Sophia van Hees a b, Anthony Angwin b, Katie McMahon c & David Copland a b d a Centre for Clinical Research, University of

Transcription

1 This article was downloaded by: [UQ Library] On: 17 February 2015, At: 18:47 Publisher: Routledge Informa Ltd Registered in England and Wales Registered Number: Registered office: Mortimer House, Mortimer Street, London W1T 3JH, UK Neuropsychological Rehabilitation: An International Journal Publication details, including instructions for authors and subscription information: A comparison of semantic feature analysis and phonological components analysis for the treatment of naming impairments in aphasia Sophia van Hees a b, Anthony Angwin b, Katie McMahon c & David Copland a b d a Centre for Clinical Research, University of Queensland, Brisbane, Australia b School of Health and Rehabilitation Sciences, University of Queensland, Brisbane, Australia c Centre for Advanced Imaging, University of Queensland, Brisbane, Australia d Clinical Centre for Research Excellence in Aphasia Rehabilitation, University of Queensland, Brisbane, Australia Published online: 26 Oct To cite this article: Sophia van Hees, Anthony Angwin, Katie McMahon & David Copland (2013) A comparison of semantic feature analysis and phonological components analysis for the treatment of naming impairments in aphasia, Neuropsychological Rehabilitation: An International Journal, 23:1, , DOI: / To link to this article: PLEASE SCROLL DOWN FOR ARTICLE

2 Taylor & Francis makes every effort to ensure the accuracy of all the information (the Content ) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sublicensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at

3 NEUROPSYCHOLOGICAL REHABILITATION, 2013 Vol. 23, No. 1, , A comparison of semantic feature analysis and phonological components analysis for the treatment of naming impairments in aphasia Sophia van Hees 1,2, Anthony Angwin 2, Katie McMahon 3, and David Copland 1,2,4 1 Centre for Clinical Research, University of Queensland, Brisbane, Australia 2 School of Health and Rehabilitation Sciences, University of Queensland, Brisbane, Australia 3 Centre for Advanced Imaging, University of Queensland, Brisbane, Australia 4 Clinical Centre for Research Excellence in Aphasia Rehabilitation, University of Queensland, Brisbane, Australia Therapy for naming impairments post-stroke typically involves semantic and/ or phonologically-based tasks. However, the relationship between individuals locus of breakdown in word retrieval and their response to a particular treatment approach remains unclear, and direct comparisons of treatments with different targets (semantics, phonology) yet similar formats are lacking. This study examined eight people with aphasia who each received 12 treatment sessions; half the sessions involved a semantically-based treatment task, Semantic Feature Analysis (SFA), and the other half involved a phonologically-based treatment task, Phonological Components Analysis (PCA). Pre-therapy baseline accuracy scores were compared to naming accuracy post-treatment and at follow-up assessment. Seven of the eight participants showed significant improvements in naming items treated with PCA, with six of these seven participants maintaining improvements at follow-up. Four of the eight participants Correspondence should be addressed to Sophia van Hees, University of Queensland, Centre for Clinical Research, Level 3 Building 71/918, Royal Brisbane and Women s Hospital, Herston QLD 4029, Australia. s.vanhees@uq.edu.au We would like to acknowledge the University of Queensland s Aphasia Registry for the recruitment of participants with aphasia, Charlene Pearson for assistance with data collection, and Associate Professor Greig de Zubicaray for assistance with editing the manuscript. # 2013 Taylor & Francis

