ISSN (Online) Commun Sci Disord 2017;22(3): Original Article Diagnostic Accuracy of Working Memory

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1 ISSN (Online) Commun Sci Disord 2017;22(3): Original Article Diagnostic Accuracy of Working Memory Tasks Depending on Scoring Unit and Condition in Preschool Children Dongsun Yim, Shinyoung Kim, Jeewon Yoo, Yunjung Lee, Sangeon Lee, Haeun Chung Department of Communication Disorders, Ewha Womans University, Seoul, Korea Correspondence: Dongsun Yim, PhD Department of Communication Disorders, Ewha Womans University, 52 Ewhayeodae-gil, Seodamun-gu, Seoul 03760, Korea Tel: Fax: Received: April 10, 2017 Revised: May 16, 2017 Accepted: June 5, 2017 Objectives: The purpose of the current study was to examine the diagnostic accuracy of working memory (WM) tasks, including nonword repetition (NWR), sentence repetition (SR), and matrix tasks, as clinically efficient diagnostic tools depending on the scoring systems and task condition. Methods: Forty children with vocabulary delay (VD group) and 40 typically developing children (TD group) were administered a series of WM tasks (NWR, SR, and matrix tasks). Different scoring units were applied to each task (syllable vs. word for NWR task and word vs. sentence for SR task) while different conditions (forward matrix vs. backward matrix) were used for the matrix task. Separate discriminant function analyses were conducted with the scores calculated by the different scoring units or the different condition of the tasks as predictors. Results: Multiple discriminant function analyses for the NWR task yielded word units with higher overall classification values than syllable units, whereas for the SR task sentence units had a higher overall classification value than word units. For the matrix task, none of the conditions reached the level of significance in the discriminant function analyses. Conclusion: The results in this study support the diagnostic accuracy of the NWR task with word units and the SR task with sentence units in discriminating among the VD group and the TD group. However, caution should be used when regarding these matrix tasks as an accurate diagnostic tool, especially in young children. Keywords: Nonword repetition, Sentence repetition, Matrix, Discriminant function analyses, Diagnostic accuracy 양육자및교사의의뢰로언어장애의가능성이있는아동들이임상현장에오게되면임상가는선별검사와진단검사를통해아동의언어장애여부를판별한다. 이때임상가는아동의증상과연령, 보호자의보고를종합적으로고려하여아동에게나타나는언어적결함의세부적영역에대해구체적으로평가한다. 언어평가는공식검사 (formal test; standardized test) 와비공식검사 (informal test), 직접검사와간접검사등으로나눌수있는데 (Kim, 2014), 일반적으로타당도와신뢰도가검증되었으며규준을제공할수있는공식검사를우선적으로실시하되대상아동이가진구체적인언어문제에대한심화평가의수단으로다양한비공식검사를추가적으로실시한다 (Tyler & Tolbert, 2002). 그런데현재임상에서사용되고있는검사도구들은매우제한적인실정이며 (Kim, 2014; Kim, Park, & Lee, 2005; Lee, 2006), 많은임상가들은본인에게의뢰된아동의언어능력을정밀하게평가하기위하여외국의공식검사를번역하여사용하거나, 혹은다양한연구들에서개발한언어평가과제들을활용하고있다 (Oh & Yim, 2013; Vandierendonck & Szmalec, 2004; Yim, 2017; Yim, Jo, Han, & Sung, 2016). 그러나, 공식검사와달리비공식검사는객관적인규준이없고, 대부분의경우연구에서사용된검사를차용함으로써각연구의목적에따라검사의진행방식이나채점방식등이일치되지않아임상에서활용할때범용이어렵다는제한점이있다. 특히작업기억 (working memory) 이언어능력의주요기저요인으로주목받아온이후작업기억을평가하는다양한과제들이임상에서사용되고있으나 (Kane et al., 2004; McNamara & Wong, 2015; Menghini, Copyright 2017 Korean Academy of Speech-Language Pathology and Audiology This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( by-nc/4.0) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited

