How are inflectional affixes organized in the mental lexicon?: evidence from the investigation of agreement errors in agrammatic aphasics.

Recent psycholinguistic studies have provided evidence that regularly inflected words are decomposed into stems and affixes, both of which have their own representations in the mental lexicon. Specific models of the lexical organization of inflectional affixes have, however, only rarely been investigated in psycho- or neurolinguistic work. We test two recently proposed theoretical models: a representation of affixes (i) in default inheritance trees (Corbett and Fraser, 1993) and (ii) in underspecified paradigms (Wunderlich, 1996). Based on an analysis of agreement errors in elicited speech-production data of German agrammatic aphasics, we argue that affixes are organized with respect to the morphosyntactic features they encode. Specifically, our data indicate that inflectional affixes are best captured within an underspecified paradigm.

Psycholinguistic evidence for the underspecification of morphosyntactic features.

This paper investigates the paradigmatic relations between inflected word forms (or their affixes) and the feature specifications of these elements. In two sentence-matching experiments German speakers had to decide whether sentence pairs involving inflected adjectives or determiners were identical or not. In both experiments, there was a delay when an inflected form contained positive feature specifications for grammatical features that did not match the feature specifications of the grammatical context in which it appeared. No delay, however, occurred when an incorrectly inflected form had mismatching negative specifications, whereas its positively specified features matched the respective positive features of the context. This result provides evidence for a different status of positively and negatively specified morphosyntactic features. It supports the idea of radical underspecification according to which only positive feature specifications are part of the representations of morphologically complex forms or affixes, whereas negative feature specifications are assigned on the basis of paradigmatic contrasts.

[Unusual cause of macrohematuria in a 29-year-old woman]. / Seltene Ursache einer Makrohämaturie bei einer 29-jährigen Patientin.

HISTORY AND ADMISSION FINDINGS: We report on the case of a young women presenting with macrohaematuria, petechiae and strong headaches. INVESTIGATIONS: Laboratory showed a thrombotic microangiopathy with helmet cells, increased LDH levels (>600 U/l), and thrombocytopenia (<40,000/µl). DIAGNOSIS, TREATMENT AND COURSE: Due to strong haemolytic activity and headache with blurred vision, immediate plasma separation with fresh frozen plasma was commenced. Markedly decreased ADAMTS13 activity and detection of anti-ADAMTS13 antibodies were consistent with the diagnosis of idiopathic thrombotic thrombocytopenic purpura. In total, 11 plasma separations were required to stop disease activity. In parallel, immunosuppressive therapy using glucocorticoids was initiated. The patient was discharged from the hospital in a good general condition and with normalized laboratory findings 26 days after hospitalization. CONCLUSIONS: All patients with anemia and thrombocytopenia should be tested for haemolysis and helmet cells. An early diagnosis and initiation of necessary therapy are determining for the clinical outcome.