Association of Motor and Cognitive Symptoms with Health-Related Quality of Life and Caregiver Burden in a German Cohort of Advanced Parkinson's Disease Patients.

Parkinson's disease (PD) is a chronic progressive movement disorder with severe reduction in patients' health-related quality of life (HR-QoL). Motor and cognitive symptoms are especially linked with decreased PD patients' HR-QoL. However, the relationship of these symptoms to caregiver burden is relatively unclear. Influence of the Montreal Cognitive Assessment scale (MoCA) as a cognitive screening tool and Movement Disorders Society Unified Parkinson's disease Rating Scale MDS-UPDRS symptoms in relation to patients' HR-QoL and caregivers` burden was analyzed. PD patients (n = 124) completed MDS-UPDRS, MoCA, and the PD questionnaire 8 (PDQ-8) as a measure of quality of life. Caregivers (n = 78) were assessed by the PD caregiver burden inventory (PDCB). PDQ-8 and PDCB scores were regressed on MDS-UPDRS subscales and MoCA subscores. PDQ-8 correlated with attention (R 2 0.1282; p < 0.001) and executive (R 2 0.0882; p 0.001) MoCA subscores and all parts of the MDS-UPDRS. PDCB correlated most strongly with MDS-UPDRS part III motor symptoms (R 2 0.2070; p < 0.001) and the MoCA attention subscore (R 2 0.1815; p < 0.001). While all facets of PD symptoms assessed by the MDS-UPDRS relate to PD patients' quality of life, motor symptoms are the most relevant factor for the prediction of caregiver burden. In addition, patients' attentional symptoms seem to affect not only them, but also their caregivers. These findings show the potential of a detailed analysis of MDS-UPDRS and MoCA performance in PD patients.

The neural correlates of verb and noun processing. A PET study.

The hypothesis that categorical information, distinguishing among word classes, such as nouns, verbs, etc., is an organizational principle of lexical knowledge in the brain, is supported by the observation of aphasic subjects who are selectively impaired in the processing of nouns and verbs. The study of lesion location in these patients has suggested that the left temporal lobe plays a crucial role in processing nouns, while the left frontal lobe is necessary for verbs. To delineate the brain areas involved in the processing of different word classes, we used PET to measure regional cerebral activity during tasks requiring reading of concrete and abstract nouns and verbs for lexical decision. These tasks activated an extensive network of brain areas, mostly in the left frontal and temporal cortex, which represents the neural correlate of single word processing. Some left hemispheric areas, including the dorsolateral frontal and lateral temporal cortex, were activated only by verbs, while there were no brain areas more active in response to nouns. Furthermore, the comparison of abstract and concrete words indicated that abstract word processing was associated with selective activations (right temporal pole and amygdala, bilateral inferior frontal cortex), while no brain areas were more active in response to concrete words. There were no significant interaction effects between word class and concreteness. Taken together, these findings are compatible with the view that lexical-semantic processing of words is mediated by an extensive, predominantly left hemispheric network of brain structures. Additional brain activations appear to be related to specific semantic content, or, in the case of verbs, may be associated with the automatic access of syntactic information.

Word and picture matching: a PET study of semantic category effects.

We report two positron emission tomography (PET) studies of cerebral activation during picture and word matching tasks, in which we compared directly the processing of stimuli belonging to different semantic categories (animate and inanimate) in the visual (pictures) and verbal (words) modality. In the first experiment, brain activation was measured in eleven healthy adults during a same/different matching task for textures, meaningless shapes and pictures of animals and artefacts (tools). Activations for meaningless shapes when compared to visual texture discrimination were localized in the left occipital and inferior temporal cortex. Animal picture identification, either in the comparison with meaningless shapes and in the direct comparison with non-living pictures, involved primarily activation of occipital regions, namely the lingual gyrus bilaterally and the left fusiform gyrus. For artefact picture identification, in the same comparison with meaningless shape-baseline and in the direct comparison with living pictures, all activations were left hemispheric, through the dorsolateral frontal (Ba 44/6 and 45) and temporal (Ba 21, 20) cortex. In the second experiment, brain activation was measured in eight healthy adults during a same/different matching task for visually presented words referring to animals and manipulable objects (tools); the baseline was a pseudoword discrimination task. When compared with the tool condition, the animal condition activated posterior left hemispheric areas, namely the fusiform (Ba 37) and the inferior occipital gyrus (Ba 18). The right superior parietal lobule (Ba 7) and the left thalamus were also activated. The reverse comparison (tools vs animals) showed left hemispheric activations in the middle temporal gyrus (Ba 21) and precuneus (Ba 7), as well as bilateral activation in the occipital regions. These results are compatible with different brain networks subserving the identification of living and non-living entities; in particular, they indicate a crucial role of the left fusiform gyrus in the processing of animate entities and of the left middle temporal gyrus for tools, both from words and pictures. The activation of other areas, such as the dorsolateral frontal cortex, appears to be specific for the semantic access of tools only from pictures.

The effects of semantic category and knowledge type on lexical-semantic access: a PET study.

Neuropsychological studies of patients with category-specific recognition disorders, as well as PET investigations of semantic category effects in visual recognition tasks, have led some authors to the hypothesis that visual-perceptual knowledge plays a crucial role in the recognition of natural items, such as animals, while functional-associative information is more important for the recognition of man-made tools. To study the cerebral correlates of the retrieval of different types of semantic knowledge about living and nonliving entities, we performed a PET experiment in which normal subjects were required to access visual- and functional-associative information related to visually presented words corresponding to animals and tools. The experimental conditions were the following: (1) Rest. (2) Baseline: letter detection in pseudo-words. (3) Animal, visual knowledge: decide whether the animal has a long or short tail with respect to the body. (4) Animal, associative knowledge: decide whether the animal is typically found in Italy. (5) Tool, visual knowledge: decide whether the object is longer than wider or vice versa. (6) Tool, functional knowledge: decide whether the object is typically used as a kitchen tool. Lexical-semantic access (all lexical conditions pooled) activated the prefrontal cortex on the left and the parietal-occipital junction and posterior cingulate cortex bilaterally. An analysis of the individual experimental conditions in comparison with the nonword baseline showed that accessing visual versus associative knowledge was associated with different activation patterns: predominantly frontal in the case of visual features, temporoparietal for associative knowledge. While the activation patterns involved similar areas for living and nonliving entities, in the case of the latter they were restricted to the left hemisphere. The analysis of main effects confirmed these findings: there were several significant differences in the visual-associative comparison, while category-related differences were less prominent. These findings indicate that the retrieval of different types of knowledge is associated with distinct patterns of brain activation; on the other hand, category-related differences were less evident than in picture matching and naming tasks.

Distinct brain loci in deductive versus probabilistic reasoning.

Deductive versus probabilistic inferences are distinguished by normative theories, but it is unknown whether these two forms of reasoning engage similar cerebral loci. To clarify the matter, positron emission tomography was applied during deductive versus probabilistic reasoning tasks, using identical stimuli. Compared to a language comprehension task involving the same stimuli, both probabilistic and deductive reasoning increased regional cerebral blood flow (rCBF) bilaterally in the mesial frontal region and in the cerebellum. In the direct comparison, probabilistic reasoning increased rCBF in left dorsolateral frontal regions, whereas deductive reasoning enhanced rCBF in associative occipital and parietal regions, with a right hemispheric prevalence. The results suggest that reasoning about syllogisms engages distinct brain mechanisms, depending on the intention to evaluate them deductively versus probabilistically.