2 Dongsun Yim, et al. Diagnostic Accuracy of Working Memory Tasks Finzi, Carlesimo, & Vicari 2011; Park et al., 2002), 각과제의수행결과를채점하는방식이검사도구마다, 혹은과제를사용한연구들마다일관적이지않다. 특히비공식검사에서이러한과제들을사용하는경우어떤방식을적용하느냐에따라과잉진단 (over diagnosis) 또는오진단 (under diagnosis) 의가능성으로인해선별및진단의정확도가저해될수있음을주의해야한다. 따라서아동의언어능력을세밀하게평가하기위한비공식검사들의진단도구로서의기능을검증하기위하여, 언어장애를정확하고효과적으로판별할수있는채점체계에대한연구가필요하다. 국내외에서자주사용되는비공식검사들중, 비단어따라말하기과제, 문장따라말하기과제는 Baddeley의다중요소작업기억모델을기반으로자주논의되어왔다. Baddelely가제안한다중요소작업기억모델에의하면, 작업기억은언어적정보또는비언어적정보등영역-특정적 (modality-specific) 정보를저장하는동시에해당정보를조작하고처리하는능력을말한다 (Baddeley & Hitch, 1974; Baddeley, 1986, 2000). Baddelely의작업기억모델은핵심구성요소인중앙집행기 (central executive) 와 3개의하위체계로구성되어있다. 중앙집행기는작업기억모델에서저장된정보와처리하는정보사이에가용할수있는자원을할당하며정보를조작및처리하는데중심적역할을하는구성요소로알려져있으며, 3개의하위체계는언어적정보를저장하는음운루프 (phonological loop), 비언어적정보를저장하는시공간스케치패드 (visuospatial sketch pad), 그리고장기기억에저장된정보들과중앙집행기및언어적, 비언어적정보들을통합하며처리하는다차원적저장소인임시완충기 (episodic buffer) 가있다 (Baddeley, 2007; Baddeley, Allen, & Hitch, 2010). 임상에서는특히비단어따라말하기, 문장따라말하기검사가많이사용되고있는데 (Martin, & Schwartz, 2003), 이들과제는각각작업기억의구성요소중음운루프와임시완충기를측정하는과제로알려져있다 (Petruccelli, Bavin, & Bretherton, 2012). 비단어따라말하기과제 (nonword repetition task) 는피실험자가다음절로구성된비단어를듣고음운정보를저장하여그대로다시따라말하는과제로, Baddeley의작업기억모델의구성요소중음운루프가관여한다. 비단어따라말하기과제는많은선행연구들에서다양한언어능력, 예를들어어휘력, 어휘습득능력 (Botting & Conti-Ramsden, 2001; MacRoy-Higgins & Dalton, 2015; McKean, Letts, & Howard, 2013; Yim et al., 2016), 언어이해능력 (Yim, Kim, & Yang, 2015; Yang, Yim, Kim, & Han, 2013), 읽기능력 (Melby-Lervag & Lervag, 2012; Rispens, Baker, & Duinmeijer, 2015; Rispens & Baker, 2012) 등과정적상관관계를가지고있으며, 나아가단순언어장애 (Archibald & Joanisse, 2009; Bishop, North, & Donlan, 1996; Conti-Ramsden, Botting, & Faragher, 2001), 자폐범주성장애 (Botting & Conti-Ramsden, 2003), ADHD (Redmond, Thompson, & Goldstein, 2011) 등다양한장애군을선별하는유용한도구가될수있음이검증되어왔다. 현재국내외공식적 비공식적언어처리능력평가과제로비단어따라말하기과제가빈번하게사용되고있으나 (Dollaghan & Campbell, 1998; Hong & Yim, 2014; Windsor, Kohnert, Lobitz, & Pham, 2010; Yim, Kim, et al., 2016), 수행결과에대한채점단위는통일되어있지않다. 비단어따라말하기과제는제시된비단어의음절모두를정확하게따라말했을경우 1점을부여하는낱말단위채점방식 (Tattersall, Nelson, & Tyler, 2015; Yim et al., 2016) 과, 음절단위로각 1점씩부여하는음절단위채점방식이주로행해지고있으며 (Burke & Coady, 2015; Oh & Yim, 2013; Yim, Kim, & Yang, 2016), 음소단위채점방식을적용한선행연구도찾아볼수있다 (Brandeker & Thordardottir, 2015; Dollaghan & Campbell, 1998; Hong & Yim, 2014; McKean et al., 2013). 국내에서도비단어따라말하기의임상적선별도구로서의가능성을검토한많은선행연구들이진행되어왔으며 (Hong & Yim, 2014; Yim, Kim, et al., 2016), 채점단위로는낱말단위 (Yim et al., 2015) 와음절단위 (Oh & Yim, 2013; Yang et al., 2013) 로점수를산출한연구가주를이룬다. 국내의경우 4세이상아동들의초기문해수준을평가하는공식검사 (Basic Academic Skills Assessment, BASA; Early Literacy; Kim, 2008) 에서는낱말단위채점방식을적용하고있으며, 읽기검사를평가하는한국어읽기검사 (Korean Language-based Reading Assessment, KOLAR; Pae, Kim, Yoon, & Jahng, 2015) 및읽기성취및읽기인지처리능력검사 (Test of Reading Achievement & Reading Cognitive Processes Ability, RA-RCP; Kim, Kim, Hwang, & Yoo, 2014) 에서도낱말단위채점방식을적용하고있다. 국외의경우음운처리능력을평가하는 Comprehensive Test of Phonological Processing-second edition (CTOPP-2; Wagner, Torgesen, Rashotte, & Pearson, 2013) 에서는낱말단위채점방식을적용하고있다. 다수의선행연구에의하면채점방식과무관하게거의대부분의연구들에서언어장애아동집단과일반아동집단간과제수행력의차이가유의하였다 (Dollaghan & Campbell, 1998; Yang et al., 2013). 또한비단어따라말하기과제의채점단위간차이를비교검토한선행연구 (Guiberson & Rodriguez, 2013) 에서는, 낱말단위채점방식과음소단위채점방식이모두유의하게언어장애집단과일반아동집단을유의하게판별하는것으로났으나, 민감도 (sensitivity) 와특이도 (specificity) 로판단한언어장애집단판별력은낱말단위채점방식이더높은것으로나타났다

3 채점단위및수행조건에따른작업기억과제의언어장애진단정확도비교연구 임동선외 문장따라말하기과제는피실험자가문장을듣고그대로따라말하는과제로, 과제를수행하면서어휘및문장구조에관한정보를기억하고재구성해야한다. 따라서 Baddely의작업기억모델구성요소중장기기억및집행기능이통합적으로개입하는임시완충기가관여하여, 이를측정하는과제로사용되어왔다 (Alloway, Gathercole, Willis, & Adams, 2004; Petruccelli et al., 2012). 문장따라말하기과제는구문능력등일반적언어능력을측정할뿐아니라 (Klem et al., 2015) 단순언어장애및언어능력결함을진단하는검사로폭넓게사용되고있다 (Archibald & Joanisse, 2009; Eadie, Fey, Douglas, & Parsons, 2002; Hansson, Nettbelbladt, & Leonard, 2003; Hwang, 2003; Poll, Betz, & Miller, 2010; Riches, 2012). 국외의경우문장따라말하기과제는 Clinical Evaluation of Language Fundamentals-fourth edition (CELF-4; Semel, Wiig, & Secord, 1989), Test of Language Development Primary-third edition (TOLD-P3; Newcomer, & Hammill, 1997) 과 Wechsler Preschool and Primary Scale of Intelligence-Revised (WIPPSI-R; Wechsler, 1989) 등과같은공식검사의하위검사에서사용되고있는데, 각검사들에서사용하는과제의채점단위가서로통일되어있지않다. CELF-4 (Semel et al., 1989) 에서는오류의개수에따라채점하는데, 문장을완전하게따라하면 3점, 오류가 1개일때 2점, 오류가 2-3개일때 1점, 오류가 4개이상일때 0점으로처리한다. 