4 showed significant improvements for items treated with SFA, with three of the four maintaining improvements at follow-up. The semantic therapy was not beneficial for participants with semantic deficits. In contrast, the phonological therapy was beneficial for most participants, despite differences in underlying impairments. Understanding the relationship between an individual s locus of breakdown in word retrieval and response to different treatment tasks has the potential to optimise targeted treatment. Keywords: Anomia; Stroke; Aphasia; Rehabilitation. NAMING TREATMENT IN APHASIA 103 INTRODUCTION Naming impairments are one of the most common and pervasive language difficulties in people with aphasia and are therefore a major focus of therapy in the rehabilitation of language post-stroke (Goodglass & Wingfield, 1997). Although models of word production differ in terms of the degree of modularity and interactivity between different processing stages, it is well established that naming requires processing at the level of word meaning or semantics, that connects to the word form or phonology (e.g., Dell, Schwartz, Martin, Saffran, & Gagnon, 1997; Goldrick, 2006; Levelt, 1999). People with aphasia may be impaired in one or both of these processing stages, or the connections between them, leading to difficulty naming. Thus, therapy for naming impairments typically employs semantic and/or phonological tasks in order to target these major cognitive components involved in word production. Impaired naming due to semantic deficits may be the result of impaired semantic representations, or difficulty accessing semantic representations (Laine & Martin, 2006). Thus, the rationale underlying semantically-based therapy is that it improves naming by strengthening semantic representations, or by priming weak semantic representations, in order to facilitate word retrieval (Collins & Loftus, 1975; Maher & Raymer, 2004). Semanticallybased therapy tasks that have been shown to improve naming in people with aphasia include spoken and written word picture matching (e.g., Davis & Pring, 1991), semantic feature verification (e.g., Kiran & Thompson, 2003) as well as contextual priming (e.g., Martin, Fink, & Laine, 2004; Renvall, Laine, & Martin, 2007). Improved naming following therapy employing such tasks may be the result of improved processing at the level of the semantic system itself. However, as the word form is also often provided, improvements may not be purely due to changes in semantic processing (Kiran & Bassetto, 2008). In contrast, impaired naming due to deficits in post-semantic/phonological processing may be the result of impaired access to the phonological output

5 104 VAN HEES, ANGWIN, McMAHON, AND COPLAND lexicon, or in the lexical representations themselves (Laine & Martin, 2006). Thus, phonologically-based therapy aims to strengthen representations at the level of the word form (Maher & Raymer, 2004), or strengthen the connections from the semantic system to the word form (Laine & Martin, 2006). Phonologically-based therapy tasks that have been shown to improve naming in people with aphasia include the use of cueing hierarchies and repetition (e.g., Raymer, Thompson, Jacobs, & Le Grand, 1993) as well as tasks such as syllable judgements, initial phoneme discrimination, and rhyme judgement (e.g., Franklin, Buerk, & Howard, 2002; Robson, Marshall, Pring, & Chiat, 1998). Improved naming following the use of such tasks may be the result of improved processing at the level of the phonological form. However, as the corresponding semantic representation becomes activated during word production, and most phonological treatments occur in the presence of a picture, improvements may also be the result of strengthening the mapping between semantics and phonology (Howard, Hickin, Redmond, Clark, & Best, 2006). Studies investigating semantic and phonological therapy for naming impairments have produced varied results. Nettleton and Lesser (1991) compared therapy targeting the impaired process (model appropriate therapy) with therapy targeting a relatively spared process (model inappropriate therapy) in six people with aphasia. Two participants with semantic impairments received semantic therapy, and two participants with impairments in the phonological output lexicon received phonological therapy. The semantic therapy involved word picture matching, categorisation tasks, and yes/no judgements about categorical and attributive information. Thus, the word form was not overtly produced by the participants during the semantic therapy tasks. In contrast, the phonological therapy involved repetition, rhyme judgement, and naming with phonemic cueing. Both participants who received phonological therapy and one participant who received semantic therapy significantly improved in naming of treated items following the therapy, with no generalisation to untreated items. An additional two participants with phonological assembly impairments received the semantic therapy and showed no improvement, which may suggest that therapy targeting the impaired process was more beneficial. However, it was not determined whether the phonological therapy tasks could improve naming in the participants with semantic impairment, or whether the semantic therapy tasks could improve naming in the participants with impairments in the phonological output lexicon. Additionally, one of the participants with semantic impairment did not significantly improve following the semantic therapy. In a larger study conducted by Doesborgh et al. (2004) semantic (BOX) therapy was compared with phonological (FIKS) therapy in a randomised controlled trial with 58 participants with aphasia. The semantic BOX treatment consisted of tasks involving semantic decisions, whereas the

