Verbal learning and memory in patients with dementia with Lewy bodies or Parkinson's disease with dementia.

This study compared verbal learning and memory in patients with autopsy-confirmed dementia with Lewy bodies (DLB) and patients with Parkinson's disease with dementia (PDD). A total of 24 DLB patients, 24 PDD patients, and 24 normal comparison participants were administered the California Verbal Learning Test. The three groups were matched on demographic variables, and the two patient groups were matched on the Mattis Dementia Rating Scale. The results indicated that DLB patients recalled less information than PDD patients on all but one recall measure and displayed a more rapid rate of forgetting. In contrast, the PDD patients committed a greater percentage of perseveration errors than the DLB patients. The two groups did not differ in the percentage of recall intrusion errors or any measures of recognition. A discriminant function analysis (DFA) using short-delay cued recall, percentage of perseveration errors, and List B recall differentiated the DLB and PDD groups with 81.3% accuracy. The application of the DFA algorithm to another sample of 42 PDD patients resulted in a 78.6% correct classification rate. The results suggest that, despite equivalent levels of general cognitive impairment, patients with DLB or PDD exhibit a different pattern of verbal learning and memory deficits.

Flanker compatibility effects in patients with Parkinson's disease: impact of target onset delay and trial-by-trial stimulus variation.

Parkinson's disease (PD) patients and healthy controls were administered a flanker task that consisted of the presentation of colored targets and distractors. Participants were required to attend to the center target and identify its color. The stimulus displays were either congruent (i.e., the target and flankers were the same color) or incongruent. The time between the onset of the flanker and the target color (the target onset delay) was either short or long. Results indicated that PD patients and controls did not differ in the magnitude of the flanker effect within individual trials in that both groups demonstrated a typical flanker effect at the short target onset delay and neither group demonstrated a flanker effect at the longer delay. However, when performance was examined on a trial-by-trial basis, PD patients demonstrated a slowing of reaction time relative to controls when having to make the same response across consecutive trials at longer inter-trial intervals when the flankers were incongruent across consecutive trials and the display on the second of two trials was incongruent. These results indicate that PD patients are impaired in inhibiting the distractors over an extended delay and that this deficit may impact motor responding in these patients, suggesting that the basal ganglia contribute to the interface of attention and action.

Impulsivity, neural deficits, and the addictions: the "oops" factor in relapse.

Impulsive behaviors are observed in a wide range of psychiatric disorders, including substance use, bipolar, attention-deficit hyperactivity, antisocial and borderline personality, gambling, and eating disorders. The shared phenotype of impulsivity is thought to significantly contribute to both the etiology and perpetuation of these disorders. In this review, we focus upon the relevance of impulsivity to the addictive disorders, particularly substance use disorders. First, the literature supporting the presence of impulsive behaviors prior to the onset of drug use and addiction is discussed. The relevance of impulsivity to relapse is then presented, with a focus on three distinct neurocognitive constructs: automaticity, response inhibition, and decision making. Automaticity is a quickly occurring relapse process resulting from the learned habits induced by persistent drug use. Addicted persons with response inhibition deficits are unable to suppress these previously reinforced behaviors. Decision-making deficits contribute to relapse through a poorly considered assessment of the consequences of drug use. The brain regions associated with each model of impulsive behavior are described, and relevant neurobiologic disruptions in addicted subjects are discussed in the context of their specific neurocognitive deficit(s). Descriptive confusions in the terminology and confounds inherent in the study of impulsivity are described. Empirical investigations documenting the hypothesized relationship between specific deficits in impulsive behaviors, coupled with their neurobiological correlates, and relapse should be the focus of future studies.

The ubiquity of memory retrieval deficits in patients with frontal-striatal dysfunction.

OBJECTIVE AND BACKGROUND: Previous studies have shown that patients with frontal-striatal dysfunction demonstrate improved performance on tests of recognition memory relative to free recall memory, suggesting deficits in retrieval processes. Not all studies, however, have indicated that all patients with frontal-striatal dysfunction display this profile. In this study, we examined the ubiquity of this "retrieval deficit" profile in a relatively large sample of patients with Parkinson disease (PD) or Huntington disease (HD). METHODS: Participants included 150 patients with PD and 65 patients with HD. Patients were classified as demonstrating a retrieval deficit or not based on a comparison of their standardized performances on the Recognition Discriminability and Long-Delay Free Recall indices from the California Verbal Learning Test. RESULTS: Results indicated that 1) a retrieval deficit was more prevalent in patients with HD than PD, 2) this group difference emerged only in patients with at least a mild level of global cognitive impairment, and 3) even when the profile did emerge more frequently in patients with HD, it was present in only 44% of the patients. CONCLUSIONS: These findings suggest that not all patient groups with frontal-striatal dysfunction display a retrieval deficit profile, but in groups that do (ie, patients with HD), it is more likely to appear in individuals with greater cognitive impairment.