이에반해, TOLD-P3 (Redmond, 2005) 에서는문장단위의채점방식이적용되고있고, WIPPSI-R 의하위검사인문장따라말하기과제를사용한연구에서는 (Eadie et al, 2002) 문법형태소단위의채점방식이적용하였다. 국내의경우공식검사인 RA-RCP (Kim et al., 2014) 의하위검사중하나인문장따라말하기과제에서는문장단위채점방식을사용하고있으며, 취학전아동의수용언어및표현언어발달척도 (Preschool Receptive- Expressive Language Scale, PRES; Kim, Sung, & Lee, 2003) 에서는일부문항에서문장단위채점방식의문장따라말하기검사를실시하고있다. 공식검사외에말늦은아동과일반아동 (Oh & Yim, 2013), 단순언어장애아동과일반아동 (Kang & Kang, 2016; Lee, Choi, & Hwang, 2014), 읽기부진아동과일반아동 (Hwang, 2014) 간문장따라말하기과제의수행력차이를비교한국내의다양한선행연구에서사용된채점방식은일관적이지않으며, 음절단위로채점하여점수를산출한연구 (Kang & Kang, 2016; Lee et al., 2014) 와문장단위로채점하여점수를산출한연구 (Oh & Yim, 2013; Park, Yoon, Han, & Yim, 2014) 등이혼재되어있다. 한편, 문장따라말하기과제의채점체계를네가지 ( 문장단위, 문장성분, 오류횟수, 음절단위 ) 로분류하여아동의수용어휘능력을가장잘예측하는방식이무엇인지검토한선행연구 (Park et al., 2014) 에의하면, 대상 아동의수용어휘능력을가장잘예측하는것은문장단위의평가방식인것으로나타났다. 다만이연구에서는문장단위채점방식은점수획득이어려워아동의반응을과소평가할가능성이높으므로결과해석에주의해야함을밝혔다. 5-6세아동들을대상으로한선행연구 (Hwang, 2012) 에서는 6세아동의경우문장단위점수나낱말단위점수의판별력에차이가없었으나, 5세아동의경우문장단위점수가낱말단위점수보다판별력이높게나타났으며, 이에따라문장단위점수로진단정확도를검증한결과 5세와 6세집단모두에서민감도 (sensitivity), 특이도 (specificity), 예측도 (predictive value) 가모두 85% 이상으로높게나타나문장따라말하기검사의단순언어장애진단도구로서의유용성을확인하였다. 한편, 언어적작업기억에대한연구에비해시공간작업기억과언어장애의관계를밝힌연구는상대적으로드물다. 하지만, 난독증아동집단과일반아동집단간비언어적작업기억의유의한차이를밝힌선행연구 (Menghini et al., 2011) 및학습장애아동들이일반아동들에비해비언어적작업기억과제에서유의하게낮은수행결과를보였다는선행연구 (McNamara & Wong, 2015) 에의하면, 작업기억이영역 -일반적인(domain-general) 인지능력으로써언어적작업기억과비언어적작업기억이모두언어능력과관련이있다고볼수있다. 다양한언어적작업기억과비언어적작업기억과제를대상으로요인분석을실시하여두영역이상당한양의분산을공유함을밝힌선행연구 (Kane et al., 2004; Park et al., 2002) 와언어장애아동들이비언어적기억능력에도결함이있음을보인선행연구 (Im Bolter, Johnson, & Pascual Leone, 2006; McNamara & Wong, 2015; Menghini et al., 2011) 등은이러한입장을지지하나, 반면단순언어장애아동들의경우비언어적작업기억의능력은언어적작업기억에비해상대적으로보존된다는선행연구 (Archibald & Gathercole, 2006) 등은반대의입장을견지한다. 즉, 작업기억이영역-일반적인 (domain-general) 인지능력인지아니면영역-특정적인 (domain-specific) 인지능력인지에대한합일된의견이있다고할수없지만, 언어의사용이제한적인장애아동들에게있어비언어적과제는언어적관여를최소화할수있어아동의능력을평가하는데더욱적합할수있다는점을고려한다면, 비언어적기억과제의수행과언어적작업기억의결함이뚜렷한언어장애군과의연관성에대한연구는필요하다. 언어장애의기저원인으로제시되는음운작업기억등언어적작업기억에대한연구는다양한과제들을통해광범위하게진행되어온반면, 시공간적작업기억 (visuospatial sketchpad) 은시각적패턴이나시각적자극제를이용하여일련의움직임을순서대로혹은역순으로회상하는과제를이용하여측정해왔는데, 대표적으로 487

4 Dongsun Yim, et al. Diagnostic Accuracy of Working Memory Tasks 코지블록과제 (Corsi block task; Cowan, Donlan, Newron, & Lloyd, 2005), 시각패턴과제 (visual pattern task; Della Sala, Gray, Baddeley, Allamano, & Wilson, 1999), 점매트릭스과제 (dot-matrix task; Vugs et al., 2014, 2016) 등이있다. 일반적으로시각적자극을기억했다가순서대로회상하는과제는피실험자의시공간적단기기억을측정하는과제로주로사용되는반면, 역순으로회상하는과제는시공간적작업기억을측정하는과제로사용되고있다 (Vandierendonck & Szmalec, 2004). 그러나 8-11세아동을대상으로세가지시각자극을순서대로회상하는과제와역순으로회상하는과제를비교한선행연구 (Hutton & Towse, 2001) 에서는성인과달리아동들의경우두가지과제가동일한인지적기억 (memory) 영역을측정함을밝힌바있다. 국외의선행연구에서는아동의시공간적작업기억을측정하는과제로 Automated Working Memory Assessment (AWMA; Alloway, Gathercole, & Pickering, 2004) 와 Working Memory Test Battery for Children (WMTB-C; Pickering & Gathercole, 2001) 의하위검사들이주로사용되고있는데, 해당검사들의경우모두점이나도형, 블럭들의위치를순서대로회상하게한다. 본연구는작업기억의각하위체계들을측정하는과제들의언어장애진단정확도를분석하고자한다. 이를위하여각케이스가속한집단을예측하여집단을분류하는방식인판별분석을통하여실제언어장애아동중해당과제를통하여언어장애집단으로진단되는비율인민감도 (sensitivity) 및실제일반아동중해당과제를통하여언어장애집단에서배제되는비율인특이도 (specificity) 를검토하고자한다. 또한본연구에서는장애의유병률에영향받지않는진단정확도로써우도비를측정하였는데, 비장애임에도해당검사에서장애로진단되는경우를반영한양성우도비와실제장애가있음에도비장애로진단되는경우를반영한음성우도비는, 각각해당검사에서장애로진단된경우실제로장애가있을진단정확도 (rule-in) 와해당검사에서비장애로진단된경우실제로장애가없을진단정확도 (rule-out) 를의미한다고할수있다 (Guiberson & Rodriguez, 2013). Guiberson 과 Rodriguez (2013) 는양성우도비가 10 이상일때해당장애의진단정확도 (rule-in) 가높다고할수있으며, 3 이상일때에는제한적이지만용인할수있는수준, 양성우도비가 1일때에는진단적도구로서사실상의미가없다고보았다. 또한음성우도비가 0.1 이하인경우진단의정확도 (rule-out) 가높다고할수있으며, 0.3 이하인경우제한적이지만용인할수있는수준, 음성우도비가 1인경우진단적도구로서사실상의미가없다고보았다. 다른연구 (Dollaghan & Horner, 2011; Fischer, Bachmann, & Jaeschke, 2003) 에서는양성우도비가 10 이상또는음성 우도비가 0.1 이하인경우임상적진단의잠재력이있는것으로보았으며, 양성우도비가 5에서 10 사이, 음성우도비가 0.1에서 0.2 사이일때에는부가적으로유용한정보를제공해줄수있을정도의진단적가치를갖고있는것으로보았다. 