6 NAMING TREATMENT IN APHASIA 105 phonological FIKS treatment involved tasks focusing on sound structure. No significant differences were reported for performance on semantic and phonological tasks pre-treatment in either group. Using the Amsterdam-Nijmegen Everyday Language Test (ANELT; Blomert, 1992), an assessment of verbal communicative ability based on informational content within everyday language scenarios, no difference in improvement post-treatment was found in either the group receiving semantically-based or those receiving phonologically-based therapy. However, the semantic treatment group showed significant improvement on semantic tasks post-treatment (written word synonym judgement and relatedness judgements) and no significant improvement on phonological tasks post-treatment (nonword repetition and auditory lexical decision). The phonological treatment group showed the opposite results, with significant improvements only for the phonological tasks. Such results suggest that although both treatment approaches resulted in improved functional communication, they may have targeted different underlying mechanisms of processing. A limitation of the above studies is that participants did not receive both semantic and phonological treatment, precluding within subject comparisons. This is of particular importance in people with aphasia due to the heterogeneity of language symptoms and variable responses to different treatment tasks, which pose a significant challenge for between-group treatment studies. In an early study conducted by Howard, Patterson, and Franklin (1985), 12 participants with aphasia received both semantic and phonological therapy consisting of word picture matching and semantic verification tasks for the semantic therapy, and repetition, phonemic cueing and rhyme judgement tasks for the phonological therapy. Significant improvements were observed following both treatment types for 8 of the 12 participants, despite variations in locus of breakdown in word retrieval. Davis and Pring (1991) examined the effect of naming therapy involving written word to picture matching compared to repetition of picture names in seven participants with different loci of impairments. Significant improvements were found for both treatments, which were maintained six months post-therapy. Such results suggest that the difference between semantic and phonological therapy tasks may be overstated, and that both approaches may be beneficial for people with different loci of impairments. In contrast, a study conducted by Drew and Thompson (1999) reported that only two of four participants with lexical semantic impairments improved in naming following semantically-based therapy. The other two participants only improved once phonologically-based therapy was added, suggesting that the type of task chosen can determine treatment outcome. However, the type of tasks used to compare semantic and phonological therapy in the above studies varied considerably in terms of format and task demands. Thus, in addition to the language process targeted, the tasks

7 106 VAN HEES, ANGWIN, McMAHON, AND COPLAND may differ with respect to the level of difficulty and the depth of processing required to perform the task, which may also alter the outcome of the treatment. Hickin, Best, Herbert, Howard, and Osborne (2002) suggest that semantic therapy tasks are more likely to involve an element of choice, which may engage a deeper level of processing. For example, picture word matching and semantic relatedness judgements require the person to make a decision, an element often lacking in phonological therapy tasks such as repetition or phonemic cueing. Such differences in task demands may account for the greater and/or longer lasting effects of semantic therapy in previous studies (e.g., Macoir, Routhier, Simard, & Picard, 2012; Marshall, Pound, White-Thomson, & Pring, 1990). Other studies have compared semantic and phonological cueing tasks, which were administered in a similar format and required similar response demands, and may provide a better comparison for treatment outcome. Wambaugh (2003) compared therapy involving semantic versus phonological cueing in a case study of an individual with predominately lexical semantic impairments. Although both cueing techniques resulted in improved naming following therapy, semantic cueing was found to be more effective than phonological cueing. More recently, Lorenz and Ziegler (2009) also compared therapy involving semantic versus phonological cueing in 10 individuals with aphasia. Although one participant with a predominantly semantic impairment only benefited from the semantic cueing therapy, and one participant with a predominantly post-semantic impairment only benefited from the phonological cueing therapy, treatment outcome for the other eight participants did not directly relate to the underlying language deficit. Some participants with semantic impairments benefited from phonological cueing, some participants with post-semantic impairments benefited from semantic cueing, and some participants benefited from both treatments. However, differences were found in the maintenance of improvement between the two therapy tasks; phonological cueing resulted in stronger immediate effects 24 hours post-treatment, whereas semantic cueing was associated with more stable effects at two weeks post-treatment. In order to address the above issues the present study compared the effects of two treatments that target semantics versus phonology although employ a similar format and response demands. Semantic Feature Analysis (SFA) involves analysing the features of an object using a matrix of cue words in order to facilitate the activation of semantic information required for word retrieval (Boyle & Coelho, 1995; Coelho, McHugh, & Boyle, 2000). This task is based on the spreading activation theory of semantic processing (Collins & Loftus, 1975), where activation of the semantic features of a target word is presumed to increase the probability that the target word will reach the threshold needed for activation. It has also been suggested that such a task may increase semantic specificity of the target, and thus aid in

