLT\S[PWSL_ZHTWSL^OPSLNYV\WKPɈLYLUJLZ did emerge for some EF tasks in this sample. Furthermore, the subscales VM[OL)90,-OH]LHZPTPSHYVYSV^LYLɈLJ[ZPaLJVTWHYLK[V[OL,-[HZRZ [OH[ `PLSKLK ZPNUPÄJHU[ NYV\W KPɈLYLUJLZ ;OLZL ZTHSSLY NYV\W KPɈLYLUJLZ on the questionnaires compared to the tasks may be due to the ‘informant JVU[YHZ[LɈLJ[»+LSH4HYJOLL[HS;OPZPZHYLWVY[PUNIPHZ[OH[YLZ\S[Z from the comparison between ASD probands and their siblings. When ASD parents are asked to score the behaviour of both the ASD probands and his/her siblings, they tend to underestimate the sibling’s atypical behaviour, because the siblings are implicitly compared with the much more severely HɈLJ[LKWYVIHUK4VYLV]LY[OLYLPZL]PKLUJL[OH[HK\S[(:+YLSH[P]LZ[LUK to underestimate their own atypicalities. By using the SRS, De la Marche et al. (2014) indicated that adult ASD relatives presented themselves as slightly more socially responsive than how they were perceived by others. It is possible that this is also the case when they have to report about their cognitive abilities. These reporting biases might have underestimated the KPɈLYLUJLIL[^LLU(:+YLSH[P]LZHUK;+JVU[YVSZVU[OLX\LZ[PVUUHPYLZ;V our knowledge, there is only one other study in which EF questionnaires were HKTPUPZ[LYLK[V(:+YLSH[P]LZ0U[OH[Z[\K`UVNYV\WKPɈLYLUJLZ^LYLMV\UK on the BRIEF (McLean et al., 2014). However, they only reported the results of the Behavior Regulation index (comprising the scales Inhibition, Shifting, and Emotional Control) and the Metacognition index (containing the scales Initiation, Working Memory, Planning/Organization, Organization of Materials, HUK4VUP[VYPUNVM)LOH]PVYI\[UV[VM[OLKPɈLYLU[,-Z\IZJHSLZZLWHYH[LS` -\Y[OLYTVYL[OL`OHKHZTHSSLYZHTWSLVM\UHɈLJ[LK(:+ZPISPUNZHUK [O\ZTPNO[OH]LSHJRLKWV^LY[VKL[LJ[ZTHSSNYV\WKPɈLYLUJLZ0UV\YZ[\K` ^LHSZVVUS`MV\UKZPNUPÄJHU[NYV\WKPɈLYLUJLZPU[OLM\SSZHTWSLI\[UV[PU [OLZTHSSLYT\S[PWSL_ZHTWSLKLZWP[LZSPNO[S`SHYNLYLɈLJ[ZPaLZMVY[OLSH[[LY 4.1.2. Local-global processing

Regarding the local-global processing measures, we found no group KPɈLYLUJLZ VU HU` VM [OL SHIVYH[VY` [HZRZ HUK LɈLJ[ ZPaLZ ^LYL HSS ]LY` ZTHSS;VV\YRUV^SLKNL[OPZPZ[OLÄYZ[Z[\K`L_HTPUPUN[OLWLYMVYTHUJL of ASD relatives with measures aiming to distinguish local and global visual processing abilities as well as visual processing style (see Chapter 5). As a measure of local processing abilities we administered a Visual Search task. To measure global processing abilities, a Coherent Motion task and a Fragmented Object Outlines task were used. And the visual processing style was assessed with the ROCF task. de Jonge et al. (2007) also administered a Coherent Motion task to parents of individuals with ASD and TD parents, HUK[OL`HSZVMV\UKUVNYV\WKPɈLYLUJLZ/V^L]LYHSSV[OLYWYL]PV\ZZ[\KPLZ have used more general Central Coherence (CC) measures, limited to one or more of the following tasks: Block Design, Embedded Figures test, Sentence Completion task and visual illusions (for an overview see Table 1). In most studies the Block Design subtest of the Wechsler intelligence test was simply used to determine PIQ (Fombonne, Bolton, Prior, Jordan, & Rutter, 1997;