또한양성우도비가약 3, 음성우도비가약 0.30의범위에있는경우다소제한적으로만임상적결정에영향을미칠수있다고하였으며, 양성우도비와음성우도비가 1에가까울수록임상적인유용성이낮은것으로보았다. 요약하자면, 비단어따라말하기과제와문장따라말하기과제는많은선행연구들에서다양한언어장애아동집단과일반아동집단간수행력차이가유의하게나타나는등그임상적유용성이검증되어왔다. 하지만, 동일한내용의과제를사용하면서도실시방법이나채점방식은여전히연구들마다다르며, 이에대해특히진단정확도만을목적으로한판별연구는많지않다. 또한명확히구분되는임상적집단을대상으로작업기억의세하위체계를다각적으로측정하면서각과제가해당집단을얼마나정확하고효과적으로변별할수있는지를검토하는연구는찾아보기어렵다. 한편학령전기아동의어휘력은이후의언어능력 (Lee, 2011; Storch & Whitehurst, 2002) 및학업성취도 (Morgan, Farkas, Hillemeier, & Hammer, 2015; Walker, Greenwood, Hart, & Carta, 1994) 를예측하는주요요인인바, 어휘발달이또래에비해지체된아동에대한정확한진단과이에따른신속하고효과적인개입이필요하다. 따라서, 본연구에서는어휘발달지체아동과일반아동을대상으로 Baddeley (1986, 2000) 가제시한작업기억의세가지하위체계중언어적요소가관여하는두체계인음운루프 (phonological loop), 임시완충기 (episodic buffer) 를측정하는비단어따라말하기과제와문장따라말하기과제의채점방식에따른진단적정확도를검토해보고자한다. 또한, 비언어적요소가관여하는시공간스케치패드 (visuospatial sketchpad) 를측정하는매트릭스과제의수행조건에따라어휘발달지체아동과일반아동이얼마나정확하게구분되는지를검토해보고자한다. 연구방법연구대상본연구는서울및경기지역에거주하는생활연령 5-6세의어휘발달지체 (VD) 아동 40명 ( 남아 23, 여아 17), 그리고이아동들과생활연령및성별을일치시킨일반아동 (NL) 40명 ( 남아 23, 여아 17) 을대상으로하였다. 모든아동들은 (1) 카우프만아동용지능검사 (Korean Kaufman Assessment Battery for Children, K-ABC; Moon & Byun, 2003) 의비언어성지능지수가 85 (-1 SD) 이상이고, (2) 주 488

5 채점단위및수행조건에따른작업기억과제의언어장애진단정확도비교연구 임동선외 Table 1. Participants characteristics by subgroup 양육자또는어린이집및유치원교사에의해정서및감각 ( 시각, 청 각 ), 기타신경학적결함이없으며인지및신체기능이정상범주인 것으로보고된아동으로선정하였다. 대상아동들의평균생활연 령은 개월 (SD = 3.92), 비언어성지능지수의평균은 (SD = 9.18) 로나타났다. 연구에참여한아동들은공식언어검사인수용및표현어휘력 검사 (Receptive & Expressive Vocabulary Test; Kim, Hong, Kim, Jang, & Lee, 2009) 수행력에따라수용어휘력또는표현어휘력점 수가또래대비 10%ile 미만인경우어휘발달지체아동집단으로, 수용어휘력및표현어휘력점수가모두또래대비 10%ile 보다높은 경우일반아동집단으로선정되었다. 각집단의생활연령, 비언어 성지능지수, 수용및표현어휘력점수의평균및표준편차는 Table 1 에제시하였다. 독립표본 t- 검정으로집단간차이를검증한결과, 수용어휘력 (t(78) = 8.601, p<.001) 및표현어휘력 (t(78) = 6.909, p<.001) 이모 두유의한차이가있는것으로나타났으며, 생활연령과비언어성 지능지수는통계적으로유의한차이가없었다. 과제실시방법 비단어따라말하기 VD (N = 40) NL (N = 40) Age (mo) 70.9 (3.92) (3.97) Nonverbal IQ a 104 (10.42) (7.48) Receptive vocabulary b 50.7 (8.13) 68.2 (9.98) Expressive vocabulary b 60.3 (10.41) (9.2) Values are presented as mean (SD). VD = children with vocabulary delay; NL = children with normal language. a Korean Kaufman Assessment Battery for Children (Moon & Byun, 2003), b Receptive & Expressive Vocabulary Test (Kim, Hong, Kim, Jang, & Lee, 2010). 아동의음운작업기억능력을측정하기위하여비단어따라말하 기과제 (Lee, Yim, & Sim, 2012; Oh & Yim, 2013) 를사용하였다. 과 제의문항은 2 음절, 3 음절, 4 음절, 5 음절, 6 음절이각 4 개씩, 총 20 개의비단어목록으로구성되었으며, 과제의타당도평가를위해 언어병리학석사학위소지자 2 명에게해당 20 개비단어목록의단 어유사성 (wordlikeness) 을평가하게하였다. 5 점척도 (1 점 전혀유 사하지않다, 2 점 유사하지않다, 3 점 보통이다, 4 점 유사하다, 5 점 매우유사하다 ) 로내용타당도를평가한결과, 평균 1.02 점으로 과제문항의단어유사성이낮은것으로나타났다. 검사자는아동 에게비단어문항이녹음된파일을헤드폰없이컴퓨터로들려주 고, 앵무새처럼똑같이따라말하게지시하여과제를수행하도록 하였다. 문항을들려주는동안컴퓨터화면에는음성파일의재생화면만이제시되었으며, 조용한방에서아동과검사자가일대일로검사를진행하였다. 검사자는연습문제를통하여아동이검사의수행방법을숙지했다고판단이되면검사를진행하였으며, 아동의반응을듣고즉각적으로정오를판단하면서전사하였다. 아동의반응은녹음기로녹취하여검사종료후재확인하였다. 비단어따라말하기과제는두가지방식으로채점되었는데, 낱말단위의채점방식은제시문항에서음절길이에관계없이비단어를정확하게따라말할경우 1점으로처리하고, 음소를하나라도부정확하게따라말할경우 0점으로처리하였다 (Tattersall, Nelson, & Tyler, 2015). 이채점방식에서는총 20문항의낱말수의총합이총점으로, 최고점수는 20점이된다. 음절단위의채점방식은제시문항에서아동이산출한구어반응이정확하고위치도일치하는경우정반응으로처리하였으며, 정확하게따라말한음절의총합을측정하였다 (Oh & Yim, 2013; Yim, Kim, et al., 2016). 선행연구를참고하여정확한발음과경미한왜곡은정반응으로, 음절내의음소의생략과대치, 첨가는오류로처리하였다 (Dollaghan & Campbell, 1998; Oh & Yim, 2013). 총 20문항의총음절수는 80음절로, 이채점방식에서최고점수는 80점이된다. 원점수로총점을계산한후, 과제간수행력비교의편의를위하여정반응률도함께계산하여기록하였다. 문장따라말하기아동의임시완충기 (episodic buffer) 능력을측정하기위하여문장따라말하기과제 (Ahn & Kim, 2000; Oh & Yim, 2013; Park et al., 2014) 를일부수정하여사용하였다. 본과제는문장길이와문장구조에따라난이도가구분되어 3어절단문, 5어절단문, 5어절접속문각 9개씩, 5어절내포문 8개, 총 35개의문장으로구성되었다. 검사자는아동에게앵무새처럼똑같이따라말하기를지시하며과제수행방법을설명하면서연습문항을실시한후, 아동이검사내용을숙지했다고판단이되면검사를진행하였다. 검사문항은사전에음성파일로녹음되어헤드폰없이컴퓨터로제시되었으며, 검사자는아동의반응을즉각적으로정오판단하면서전사하였다. 문항이제시되는동안컴퓨터화면에는음성파일의재생화면만이보여졌으며, 조용한방에서아동과검사자가일대일로검사를진행하였다. 아동의반응은녹음기로녹취하여검사종료후재확인하였다. 문장따라말하기과제는비단어따라말하기과제와마찬가지로두가지방식으로채점되었는데, 문장단위채점방식은문장전체를오류없이정확하게따라말한경우 1점, 문장의어느한부분이 489