8 NAMING TREATMENT IN APHASIA 107 word retrieval (Nickels, 2002). For example, if categorical errors in naming (e.g., naming an apple as another fruit, such as pear) are due to under-specified semantic information, where multiple lexical representations in a semantic category are equally activated, increasing the activation of distinctive semantic features may increase the probability that the target representation will receive more activation and become selected for further processing. Modelled on the same structure as SFA, Phonological Components Analysis (PCA) was developed as a phonologically-based approach to naming treatment, where the semantic cues in SFA are replaced with cues for phonological features to facilitate processing at the level of the word form (Leonard, Rochon, & Laird, 2008). The depth of processing used in this therapy task has been suggested to promote maintenance of treatment effects, an effect that is variable in the literature concerned with phonological treatment (Hickin et al., 2002). The aim of the current study was to investigate the relative effects of SFA and PCA therapy for naming in a group of people with aphasia. As response to a particular treatment does not always relate to the locus of breakdown in naming, and given the inherent heterogeneity in aphasic symptoms, a within subject alternating treatment design was chosen to allow for comparisons between the different treatments in the same individual. Both treatments were administered in similar formats, where only the type of cue was manipulated, making them comparable. Furthermore, both treatments have shown positive effects previously and were expected to be a similar level of difficulty (e.g., Boyle, 2004; Boyle & Coelho, 1995; Coelho et al., 2000; Leonard et al., 2008). If the semantic and phonological treatment tasks target semantic and phonological processing, respectively, it is predicted that participants with primarily semantic impairments will show greater benefit from the semantically-based therapy, and vice versa participants with primarily phonological impairments will show greater benefit from the phonologically-based therapy. However, if the treatment tasks are not selectively targeting specific levels of processing, no difference is expected between participants with different loci of impairments. METHODS Participants A total of eight people with aphasia (five female), as previously diagnosed by a speech pathologist and according to performance on the Western Aphasia Battery (WAB-R; Kertesz, 2007), participated in the study. Participants ranged in age from 41 to 69 years (mean 56.38; SD 9.15) and were between 17 and 170 months post single left cerebrovascular accident (CVA) at the time of the study (mean 52.25; SD 49.84). See Table 1 for

9 TABLE 1 Demographic information and lesion site for each participant Participant PS JV LW TW HJ TK TP BA Age (years) Months post-stroke Gender F M F F F F M M Years of education NA Lesion volume 22.68cm cm cm cm cm cm cm cm 3 Lesion site MTG IFG (oper) IFG (oper) IFG IFG Putamen Inferior temporal IFG STG MTG IFG (tri) Mid/superior STG Amygdala MTG STG SMG STG Mid/superior Frontal SMG Insula STG Insula Hippocampus Insula Frontal Rolandic oper Rolandic oper Thalamus SMG Rolandic Oper Caudate Rolandic oper Insula Precentral Caudate Insula Putamen Putamen Insula STG Insula Hippocampus Hippocampus Cingulate (mid Heschl s gyrus Putamen and anterior) SMG Caudate Caudate Putamen Thalamus Precentral Precentral SMA Postcentral MTG ¼ middle temporal gyrus; STG ¼ superior temporal gyrus; SMG ¼ supramarginal gyrus; IFG ¼ inferior frontal gyrus; SMA ¼ supplementary motor area. 108 VAN HEES, ANGWIN, McMAHON, AND COPLAND

10 NAMING TREATMENT IN APHASIA 109 demographic details and lesion site information. All participants had English as a first or primary language prior to stroke, were right handed, and had normal or corrected-to-normal vision and hearing. None of the participants had a history of any other neurological disease or disorder, mental illness, head trauma, alcoholism, cerebral tumour or abscess, or any significant cognitive deficits (e.g., memory, attention). None of the participants had a reported history of moderate to severe apraxia of speech or dysarthria. Further, initial observations of each participant at the commencement of the study indicated that language production was not significantly impacted by motor speech impairment for any participant. All subjects gave their informed consent prior to participation in the study and were assessed using the Mini Mental State Examination (Folstein, Folstein, & McHugh, 1975), the Glasgow Depression Scale (Feher, Larrabee, & Crook, 1992), the Edinburgh Handedness Inventory (Oldfield, 1971), and Pure Tone assessment of hearing. The Western Aphasia Battery (WAB-R) was conducted to determine overall severity of language impairment and aphasia classification (Kertesz, 2007). In order to categorise participants into those with predominantly semantic deficits and those with predominantly post-semantic deficits, the Pyramids and Palm Trees Test (Howard & Patterson, 1992), the Boston Naming Test (Kaplan, Goodglass, & Weintraub, 1983), as well as the Comprehensive Aphasia Test (Swinburn, Porter, & Howard, 2004) were conducted. A naming battery consisting of 476 items from the International Picture Naming Project Database (Szekely et al., 2004) was also administered twice within the same week, and analysed with respect to proportion of semantically and phonologically related errors. Participants were categorised as having predominantly semantic impairments if they displayed impaired performance on the Pyramids and Palm Trees Test, similar impairments in both spoken and written naming, and the presence of semantic paraphasias in naming, as well as preserved realword reading and repetition suggesting intact lexical representations despite impaired semantics. In contrast, participants were categorised as having predominantly phonological impairments if they displayed good performance on the Pyramids and Palm Trees Test, the presence of phonological paraphasias in naming with little or no benefit of phonemic cueing, as well as impaired real-word reading and repetition suggesting impaired lexical representations despite intact semantic processing. Finally, participants were categorised with primary impairments in accessing lexical representations from semantics if they displayed good performance on the Pyramids and Palm Trees Test, preserved real-word reading and repetition, and benefited from phonemic cueing during naming suggesting intact lexical representations and semantic processing, however impaired mapping from semantics to phonology. Using this criteria, two participants were classified with predominantly semantic