Is a perseveration a perseveration? An evaluation of cognitive error types in patients with subcortical pathology.

This study investigated several constructs of executive functioning in a group of 77 patients with subcortical pathology. Specifically, we examined the validity of categorizing perseverative errors as "recurrent," "stuck-in-set," or "continuous," as proposed by Sandson and Albert (1984). A principal components analysis of 2 measures of recurrent perseveration, 2 measures of stuck-in-set perseveration, and 2 measures of intrusive errors yielded a 2 component solution with stuck-in-set perseverations and intrusive errors loading on Component 1, and recurrent perseverations loading on Component 2. Presence of a continuous perseveration on a graphomotor test was significantly associated with higher factor scores on Component 1, but not Component 2. The stuck-in-set perseveration and intrusion component was associated with the majority of the other neuropsychological tests administered, including tests of executive function and memory. The recurrent perseveration component was not associated with the other measures of cognitive functioning. Presence of a continuous perseveration was associated with executive function but not memory measures. This study provides evidence that recurrent perseverations are distinct from the other types of perseverative and intrusive errors, and that stuck-in-set and intrusive errors are good indicators of general cognitive functioning in patients with subcortical pathology.

Mayo's Older African American Normative Studies: norms for the Mattis Dementia Rating Scale.

Normative data are presented for older African Americans on the Mattis Dementia Rating Scale (DRS). These data were collected as part of Mayo's Older African Americans Normative Studies (MOAANS) in an effort to develop age-appropriate norms for African Americans elders on commonly used measures in neuropsychological assessment. In this study, the DRS was administered to 307 MOAANS participants ranging in age from 56 to 94 years. Age-corrected subtest and total scores were derived based on percentile ranks from actual frequency distributions across seven age ranges. Also presented is a regression-based computational formula that may be applied to the age-corrected DRS total score to further correct for years of education. These norms should help improve interpretation of DRS performance in African Americans and allow for greater diagnostic accuracy in patients with early cognitive decline.

Semantic and cross-case identity priming in patients with Parkinson's disease.

Semantic and cross-case identity priming were investigated in nondemented patients with Parkinson's disease (PD) and controls using the Lexical Decision Task. Three conditions were administered that consisted of the presentation of prime and target word pairs. In the semantic priming condition the word pairs were semantically related (e.g., table-CHAIR), in the cross-case identity priming condition the word pairs consisted of the same word (e.g., noise-NOISE), and in the unrelated condition the word pairs were not related semantically (e.g., guns-DEEP). A fourth condition was also administered that consisted of the presentation of a prime word and a pronounceable nonword target (e.g., starved-FORVE). Participants were asked to indicate whether the target was a real word or a nonword. The prime and target were separated by either a short or long (250 ms or 1000 ms) stimulus onset asynchrony (SOA). Results indicated that PD patients displayed normal semantic priming (i.e., faster responding to the target in the semantic condition as compared to the unrelated condition) at both the short and long SOA. Similarly, PD patients displayed normal cross-case identity priming (i.e., faster responding to the target in the identity condition relative to the unrelated condition) at the long SOA. At the short SOA, however, PD patients displayed hyper identity priming relative to controls (134 ms vs. 50 ms). These results suggest that semantic processes are normal in nondemented PD patients but that the processes involved in accessing lexical information may be overly activated in these patients.

Negative priming in patients with Parkinson's disease: evidence for a role of the striatum in inhibitory attentional processes.

Patients with Parkinson's disease (PD) and normal controls (NCs) performed a negative priming task. NCs displayed the normal pattern of negative priming in that relative to a control condition they were slower to identify a target within a stimulus array when it had been a distractor in the previous array. PD patients did not display any evidence of negative priming. In contrast, both PD patients and NCs displayed statistically the same level of spatial priming and response repetition cost. Regression analyses indicated that although symptom severity, symptom characteristics, and global cognitive functioning were not reliable predictors of negative priming or spatial priming in PD patients, greater symptom severity and poorer global cognitive functioning were associated with less response repetition cost. The possible role of the striatum in negative priming, spatial priming, and response repetition cost is discussed.