6 Dongsun Yim, et al. Diagnostic Accuracy of Working Memory Tasks 라도정확하게따라말하지못한경우 0점으로처리하였다 (Kim & Chung, 2011; Hwang, 2012; Lee et al., 2014). 제시문항은총 35문항으로이채점방식에서최고점수는 35점이된다. 검사자는아동이정확하게따라말한문장수의총점을기록하고정반응률을계산하였다. 어절단위채점방식은문항별로각각 3어절문장은 3점만점에서오류가나타난어절의횟수만큼제하였고, 5어절문장은 5점만점에서오류어절의횟수를제하는방식으로처리하였다 (Stokes, Wong, Fletcher, & Leonard, 2006; Park et al., 2014). 본과제에서제시문항은총 35문항으로총어절수는 157어절, 최고점수는 157점이된다. 아동이정확하게따라말한어절수의총점을기록하고정반응률도함께계산하여기록하였다. 매트릭스비언어적작업기억인시공간스케치패드 (visuospatial sketchpad) 를측정하는과제로매트릭스과제를사용하였다. 본연구에서사용된과제 (Yim et al., 2015) 는선행연구 (Gathercole & Pickering, 2000) 에서사용한역동적매트릭스과제 (dynamic matrices test) 를수정 보완하여사용한과제로, 3 3 총 9개의정사각형으로구성된매트릭스에불이깜빡이는순서를기억하여회상하는과제이다. 먼저컴퓨터화면중앙에동일한크기로분할된 3 3 매트릭스가제시된이후, 0.5초의간격으로 9개매트릭스중한칸에주황색불이 1초동안점등된다. 정지화면이나타난후, 처음에제시되었던 9개의빈매트릭스가나타나면, 아동은불이들어왔던칸의순서를기억하여손가락으로가리키면서반응한다. 본과제는매트릭스에점등되는순서를그대로 (forward) 기억하는방식과, 역순으로 (backward) 기억하는두가지방식으로진행되었다. 총검사문항수는연습문항 5개와본문항 18개이며, 난이도 1은점등하는칸이 2개 (span-2), 난이도 2는점등하는칸이 3개 (span- 3), 난이도 3은 4개 (span-4), 난이도 4는 5개 (span-5) 로각단계별로회상해야하는칸의개수가하나씩늘어난다. 각난이도별검사문항수는난이도 1과 2는 4문항, 난이도 3과 4는 5문항으로구성되었다. 연습문항을실시하여아동이검사방법을충분히숙지했다고판단한이후에검사문항을실시하였다. 과제의점수는정반응은 1 점, 오반응은 0점으로기록하였으며, 원점수로총점을계산한후정반응률도함께기록하였다. 자료분석방법본연구의모든통계분석은 SPSS ver. 23.0을사용하였다. 본연구에서는각과제별로두가지분석을실시하였는데, 우선세가지작업기억과제의집단간차이를검증하기위하여비단어따라말하 기과제및문장따라말하기과제는채점단위별로, 그리고매트릭스과제는수행조건별로독립표본 t-검정을실시하였다. 그리고각과제별채점단위또는수행조건에따른언어발달지체에대한진단정확도를측정하기위하여판별분석 (discriminant analysis) 을실시하였으며, 이에따라각과제의민감도 (sensitivity), 특이도 (specificity), 통합정확도 (overall classification), 양성우도비 (positive likelihood ratio), 음성우도비 (negative likelihood ratio) 를산출하였다. 민감도는실제장애가있는사람들중장애로진단되는정확도, 특이도는실제장애가없는사람들중비장애로진단되는정확도이며, 통합정확도는전체대상자중장애와비장애로바르게진단되는해당검사의정확도를가리킨다 (Hwang, 2012; Lugo-Neris, Peña, Bedore, & Gillam, 2015). 민감도와특이도는해당장애의유병률 (prevalence) 에영향을받는다는한계가있는데, 우도비 (likelihood ratio) 는유병률에영향받지않는값으로서해당검사의진단정확도를나타낸다. 우도비는민감도와특이도로부터산출할수있는데, 양성우도비는민감도 /(1- 특이도 ), 음성우도비는 (1-민감도)/ 특이도의값으로구해진다 (Archibald & Joanisse, 2009). 또한평가자간신뢰도를측정하기위하여전체자료중 10% 를임의로선정하여언어병리학과박사과정에재학중인연구원 1명이재측정하여상관관계를분석하였다. 그결과피어슨상관계수가비단어따라말하기과제는.921 (p<.05), 문장따라말하기과제는.892 (p<.05), 매트릭스과제는.997 (p<.01) 로유의하게높은상관관계를보였다. 연구결과언어적작업기억과제의집단간차이검증및판별분석결과언어적작업기억과제의집단간차이검증어휘발달지체아동집단및일반아동집단의비단어따라말하기, 문장따라말하기과제의수행력에대한기술통계결과는 Table 2와같다. 각과제는채점단위에따라수행력을제시하였다. 독립표본 t-검정으로집단간과제수행력차이를검증한결과, 비단어따라말하기과제의경우낱말단위채점방식 (t(78) = 2.429, p<.05) 및음절단위채점방식 (t(78) = 2.228, p<.05) 모두집단간차이가통계적으로유의하였으며, 문장따라말하기과제도마찬가지로문장단위채점방식 (t(61.417) = 4.400, p<.001) 및어절단위채점방식 (t(74.690) = 2.625, p<.05) 모두집단간차이가통계적으로유의하였다. 집단간평균차이를통합표준편차 (pooled standard deviation) 로나눈값인 Cohen s d로효과크기를추정하였으며, Cohen s d값은비단어따라말하기 ( 낱말단위 ) 는.543, 비단어따라 490

7 채점단위및수행조건에따른작업기억과제의언어장애진단정확도비교연구 임동선외 말하기 ( 음절단위 ) 는.498, 문장따라말하기 ( 문장단위 ) 는.984, 문장따라말하기 ( 어절단위 ) 는.587로나타났다. 언어적작업기억과제의판별분석결과비단어따라말하기및문장따라말하기과제의채점방식에따른어휘발달지체진단정확도를분석하기위하여판별분석을실시하였으며, 그결과는 Table 3에제시하였다. 판별분석결과, 비단어따라말하기과제의경우특이도는두가지채점방식에서동일하게나타났으나민감도가낱말단위채점방식 (65%) 이음절단위채점방식 (52%) 에비해높았으며, 따라서통합정확도는낱말단위채점방식이 67.5% 로음절단위채점방식 (61.3%) 보다높게나타났다. 문장따라말하기과제의경우는특이도는어절단위채점방식 (87.5%) 이문장단위채점방식 (77.5%) 에비해높았으나, 민감도는문장단위채점방식 (60%) 이어절단위채점방식 (45%) 에비해높았다. 통합정확도는문장단위채점방식 (68.8%) 이어절단위채점방식 (66.3) 에비해높은것으로나타났다. 우도비는비단어따라말하기과제의낱말단위채점방식의 LR+ 는 2.16, LR-는 0.5로, 음절단위채점방식의 LR+ 는 1.73, LR-는 0.69로나타났다. 문장따 라말하기과제의경우낱말단위채점방식의 LR+ 는 3.6, LR-는 0.63 으로, 문장단위채점방식의 LR+ 는 2.67, LR-는 0.51로나타났다. 또한과제조합의판별력을검토하기위하여비단어따라말하기과제와문장따라말하기과제의채점방식을조합하여판별분석을실시하였다. 그결과, 비단어따라말하기 ( 음절단위 )+ 문장따라말하기 ( 어절단위 ) 를제외한나머지세조합의민감도 (77.5%) 와특이도 (60%), 그에따른통합정확도 (68.8%) 가모두동일한것으로나타났다. 비언어적작업기억과제의집단간차이검증및판별분석결과비언어적작업기억과제의집단간차이검증어휘발달지체아동집단및일반아동집단의매트릭스과제의검사수행조건에따른수행력에대한기술통계결과는 Table 4와같다. 