11 110 VAN HEES, ANGWIN, McMAHON, AND COPLAND impairments (TP and BA), two participants were classified with predominantly phonological impairments (PS and HJ), and four participants were classified with impairments accessing lexical representations from semantics (JV, LW, TW, and TK). See Table 2 for language assessments results. Additionally, connected speech was assessed using five different tasks: request for procedural information (Tell me how you would go about writing and sending a letter), request for personal information (Tell me what you usually do on Sundays), narrative sample using a sequence of six pictures that told a story, picture description using the man in a tree scene (see Nicholas & Brookshire, 1993), as well as a free speech sample (Can you tell me a story about something important that happened to you in your life?). Procedure Three initial assessment sessions were completed prior to therapy in which all assessments were administered. Based on error responses from the naming battery, treatment items were individualised for each participant by selecting 90 items that were not able to be named on at least one out of two naming attempts. The 90 items were then split into three sets of 30 items and each set was assigned to either a treatment type (SFA or PCA) or to the untreated control set. For each participant, the three sets were matched for number of phonemes, syllables, and characters (Szekely et al., 2004), age of acquisition (Morrison, Chappell, & Ellis, 1997), Centre for Lexical Information (CELEX) Frequency (Davis, 2005), imageability (Wilson, 1988), as well as mean response time and percent name agreement (Szekely et al., 2004) (p..05). Additionally, each set was matched for number of correctly named items at baseline for each individual. Three therapy sessions were provided per week for four weeks (12 sessions in total). Each session continued until the full set of 30 items was completed. Therefore, there was some variation in time spent in therapy depending on severity of aphasia. For the four participants with milder naming deficits (JV, LW, TW, and TK), therapy sessions typically ranged from 45 up to 60 minutes. However, for the four participants with more severe naming deficits (PS, HJ, TP, and BA), therapy sessions typically ranged from 60 minutes up to 90 minutes. Half the sessions involved SFA and the other half involved PCA, where the type of therapy task was alternated each session and the order of treatment delivery counterbalanced among participants. After every fourth session, all treatment items as well as the untreated control set were probed for naming performance. Additionally, in a follow up session two to three weeks after the final session, all items were re-assessed to examine maintenance of treatment effects. The BNT and the five tasks comprising the speech

12 TABLE 2 Language assessment results for each participant Language Assessment PS JV LW TW HJ TK TP BA BNT (/60) P&PT Version 1 (/52) P&PT Version 5 (/52) CAT: Raw T score Raw T score Raw. T score Raw T score Raw T score Raw T score Raw T score Raw T score Comp/Spoken (/66) Comp/Written (/62) Repetition (/74) Naming Reading (/70) Writing (/76) Picture Description: Spoken Written NA NA NA NA WAB-R: Spontaneous Speech (/20) Comprehension (/10) Repetition (/10) Naming(/10) AQ (/100) Classification Conduction Anomic Anomic Anomic Conduction Anomic Anomic Anomic Severity Mild- Moderate Mild Mild Mild Moderate Mild Moderate Mild (Continued) NAMING TREATMENT IN APHASIA 111

13 Table 2. Continued. Language Assessment PS JV LW TW HJ TK TP BA Naming Battery: % Correct % Incorrect % Semantic errors % Phonological errors % Unrelated/No response % Perceptual errors Locus of Breakdown Semantic Semantic Postsemantic/ Phonological Semantics to Phonology Semantics to Phonology Semantics to Phonology Postsemantic/ Phonological Semantics to Phonology BNT ¼ Boston Naming Test; P&PT ¼ Pyramids and Palm Trees; CAT ¼ Comprehensive Aphasia Test; WAB-R ¼ Western Aphasia Battery Revised. indicates impaired performance. 112 VAN HEES, ANGWIN, McMAHON, AND COPLAND

