Strategies in Comprehension of Relative Clauses by Parkinsonian Patients

Abstract

Twenty patients with Parkinson disease (PD) and twenty normal control subjects (NC) matched on age, sex, education and socio-economic status (SES) were tested for comprehension of four types of relative clauses with complex thematic roles (syntax) and no semantic and pragmatic constraints (reversible) in a sentence-picture matching task. The results show a clear language impairment for PD patients compared to NC. Additional evidence from testing school children in grade 1 (G1) and grade 6 (G6) indicates that G1 children perform similar to PD patients and G6 children perform as high as NC. The overall picture of the findings suggests: (1) PD patients process sentences with complex thematic roles and semantic reversibility on a heuristic and not on an algorithmic basis, a type of behavior assumed to be associated with frontal lobe dysfunction; (2) PD patients display some patterns of language behavior similar to those observed in aphasics. Similarities in language behavior between PD patients and G1 children are discussed with regard to the "regression hypothesis" (Jacobson, 1968).

Assessing Resource Demands during Sentence Processing in Parkinson's Disease

“…Paralleling previous work in our laboratory and elsewhere (Cohen et al, 1994;Geyer & Grossman, 1994;Grossman et al, 1991Grossman et al, , 1992Kemmerer, 1999;Lieberman et al, 1990Lieberman et al, , 1992Natsopoulos et al, 1991Natsopoulos et al, , 1993Ullman et al, 1997), we found that the sentence comprehension impairment in PD when measured with a traditional procedure is most evident for grammatically complex sentences. PD patients thus have relatively greater difficulty with sentences containing object-gap subordinate clauses than subject-gap subordinate clauses, particularly when it is the subordinate clause that is being probed.…”

“…Sentences with object-gap subordinate clauses have a noncanonical word order where comprehension appears to benefit from executive resources such as inhibition, working memory, information processing speed, and planning. Patients with PD have considerable difficulty understanding object-gap sentences (Grossman et al, 1991(Grossman et al, , 1992Lieberman et al, 1990Lieberman et al, , 1992Natsopoulos et al, 1991Natsopoulos et al, , 1993. We have also shown that PD patients are impaired in their comprehension of other, noncanonical sentence structures (Geyer & Grossman, 1994).…”

“…However, there has been considerable controversy concerning the basis for this impairment. On the one hand, several reports have emphasized the possibility that some aspect of grammatical processing is impaired in PD (Cohen et al, 1994;Lieberman et al, 1992;Natsopoulos et al, 1991Natsopoulos et al, , 1993Ullman et al, 1997). Others have related the sentence comprehension impairment in PD to a limitation in executive resources (Geyer & Grossman, 1994;Grossman et al, 1992;Kemmerer, 1999;Waters & Caplan, 1997).…”

“…Much evidence has accumulated to indicate that healthy subjects encounter greater difficulty and take longer to understand sentences with subordinate clauses containing object gaps (e.g., ''The boy that the girl followed is friendly'') compared to sentences with subordinate clauses containing subject gaps (e.g., ''The boy that followed the girl is friendly'') (Ferreira et al, 1996;Ford, 1983;Frazier & Rayner, 1982). This relative difficulty with object-gap clauses compared to subject-gap clauses is exaggerated in PD, and this has been attributed to the extra grammatical demands needed to understand the former type of sentence compared to the latter type of sentence (Natsopoulos et al, 1991(Natsopoulos et al, , 1993. PD patients were also found to be impaired in their performance on a sentence-picture matching task assessing a variety of grammatical forms (Lieberman et al, 1992).…”

Language Processing in Parkinson's Disease Patients Without Dementia

“…Lieberman et al (1990) attributed the sentence comprehension errors in PD to "some deterioration of the patient's ability to make use of the syntactic 'rules' involved in English" (1990, p. 364). Similarly, researchers have attributed the sentence comprehension deficit to an impairment of some aspects of grammatical processing as such (Cohen et al, 1994;Natsopoulos et al, 1991Natsopoulos et al, , 1993. However, according to Lieberman et al (1990), the cognitive impairments and syntactic comprehension deficits in PD have a common physiological basis; they are both caused by disruption of the cortico-striato-cortical circuits.…”