독립표본 t-검정으로집단간과제수행력차이를검증한결과, 순서대로회상하는방법 (t(78) =.334, p=.148) 및역순으로회상하는방법 (t(78) =1.074, p=.286) 두가지모두집단간차이가통계적으로유의하지않았다. Table 2. Descriptive statistics on verbal working memory tasks by groups Task NWR SR Accuracy (%) VD (N = 40) NL (N = 40) Word (14.41) (15.49) Syllable (7.86) (9.15) Sentence (22.12) (12.43) Word (14.01) (11.31) Values are presented as mean (SD). VD = children with vocabulary delay; NL = children with normal language; NWR = nonword repetition; SR= sentence repetition. 비언어적작업기억과제의판별분석결과 매트릭스과제의수행조건에따른어휘발달지체진단정확도를 Table 4. Descriptive statistics on nonverbal working memory tasks by groups Task MATRIX Accuracy (%) VD (N = 40) NL (N = 40) Forward (20.50) (16.84) Backward (16.88) (20.06) Values are presented as mean (SD). VD= children with vocabulary delay; NL= children with normal language. Table 3. Discriminant functions in verbal working memory Discriminant function Overall classification Sensitivity Specificity LR+ LR- Wilks s λ χ 2 Canonical correlation NWR_word NWR_syllable SR_sentence <.001 SR_word NWR_word + SR_sentence <.001 NWR_word + SR_word NWR_syllable + SR_sentence <.001 NWR_syllable + SR_word LR+ = positive likelihood ratio; LR- = negative likelihood ratio; NWR = nonword repetition; SR = sentence repetition; NWR_word = NWR task with a word unit in scoring; NWR_syllable = NWR task with a syllable unit in scoring; SR_sentence = SR task with a sentence unit in scoring; SR_word = SR task with a word unit in scoring. p-value 491

8 Dongsun Yim, et al. Diagnostic Accuracy of Working Memory Tasks Table 5. Discriminant functions in nonverbal working memory Discriminant function Overall classification Sensitivity Specificity LR+ LR- Wilks s λ χ 2 Canonical correlation MATRIX_F >.05 MATRIX_B >.05 LR+= positive likelihood ratio; LR- = negative likelihood ratio; MATRIX_F= matrix forward task; Matrix_B = matrix backward task. p-value 분석하기위하여판별분석을실시하였으며, 그결과는 Table 5에제시하였다. 판별분석결과, 매트릭스과제의경우두가지수행조건모두판별함수가통계적으로유의하지않은것으로나타났다. 논의및결론본연구는언어장애아동을진단하는데있어임상및연구에서다양한방식으로사용되고있는작업기억과제들의진단정확도를비교검증하기위하여언어적작업기억을측정하는과제인비단어따라말하기과제와문장따라말하기과제의채점방식에따른진단정확도를비교하고, 비언어적작업기억을측정하는매트릭스과제의순행및역행방식의진단정확도를검토하고자하였다. 이를위하여어휘발달지체아동집단및일반아동집단을대상으로작업기억의하위영역인음운루프, 임시완충기, 시공간스케치패드를측정하는각과제 ( 비단어따라말하기, 문장따라말하기, 매트릭스 ) 의수행력을비교한후판별분석을실시하였다. 본연구에서는비단어따라말하기과제의경우낱말단위및음절단위의두가지채점방식으로어휘발달치제아동과일반아동을대상으로그수행력을분석하였는데, 두가지채점방식에서모두집단간차이가유의한것으로나타났다. 두가지채점방식의특이도에는차이가없었으나, 낱말단위채점방식의민감도가음절단위채점방식보다높아민감도와특이도를모두고려한진단정확도는낱말단위채점방식이더높은것으로나타났다. 또한양성우도비와음성우도비의의미를고려하였을때, 양성우도비가높을수록, 음성우도비가낮을수록진단정확도가높음을알수있는데, 본연구에서는낱말단위채점방식이음절단위채점방식에비해양성우도비가더높고음성우도비가더낮은것으로나타났다. 즉, 낱말단위채점방식이장애군을장애로진단하고비장애군을비장애로배제시킬수있는가능성이높은것으로나타났다. 또한 Cohen s d 값으로측정한효과크기도낱말단위채점방식 (Cohen s d=.543) 이음절단위채점방식 (Cohen s d=.493) 보다높은것으로나타나판별분석결과를지지해주었다. 5세아동을대상으로낱말단위채점방식을사용한비단어따라말하기과제에대한판별분석을실시 한선행연구 (Conti-Ramsden & Hesketh, 2003) 에서는민감도가 59%-66%, 특이도가 85%-89% 로나타났다. 해당선행연구에서는특히비단어따라말하기과제수행력이백분위수 25 미만인아동이단순언어장애로진단될가능성이높음을밝힘으로써, 비단어따라말하기과제의선별도구로서의유용성을다시한번확인하였다. Conti-Ramsden과 Hesketh (2003) 의연구와비슷한연령의아동을대상으로한본연구에서는낱말단위채점방식의경우민감도가 65%, 특이도가 70% 로, 해당선행연구에비해특이도는낮았으나민감도는비슷한수준인것으로나타났다. 따라서본연구에서사용한비단어따라말하기과제의임상적유용성을집단간차이검증을통해확인함과동시에, 선행연구와비교하였을때에도본연구에서사용된과제의경우시간적효율성이높은낱말단위채점방식이언어발달지체를선별해내는진단정확도도높음을확인하였다. 문장따라말하기과제의경우문장단위채점방식과어절단위채점방식의수행력을분석하였는데, 민감도는문장단위채점방식이높았으며특이도는어절단위채점방식이높았다. 민감도와특이도를함께고려한통합정확도는문장단위채점방식이높은것으로나타났다. 우도비를고려하였을때에는양성우도비의경우어절단위채점방식이더높았으며음성우도비는문장단위채점방식에서더낮은것으로나타나민감도및특이도분석결과와상반되는결과를보였다. 즉, 실제장애가있는사람들중장애로진단되는비율인민감도는문장단위채점방식이높았으나, 검사결과가해당장애가있다고말할수있는임상적정확도는어절단위채점방식이더높은것으로나타났으며, 실제장애가없는사람들중비장애로진단되는비율인특이도와검사결과가해당장애가없다고배제할수있는임상적정확도간의관계도상반되게나타났음을의미한다. 이는우도비의계산방식을고려해보았을때, 어절단위채점방식의민감도가 50% 미만의낮은값을가졌으며특이도는 87.5% 로가장높게나타나, 어절단위채점방식에서민감도와특이도의격차가커진것에서비롯되었음을알수있다. 즉, 양성우도비를산출할때 (1- 특이도 ) 의값으로계산되는분모값이작아지는폭이커짐으로써민감도가작아지는폭을상쇄하였으며, 음성우도비를산출할때에는 (1-민감도) 의값으로계산되는분자값의증가폭이분모값 492