14 NAMING TREATMENT IN APHASIA 113 sample were also re-assessed at follow-up to examine generalisation of treatment to naming and connected speech. Treatment Each picture was presented as a black line drawing in the centre of a matrix displayed on a Dell Latitude E6500 Laptop computer screen using Microsoft Office PowerPoint (2007). The delivery of the treatment tasks followed the same procedure as previous studies employing SFA and PCA (e.g., Boyle & Coelho, 1995; Coelho et al., 2000; Leonard et al., 2008). Firstly, participants were asked to name the item. Regardless of participants ability to name the item, they were then asked to produce the features of the item according to each cue word in the matrix. For SFA the cues were: group, use, action, properties, location, and association (Boyle & Coelho, 1995). For PCA the cues were: first sound, syllables, last sound, association, and rhyme (Leonard et al., 2008). As responses were provided, they were typed into the relevant boxes by the clinician. If a participant was unable to produce a response, the clinician provided a response both orally and in written form. After all the features were produced, the participant was asked to name the item again. Regardless of correct/incorrect response, the clinician then reviewed all the features of the object and asked the participant to name the item once more. If the participant was still unable to name the item, the clinician provided a model that the participant then repeated. Each session continued until all items from the treatment set were completed. RESULTS A weighted Wilcoxon one-sample test was used to identify whether improvement in naming accuracy pre-treatment (baseline measures from the two attempts of the naming battery and naming probe prior to the first treatment session) differed significantly from improvement in naming accuracy immediately post-treatment, or at follow-up assessment. Each item was scored as either correct (1) or incorrect (0) in the first, second and third baseline assessments, as well as in the post-treatment assessment (immediately post-treatment or at follow-up), and was then multiplied by the weightings 2, 1, 4, and 3 for each time point, respectively. Thus, if the sum of weighted scores centred on zero, improvement due to the treatment did not differ to improvement during baselines. Once the sum of weighted scores was calculated for each item, these scores where then analysed using a Wilcoxon one-sample test for each condition (PCA, SFA, and Untreated items). Seven out of eight participants (PS, LW, TW, HJ, TK, TP, and BA) improved significantly in naming accuracy for items treated using PCA compared to baseline scores (p,.05, one-tailed). Furthermore, six of the seven

15 114 VAN HEES, ANGWIN, McMAHON, AND COPLAND participants who significantly improved following PCA maintained improvements at 2 3 week follow-up (PS, LW, TW, TK, TP, and BA) (p,.05, onetailed). Four out of eight participants (PS, LW, TW, and HJ) improved significantly in naming accuracy of items trained using SFA compared to baseline scores (p,.05, one-tailed). Furthermore, three of the four participants who Figure 1. Naming accuracy data for each participant: B1-3 ¼ Baseline 1-3 (pre-treatment), P1-P3 ¼ Probe 1-3 (every 4 th session during treatment), FU ¼ Follow-up, PCA ¼ items treated using Phonological Components Analysis, SFA ¼ items treated using Semantic Feature Analysis, UNT ¼ Untreated items. ( p,.05 p,.01 p,.001).

16 NAMING TREATMENT IN APHASIA 115 significantly improved following SFA maintained improvements at 2 3 week follow-up (PS, TW, and HJ) (p,.05, one-tailed). No significant differences in naming accuracy were found between baseline scores and post-treatment scores for untreated items for all participants (p..05, one-tailed). See Figure 1 for individual results. Effect sizes were also calculated for participants who demonstrated treatment effects, using the Busk and Serlin (1992) method. Thresholds of 2.6, 3.9, and 5.8 were used to determine whether effect sizes were small, medium, or large, respectively (Beeson & Robey, 2006). Effect sizes ranged from small to large, and complemented the results of the Wilcoxon Test (see Table 3). To further investigate generalisation of treatment to untreated items, a McNemar s Test was used to examine significant changes in naming accuracy scores on the BNT administered pre- and post-therapy. Stimulus items on the BNT that also appeared in a participant s list of treatment items were removed from the analysis. Seven of the eight participants showed no significant changes between pre- and post-treatment on BNT scores (p..05, onetailed). Only one participant, TK, showed a significant improvement on BNT scores (p ¼.03, one-tailed) indicating some generalisation to untreated items for this participant. In addition to naming accuracy, an analysis of the type of errors made was also conducted for each participant. Errors were coded as either semanticallyrelated paraphasias, phonologically-related paraphasias, or no-responses, using the classification system used in Chenery, Murdoch, and Ingram (1996). A McNemar s Test was used to examine significant differences in the number of each error type made in the final baseline compared to scores immediately post-treatment as well as at follow-up assessment for each treatment set. Two participants, JV and TP, showed no significant TABLE 3 Results from effect size calculations PCA SFA Post-Tx Follow-up Post-Tx Follow-up PS LW TW HJ TK TP BA Effect size thresholds:.2.6 (small),.3.9 (medium), and.5.8 (large).

