A comparison with previous studies on aphasia and PADs

At this point in the discussion, it is interesting to draw a comparison between the collected data and those found in previous studies on aphasia and on PADs. As underlined in Chapter 3, a direct comparison across languages with respect to phenomena concerning GG is highly problematic because GG systems widely differ across languages. The comparison is therefore limited to studies that concern Italian-speaking participants.

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With respect to aphasia, the present data confirm the results of previous studies, but also offer the possibility to highlight at least one interesting difference. As in Badecker et al. (1995) and in Luzzatti and De Bleser (1996), I find an overall spared access to GG in regular nouns.

As expected, one further characteristic that PADs share with aphasics is an enhanced difficulty at retrieving the proper GG for opaque words. In both cases, speakers with impaired cognitive abilities struggle at dealing with words characterized by the final marker -e. However, an interesting observation emerges from the comparison between the present study and the one by Luzzatti & De Bleser (1996). The two aphasic speakers tested in the latter showed clear signs of performance improvement in the case of derived nouns, meaning that they could analyse words into their morphologic components and recognize derivational morphemes that are specified for gender although ending in -e. In contrast, the present study shows the reversed pattern: PADs do not benefit from the presence of derivational morphology marked for GG and even experience more difficulties in correspondence to derived nouns. This means that PADs are sensitive to the internal complexity of derived nouns, but they do not succeed in exploiting the information on GG.

With respect to previous studies on Italian-speaking PADs, the present results seem to contradict those presented by Paganelli et al. (2003) at first. In the cited study, authors do not find signs of gender activation when PADs experience TOT-states, while they found them in normal controls. This might be read as a sign of impaired activation of GG.

However, I agree with the author in claiming that the effect might derived from a more basic source, namely a failed activation of the correct conceptual and semantic information. The discrepancy between the results in the present and in the cited study should therefore be ascribed to the difference between the tasks in use. In Paganelli et al.

(2003), the performance required the complete retrieval of lexical items, starting from its conceptual components to the phonetic realization. In contrast, the task in use in the present study provided the lexical item through visual input, thus activating the process of lexical retrieval from the opposite direction, which results in a lower involvement of semantic activation for task completion.

Finally, the data can provide further support to the results discussed in Manenti et al. (2004), in which PADs show sensitivity to gender priming in lexical retrieval. The two

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studies taken together argue for a (rather) spared status of GG in the linguistic competence of patients with Alzheimer.

4.5 Conclusions

In the present chapter, I discussed data from a grammatical gender retrieval task performed by 38 PADs and 21 COs (healthy elderly speakers). Overall, the performance of PADs was not at ceiling as it was for COs, but still, levels of accuracy above 93%

confirmed that the process of GG retrieval is well mastered by PADs. Therefore, PADs are not impaired at retrieving syntactic information attached to lexical entries. Overall, mistakes were as low as 3.5% of the total amount of experimental trials. In particular, PADs were very accurate on regular nouns, which suggests that the form-based route to GG access is preferred over the direct access to the information. This claim is further supported by the fact that mistakes affecting irregular nouns were all of the over-regularization kind, with GG assigned in consideration of the final word-marker. The two observations taken together reveal that PADs crucially rely on the procedural mechanism, and they resort to this when they face difficulties with irregular nouns.

In contrast, despite the low number of registered mistakes on opaque nouns, these were informative about slight tendencies within patients’ performance. Indeed, in this category of nouns, mistakes prevailed on derived rather than on simple nouns, on nouns with no natural gender rather than on nouns with natural gender and on feminine rather than on masculine nouns.

The first effect is due to the fact that PADs might perceive the higher complexity of derived nouns and be incapable of retrieving the correct GG from the derivational suffix. Different frequency rates might have played a role in this, however the asymmetry opens to a comparison with the agrammatic speakers in Luzzatti and De Bleser (1996), who actually performed better on derived than on simple nouns (on a similar list of items).

Furthermore, PADs seem to tend to restore to other strategies when direct access to GG fails and final marker -e does not offer any cue for form-based retrieval. One of these strategies builds on natural gender as a spared semantic category in PADs, who therefore are more successful on nouns endowed with natural gender than on nouns depicting artefacts or abstract concepts.

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When natural gender is not at hand, PADs finally restore to masculine as a default gender, and assign it to opaque nouns, for which no other route to correct retrieval can be followed. For obvious reasons, this last strategy is successful with masculine nouns, but not with feminine ones, which are affected by a higher rate of mistakes.

In conclusion, I would like to underline once more that the described phenomena are minor tendencies, as GG retrieval is actually well preserved in PADs. The low number of mistakes does not allow for any sound claim with respect to the potential presence of forms of impairment. This further confirms that speakers store semantic and syntactic information at separate levels and can suffer from a dissociated impairment, as in the case of PADs, who are spared at the latter but not at the former.

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5 RELATIVE CLAUSES AND Wh-QUESTIONS:

AN OVERVIEW

5.0 Introduction

In the present chapter I will illustrate some relevant characteristics of Wh-questions and relative clauses, the two kinds of clauses that I will use in order to sample the capacity of PADs to process complex sentence structures. The main reason to include the two clause types in the study is that they both entail a phrasal movement to the higher functional field of the sentence. The movement takes place in order to satisfy requirements of the scope-discourse type, which are determined in turn by the specific semantic of the sentence to be realized, either a question or a modification of a nominal phrase (as in the case of restrictive relative clauses). Previous research on aphasia (Avrutin, 2000; Friedmann, 2002; Garraffa & Grillo, 2008; Grillo, 2008, a.m.o.) and on L1 acquisition (De Vincenzi et al., 1999; Friedmann et al., 2009; a.m.o.) pointed out that syntactic derivations are problematic when they imply A-bar movement to the CP-layer. Therefore, they turn into privileged points of observation for the evaluation of the grammar used by speakers.

Precisely, the two structures entail an instantiation of the so-called Wh-movement, which is responsible for the movement of a phrase to the CP-layer and for leaving a gap in the clause. However, the semantic function of the operators that allow the derivations are different. In the case of Wh-questions, the operator represents a variable in the sentence, which must receive a value. In the case of Relative Clauses, the clause contributes to the restriction of a nominal element in the matrix clause. Besides, Wh-questions can be realized both in the form of root questions and in the form of embedded clauses, while relative clauses are subordinates, due to their nature of being attached to an argument in the matrix clause. Therefore, Wh-questions and Relative Clauses share some structural properties while differing on others, a combination which allows for different observations and comparisons.

The present Chapter is organized as follow. In section 5.1 I recall the basic mechanism allowing for the derivation of both Wh-questions and RCs. Sections 5.2 and

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5.3 deal with Wh-questions from a structural point of view and review relevant works in the syntax of Wh-questions. The same procedure is followed in section 5.4 for Relative Clauses. The second part of the Chapter is devoted to empirical studies on the processing of both structures and how these contribute to the linguistic debate. In section 5.5 I review relevant works on the processing of RCs both in adults, in children and in aphasic patients.

In 5.6 it will be the turn of experimental studies on Wh-questions. The reasons for this order of presentation is that the amount of experimental work run on the processing of RCs not only quantitatively exceeds the one on Wh-questions, but it is also the case that the former often influenced and guided the latter. Finally, section 5.7 will provide with a summary of the relevant information for the design of the experiments on the comprehension of Wh-questions (Chapter 6) and RCs (Chapter 7) in PADs.