9 채점단위및수행조건에따른작업기억과제의언어장애진단정확도비교연구 임동선외 인특이도가작아지는폭을상쇄하여민감도와특이도, 우도비간상충되는결과를나타낸것으로보인다. 민감도와특이도의경우 Plante와 Vance (1994) 등은 80% 를최소한의기준으로제시하고는있으나, 일반적으로통용되는규준은없다고할수있다. 그러나어절단위채점방식은민감도가 50% 미만으로낮게나타났으며, 문장단위채점방식의경우특이도는어절단위채점방식보다낮은수준이나 80% 에가까운정도이고민감도및통합정확도가높게나타나본연구에서진단의정확도가더욱우수한수준인것으로판단할수있다. 이는문장단위채점방식이언어장애를진단하는데더욱정확한정보를제공했음을밝힌선행연구 (Leclercq, Quemart, Magis, & Maillart, 2014; Hwang, 2012; Park et al., 2014) 와도일치하는결과라하겠다. Cohen s d값으로측정한효과크기는문장단위채점방식이 0.984, 어절단위채점방식이 0.587로, 문장단위채점방식의경우 Cohen (1992) 의기준에의할때매우높은수준인것으로나타나, 선행연구결과를지지하였다. 즉, 본연구에서사용된문장따라말하기과제가어휘발달지체집단을유의하게구별해주며, 특히문장단위채점방식이집단을구분하는임상적정확도가높은것으로나타났다. 매트릭스과제의경우두가지과제수행조건에서모두집단간차이가통계적으로유의하지않았으며, 판별분석결과또한유의하지않았다. 이는두가지가능성으로해석할수있을것으로보인다. 첫째, 연구대상아동들의비언어적작업기억을측정하는과제인매트릭스는 9개정사각형매트릭스에점멸하는칸을기억했다가순서대로또는역순으로회상하여반응하는과제인데, 본연구에서사용된매트릭스과제는 2개칸이점멸하는 span-2가 4개항목, span-3이 4개항목, span-4가 5개, span-5 가 5개항목으로구성되었다. 두집단모두순서대로회상하는방식에서정반응률이 60% 에미치지못하였으며, 이는대부분의아동들이 span-4에서정반응률이급격히낮아졌음을의미한다. 역순으로회상하는방식에서는두집단모두정반응률이 50% 에미치지못하였다. 본연구에서사용된비단어따라말하기과제의정반응률이어휘발달지체아동집단은 62.88%, 일반아동집단은 71% 임을고려해볼때언어적작업기억과제의경우두집단모두평균적으로 span-4의수행률을보였으며, 5-6세아동을대상으로한선행연구 (Jones, Tamburelli, Watson, Gobet, & Pine, 2010) 에서비단어따라말하기과제수행력의최대치를 span-5로제시한것과는대조적이다. 본연구의결과로비언어적작업기억은언어적작업기억과다른부하 (load) 와기억폭 (span) 을가짐을추측해볼수있다. 이는다양한작업기억과제들을대상으로요인분석을실시한국내의선행연구 (Yim et al., 2015) 에서매트릭스과제가복합처리또는다중처리작업기억과제 로분류된것에서도확인할수있다. 즉, 비언어적작업기억과제인매트릭스과제는학령전기의두집단아동모두에게과제를수행하는데있어보다높은수준의처리부하 (load) 를요구함으로써집단간변별력이낮게나타났을가능성이있다. 또다른가능성으로는어휘발달지체아동의비언어적작업기억이언어적작업기억에비해비교적손상되지않았을가능성을검토해볼수있다. 단순언어장애아동을대상으로한선행연구 (Alt, 2013; Ricco, Cash, & Cohen, 2007) 에의하면비언어적작업기억과제의수행력이또래일반아동과통계적으로유의한차이가나타나지않았으며, 이러한연구결과는단순언어장애아동이비언어적정보를순간적으로유지하고조작및처리하는능력은언어적정보를조작하는것과달리또래와크게다르지않을것임을의미한다. 비언어적작업기억과제의어휘발달지체아동에대한판별력이낮게나타난본연구의결과는작업기억의하위체계들간의관계에있어서영역-일반적인 (domain-general) 작업기억을강조하는입장 (Engle, Tuholski, Laughlin, & Conway, 1999; Kane et al., 2004) 보다는영역-특정적인 (domain-specific) 작업기억을강조하는선행연구들 (Miyake, Friedman, Rettinger, Shah, & Hegarty, 2001; Shah & Miyake, 1996) 을지지하는결과라고할수있다. 본연구는 5-6세어휘발달지체아동및일반아동을대상으로 Baddeley가제안한작업기억의하위체계인음운루프, 임시완충기, 시공간스케치패드를측정하는세가지과제들의채점단위및과제수행조건에대한진단정확도를검토하였다. 음운루프를측정하는비단어따라말하기과제및임시완충기를측정하는문장따라말하기과제에서는집단차이검증및판별분석에서모두통계적으로유의한결과가도출되었으나, 시공간스케치패드를측정하는매트릭스과제에서는그렇지않았다. 그원인으로영역-특정적인작업기억이론에기반하여비언어적작업기억능력이언어적작업기억능력에비해비교적손상되지않았을가능성을제시하였으나, 과제난이도조절의실패를또다른원인으로지적할수있을것이다. 다시말해, 본과제에서사용한매트릭스과제가 5-6세아동들에게지나치게어려워과제의변별력이저하되었을가능성이있다. 따라서후속연구에서는해당과제를고연령층의아동들에게확대실시하여매트릭스과제의두가지수행조건중어느것이더집단을명확히구분해줄수있을지검증할필요가있다. 또한본연구는어휘발달지체아동으로대상군을제한한점과, 기억폭과제인세가지과제모두조건을폭의범위별로세분화하여정밀하게측정하지못한한계점이있다. 그러나많은선행연구들에서이미임상적으로유용성이인정된비단어따라말하기, 문장따라말하기과제의채점단위간직접적인비교를통하여연구및임상에서의효용성을제 493

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13 채점단위및수행조건에따른작업기억과제의언어장애진단정확도비교연구 임동선외 ing Research, 49, Storch, S. A., & Whitehurst, G. J. (2002). Oral language and code-related precursors to reading: evidence from a longitudinal structural model. Developmental Psychology, 38, Tattersall, P. J., Nelson, N. W., & Tyler, A. A. (2015a). A pilot study comparing two nonword repetition tasks for use in a formal test battery. Communication Disorders Quarterly, 36, Tattersall, P. J., Nelson, N. W., & Tyler, A. A. (2015b). Associations among nonword repetition and phonemic and vocabulary awareness: implications for intervention. Child Language Teaching and Therapy, 31, Tyler, A. A., & Tolbert, L. C. (2002). Speech-language assessment in the clinical setting. American Journal of Speech-Language Pathology, 11, Vandierendonck, A., & Szmalec, A. (2004). An asymmetry in the visuo-spatial demands of forward and backward recall in the Corsi blocks task. Imagination, Cognition and Personality, 23, Wagner, R. K., Torgesen, J. K., Rashotte, C. A., & Pearson, N. A. (2013). CTOPP-2: Comprehensive test of phonological processing. Austin, TX: Pro-Ed. Walker, D., Greenwood, C., Hart, B., & Carta, J. (1994). Prediction of school