17 116 VAN HEES, ANGWIN, McMAHON, AND COPLAND changes in any error type at either time point (p..05, two-tailed). Three participants (PS, LW, and TW), showed a significant decrease in no-response errors for both treatment sets at both time points (p,.05, two-tailed). TK also showed a significant decrease in no-response errors for items treated with PCA at both time points, as well as items treated with SFA at followup assessment only (p,.05, two-tailed). HJ showed a significant decrease in phonologically-related errors for items treated with PCA immediately post-treatment (p,.05, two-tailed), however this was not maintained at follow up. In contrast, items treated with SFA showed a significant decrease in phonologically-related errors at follow-up assessment only (p,.05, twotailed). Finally, BA showed a significant decrease in semantically-related errors only for items treated with PCA at both time points (p,.05, twotailed). However, significant changes may only have been possible with individuals who had more errors pre-treatment, or errors restricted to one type. Thus, the results of error analysis need to be interpreted with caution. Speech samples were also analysed pre- and post-therapy using Systematic Analysis of Language Transcripts software (Miller & Iglesias, 2010). Measures that were analysed included total number of utterances, mean length of utterance, words per minute, total number of words, number of different words, type token ratio, number of maze words, as well as number of abandoned utterances, omitted words, and word errors. Some changes were identified preversus post-treatment; four participants (PS, HJ, TP, and BA) showed either increased total number of utterances or mean length of utterances across the five tasks. However, the other four participants (JV, LW, TW, and TK) did not show any discernible change. See Appendix 1 for detailed results of the speech sample analyses for each participant. DISCUSSION This study compared a semantically-based and a phonologically-based treatment task for naming impairments in eight people with aphasia, using a within subject alternating treatment design, keeping differences between task structure and response demands minimal. It was hypothesised that if the semantic and phonological treatment tasks targeted semantic and phonological processing, respectively, that participants with primarily semantic impairments would show greater benefit from the semantically-based therapy, and, vice versa, participants with primarily phonological impairments would show greater benefit from the phonologically-based therapy. However, if the treatment tasks were not selectively targeting specific levels of processing, no difference was expected between participants with different loci of impairments.

18 NAMING TREATMENT IN APHASIA 117 Seven of the eight participants made significant improvements immediately post-treatment for items treated with PCA, despite differences in loci of impairments. Only four participants significantly improved in naming items treated with SFA. Both participants with primarily semantic impairments did not significantly improve on naming items treated with the semantic task. Changes in the frequency of different error types were also found for six of the eight participants. Although improvements in naming accuracy for the untreated set were evident for all eight participants, these did not reach significance either immediately post-treatment or at follow-up assessment. Only TK showed a significant difference on the Boston Naming Test posttreatment, suggesting some generalisation. Additionally, four of the eight participants showed improvements in connected speech post-treatment in terms of an increased number of utterances and/or mean length of utterances. However, these results were likely to be impacted by severity of aphasia, where participants with mild anomia may have been more prone to ceiling effects compared to participants with more severe anomia. The results of the study do not support the hypothesis that the phonologically and semantically-based tasks would benefit individuals with predominantly phonological or semantic impairments, respectively. However, some differences were found between participants with different loci of impairments, suggesting the two treatments may have been targeting different mechanisms of processing. The following discussion will examine the relationship between each participant s locus of breakdown in naming and response to both treatment tasks. Possible mechanisms of treatment effects in terms of theories of word production will be explored, as well as a discussion of possible generalisation to connected speech, and finally some limitations of the current study. Relationship between locus of breakdown and response to treatment One question under debate within the aphasia literature is whether treatment for language impairments should target the locus of breakdown or focus on a relatively spared process (e.g., Drew & Thompson, 1999; Howard et al., 1985; Nettleton & Lesser, 1991). Although this issue is undoubtedly complicated by other factors such as the type and severity of the impairment, the relationship between locus of breakdown in naming and response to a particular treatment task remains an important area of enquiry. Increased knowledge of this relationship has the potential to inform and optimise individualised targeted treatment. Two participants whose pre-treatment assessments indicated impairments primarily in semantic processing, TP and BA, displayed similar treatment effects. TP and BA both showed significant improvements in naming