168 EF and Local-global visual processing in ASD relatives

7P]LU 7HSTLY ":JOTPK[L[HS":aH[THYPL[HS @L[)€S[L and Poustka (2006) included it as a measure of CC, while all other studies aiming to measure CC, used an adjusted version, comparing performance on a ‘whole’ versus ‘segmented’ condition (de Jonge, Kemner, Naber, & van Engeland, 2009; Happé et al, 2001; Losh et al., 2009). Nevertheless, only Happé et al. (2001) found better performance of ASD fathers compared to ;+JVU[YVSZVU[OPZ[HZR-VYHSSV[OLY**TLHZ\YLZ[OLWH[[LYUVMÄUKPUNZPZ more mixed (see Table 1).

+LZWP[L H SHJR VM NYV\W KPɈLYLUJLZ VU V\Y SVJHSNSVIHS WYVJLZZPUN [HZRZ(:+YLSH[P]LZKPKZJVYLZPNUPÄJHU[S`OPNOLYVU[OL([[LU[PVU[V+L[HPS scale of the DFlex questionnaire (only for the full sample). By administering H KPɈLYLU[ X\LZ[PVUUHPYL )YPZRTHU L[ HS  HSZV YLWVY[LK LUOHUJLK detail focussed processing and a preference for non-social activities for ASD parents (but not for siblings of individuals with ASD). Unfortunately, these questionnaires have a limited construct validity, making it unclear what they actually measure. Therefore, further research is needed to determine whether ASD relatives may indeed show altered local-global processing on more sensitive laboratory task, or whether they are truly similar to TD controls and NYV\WKPɈLYLUJLZVU[OLX\LZ[PVUUHPYLZOH]LHUV[OLYJH\ZL

4.2. Siblings versus parents and full versus multiplex sample

)LZPKLZPU]LZ[PNH[PUNZPTWSLTHPULɈLJ[ZVMNYV\W(:+YLSH[P]LZ]Z ;+ JVU[YVSZ ^L HSZV PU]LZ[PNH[LK ^OL[OLY NYV\W KPɈLYLUJLZ KPɈLYLK MVY ASD siblings compared to ASD parents. For all measures, this was not the JHZL PUKPJH[PUN [OH[ (:+ ZPISPUNZ HUK (:+ WHYLU[Z KPɈLY LX\HSS` MYVT ;+ controls and display a similar degree of ASD-like cognitive characteristics. Strictly speaking, this is also what one would expect from a genetic point of view, since both groups on average share the same amount of DNA with the ASD proband. Previous studies have either reported similar results for (:+ZPISPUNZHUK(:+WHYLU[ZVYTVYLWYVUV\UJLKNYV\WKPɈLYLUJLZMVY[OL parents (see Table 1).

>OLU JVTWHYPUN [OL NYV\W KPɈLYLUJLZ IL[^LLU [OL M\SS HUK [OL multiplex sample, we basically found the same results. No additional group KPɈLYLUJLZ ^LYL MV\UK MVY [OL T\S[PWSL_ ZHTWSL 6U [OL JVU[YHY` NYV\W KPɈLYLUJLZVU[OLX\LZ[PVUUHPYLZ^LYLVUS`ZPNUPÄJHU[MVY[OLM\SSHUKUV[MVY [OLT\S[PWSL_ZHTWSL5L]LY[OLSLZZ[OLLɈLJ[ZPaLZMVY[OLLɈLJ[VMNYV\W were larger for the multiplex compared to the full sample and this was the case for all measures (except for the Planning scale of the BRIEF and the Attention to Detail scale of the DFlex). Since the full sample comprises both T\S[PWSL_HUKZPTWSL_MHTPSPLZ[OLZLÄUKPUNZHYLPUSPUL^P[OHUPUJYLHZLK genetic liability of ASD relatives in multiplex compared to simplex families (as outlined in the Introduction). Given the smaller sample size of the multiplex ]LYZ\Z[OLM\SSZHTWSL[OLYL^HZSLZZWV^LY[VKL[LJ[NYV\WKPɈLYLUJLZHUK [OPZPZWYVIHIS`^O`[OLPUJYLHZLKLɈLJ[ZPaLZKPKUV[YLZ\S[PU[VHKKP[PVUHS NYV\WKPɈLYLUJLZPU[OLT\S[PWSL_JVTWHYLK[V[OLM\SSZHTWSL

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