outcomes based on early language production and socioeconomic factors. Child Development, 65, Wechsler, D. (1989). Wechsler Preschool and Primary Intelligence Scale-Revised. San Antonio, TX: Psychological Corporation. Windsor, J., Kohnert, K., Lobitz, K. F., & Pham, G. T. (2010). Cross-language nonword repetition by bilingual and monolingual children. American Journal of Speech-Language Pathology, 19, Yang, Y., Yim, D., Kim, S., & Han, J. (2013). The relationship among receptive vocabulary, non-word repetition, and quick incidental learning in preschoolers with and without delay in vocabulary development. Communication Sciences & Disorders, 18, Yim, D. (2017). Common versus unique findings on processing-based task performance in Korean speaking children with cochlear implants. Otology & Neurotology, 38, Yim, D., Jo, Y., Han, J., & Sung, J. (2016) Executive function in Korean-English bilingual children with and without vocabulary delay. Communication Sciences & Disorders, 21, Yim, D., Kim, S., & Yang, Y. (2015). Factor analysis of working memory tasks based on information processing characteristics: Predictive factors of receptive vocabulary and quick incidental learning in children with typically developing and receptive vocabulary delay. Communication Sciences & Disorders, 20, Yim, D., Kim, Y., & Yang, Y. (2016). Exploring the utility of verbal and visuospatial working memory for identifying children with language impairment. Communication Sciences & Disorders, 21,

14 Dongsun Yim, et al. Diagnostic Accuracy of Working Memory Tasks 국문초록 채점단위및수행조건에따른작업기억과제의언어장애진단정확도비교연구임동선 김신영 유지원 이윤정 이상언 정하은 이화여자대학교대학원언어병리학과배경및목적 : 비단어따라말하기, 문장따라말하기, 매트릭스는언어능력의기저요인으로주목받아온작업기억의각하위체계를평가하기위한과제로, 많은선행연구들과임상에서사용되어왔다. 그러나각과제의채점단위또는수행조건이일치되지않아왔던바, 본연구에서는각과제별로언어장애를보다정확하고효과적으로판별할수있는방식을재검토하고정확한시행방법을제시하고자한다. 방법 : 본연구는 5-6세의어휘발달지체아동 (N= 40) 과일반아동 (N= 40) 을대상으로비단어따라말하기및문장따라말하기의채점단위및매트릭스과제의수행조건에따른진단정확도를민감도, 특이도, 양성우도비및음성우도비를통하여분석하였다. 결과 : 판별분석결과, 비단어따라말하기과제는음절단위채점방식에비해낱말단위채점방식이, 문장따라말하기과제는어절단위채점방식에비해문장단위채점방식의진단정확도가더욱높은것으로나타났다. 매트릭스과제는집단간수행력차이와판별분석결과가순행및역행조건모두에서유의하지않았다. 논의및결론 : 비단어따라말하기과제및문장따라말하기과제는시간적효율성이높은채점방식이진단정확도도높은것으로나타나그임상적효용성을입증하였다. 핵심어 : 비단어따라말하기, 문장따라말하기, 매트릭스, 진단정확도, 판별분석, 작업기억 참고문헌 강은희, 강대옥 (2016). 학령전단순언어장애아동의비단어따라말하기와문장따라말하기수행능력특성. 특수교육재활과학연구, 55, 김동일 (2011). 기초학습기능수행평가체제 : 초기문해. 서울 : 학지사심리검사연구소. 김애화, 김의정, 황민아, 유현실 (2014). 읽기성취및읽기인지처리능력검사 (RA-RCP). 서울 : 학지사. 김영태 (2014). 아동언어장애의진단및치료. 서울 : 학지사. 김영태, 박소현, 이희란 (2005). 학령전언어장애아동진단모델정립을위한질적연구. 언어청각장애연구, 10, 김영태, 성태제, 이윤경 (2003). 취학전아동의수용언어및표현언어발달척도 (PRES). 서울 : 서울장애인종합복지관. 김영태, 홍경훈, 김경희, 장혜성, 이주연 (2009). 수용 표현어휘력검사 (REVT). 서울 : 서울장애인종합복지관. 김정숙, 정승문 (2011). 문장의길이와구조에따른 3-5 세아동의문장따라말하기수행력. 언어치료연구, 20, 문수백, 변창진 (2003). 한국카우프만아동지능검사 (K-ABC). 서울 : 학지사. 박원정, 윤사라, 한보연, 임동선 (2014). 한국어문장따라말하기검사의점수체계비교연구. 언어치료연구, 23, 배소영, 김미배, 윤효진, 장승민 (2015). 한국어읽기검사 (KOLRA). 서울 : 학지사. 안지숙, 김영태 (2000). 단순언어장애아동과정상아동의구문적난이도에따른문장따라말하기 : 수행력및명료도비교. 음성과학, 7, 양윤희, 임동선, 김신영, 한지윤 (2013). 학령전어휘발달지체및일반아동의비단어따라말하기, 빠른우연학습 (Quick Incidental Learning) 과수용어휘와의관계. 언어청각장애연구, 18, 오다연, 임동선 (2013). 2-3세말늦은아동과정상아동의비단어따라말하기와문장따라말하기수행능력. 언어청각장애연구, 18, 이윤경. (2006). 학령기아동언어장애진단및평가에관한질적연구 : 진단및평가모형정립을위한기초연구. 언어청각장애연구, 11, 이은주. (2010). 국외화용언어평가도구분석. 언어치료연구, 19, 이정미, 최소영, 황민아 (2014). 문장따라말하기에서나타난단순언어장애아동의조사처리능력. 언어청각장애연구, 19, 임동선, 김신영, 양윤희 (2015). 정보처리특성에따른작업기억과제의탐색적요인분석. 언어청각장애연구, 20, 임동선, 김영태, 양윤희 (2016). 언어장애아동판별을위한구어및시공간적작업기억의효용성탐색. 언어청각장애연구, 21,

15 채점단위및수행조건에따른작업기억과제의언어장애진단정확도비교연구 임동선외 임동선, 조연주, 한지윤, 성지민 (2016). 한국어-영어이중언어사용아동의어휘발달지연유무에따른집행기능비교. 언어청각장애연구, 21, 홍성미, 임동선 (2014). 학습및기억과제를통한이중언어아동의언어발달지체평가. 언어청각장애연구, 19, 황민아 (2003). 단순언어장애아동의문장이해 : 단서이용양상을중심으로. 언어청각장애연구, 8, 황민아 (2012). 문장따라말하기검사의학령전단순언어장애진단정확도. 언어청각장애연구, 17, 황민아 (2014). 읽기이해부진아동의작업기억특성 : 문장따라말하기및비단어따라말하기검사중심으로. 학습장애연구, 11,