19 118 VAN HEES, ANGWIN, McMAHON, AND COPLAND accuracy for items treated with PCA, and both participants maintained significant improvements at follow-up for these items. In contrast, improvements in naming items treated with SFA failed to reach significance. Such results are in contrast to the notion that treatment should directly target the locus of breakdown, and provides some evidence that targeting the relatively spared process may actually be more beneficial in the case of impaired semantic processing. These results are in line with previous studies that found phonological therapy to be beneficial for individuals with semantic impairments. For example, Raymer et al. (1993) reported improved naming for four participants with impairments in semantics and lexical access following therapy involving phonological cueing. Nickels and Best (1996) also reported a case study of a participant with both semantic and phoneme assembly impairments, where phonological therapy resulted in improved naming whereas semantic therapy did not. Additionally, Drew and Thompson (1999) found semantic therapy to be ineffective for a person with lexical semantic impairments, where improvements were only found once phonological tasks were added to the therapy. Thus, the results of TP and BA provide further evidence that phonological tasks can improve naming in individuals with semantic impairments. However, the PCA treatment may not have directly targeted phonological processing for these individuals. It is also possible that the task strengthened the mappings between semantics and phonology, particularly as the task involved picture stimuli, which should activate semantic processing. Two participants whose pre-treatment assessments indicated impairments primarily in post-semantic processing (PS and HJ) showed significant improvements for both treatment sets immediately post-treatment. Previous studies have found both phonological and semantically-based treatments to be beneficial for individuals with post-semantic impairments (e.g., Howard et al., 1985; Lorenz & Ziegler, 2009). However, differences were found in terms of maintenance of treatment. PS maintained significant improvements for both treatment sets at follow-up assessment, whereas only the SFA items remained significant for HJ. Interestingly, HJ was more accurate at naming SFA items at follow-up than immediately post-treatment. Such results suggest that although PCA and SFA treatments may both be beneficial for individuals with post-semantic impairments, SFA may be more beneficial in terms of maintenance of treatment effects in some individuals. The remaining four participants whose pre-treatment assessments indicated impairments primarily in the mapping between semantics and phonology (JV, TK, LW, and TW) showed variable results. JV did not show significant improvements for either treatment set; TK only showed significant improvements for items treated with PCA; LW showed significant improvements for both treatment sets, however only maintaining significant improvements for items treated with PCA; and finally TW

20 NAMING TREATMENT IN APHASIA 119 showed significant improvements for both treatment sets that were both maintained at follow-up. However, all four participants with primary impairments in accessing phonology from semantics also had only mild naming deficits. As such, naming accuracy at baseline testing was relatively high. Therefore, the absence of treatment effects may also reflect ceiling effects for these participants. For example, for TK the lack of a significant treatment effect for items treated with SFA may be due to higher accuracy at baseline for this set compared to the PCA treatment set. Similarly, JV had the highest accuracy scores pre-treatment and failed to show significant effects for either treatment. Overall, some differences in the results are evident in terms of locus of breakdown and treatment effects. Participants with primarily semantic impairments showed greater effects for items treated with PCA, whereas participants with primarily post-semantic impairments benefited from both treatments, with greater maintenance of items treated with SFA. Participants with difficulty mapping semantic information onto the word form showed variable results, although these results were likely to be affected by ceiling effects. In the following section, we address the possible mechanisms of these results with respect to theories of word production. Possible mechanisms of treatment effects SFA and PCA tasks were chosen to target primarily semantic and phonological processing, respectively. However, both tasks included attempted naming, which would be expected to involve both semantic and phonological processing (Dell et al., 1997; Levelt, 1999). Thus, although the focus of SFA was to strengthen semantic representations related to a target item, or increase the semantic specificity of the target, production of the word form during the task would also engage processing at the level of phonology. Similarly, although the PCA task involved phonological analysis of the target item in order to strengthen word form representations or access to the word form, the presentation of a picture and production of the target word is likely to engage semantic processing. Given the above considerations (presence of both semantics and phonology in both treatments), it is also possible that both treatments could strengthen the mapping between semantics and phonology. However, as treatment outcome differed across the two treatments for some participants, this suggests that the treatments may have targeted different mechanisms of processing. For example, TP and BA were both identified with predominantly semantic impairments as their locus of breakdown in naming. They both showed significant improvements in naming accuracy for items treated with PCA, whereas improvements in items treated with SFA did not reach significance. The absence of a significant effect for items treated with SFA for TP and BA