Radiographic abnormalities and their clinical significance in patients with Parkinson disease who receive deep brain stimulation implants.

OBJECTIVE: Preoperative MR images obtained in patients with Parkinson disease (PD) undergoing deep brain stimulation (DBS) often reveal incidental radiographic abnormalities (RAs). These findings range from small changes to gross pathologies. The effect of these findings on patients' clinical outcomes is unknown. The authors characterized RAs in patients with PD who underwent DBS and assessed clinical outcomes. METHODS: Records of patients at the authors' institution with PD who underwent MRI for DBS electrode implantation from 2010 through 2022 were reviewed. RAs were identified from the official preoperative MRI reports. RAs were grouped into four general categories (ischemic changes, atrophy or degenerative changes [ADCs], structural abnormalities, and tumors) and correlated with clinical outcomes (including subjective clinical response, levodopa equivalent dose [LED], and Unified Parkinson's Disease Rating Scale Part III [UPDRS] score) at the 1-year and last available follow-ups. RESULTS: In this review, 160 patients were identified for initial analysis, with 135 presenting with ≥ 1 RAs. Of these 135 patients, 69.4% (111/160) had ischemic vascular changes, 39.4% (63/160) had ADCs, 16.9% (27/160) had structural changes, and 1.9% (3/160) had tumors. No differences in preoperative LED or UPDRS score were observed between these groups. After DBS, no differences in outcomes were observed between patients with RAs and those without RAs for both the 1-year and last follow-up time points, including mortality rates and times. Structural lesions were associated with lower mortality rates (OR 0.1, p = 0.04). ADCs were associated with a worse subjective clinical response at the 1-year (OR 0.50, p = 0.04) and last (OR 0.49, p = 0.03) follow-ups, but subjectively worse responses were not correlated with worse objective outcome measures. CONCLUSIONS: Most RAs have no significant effect on clinical outcomes in PD patients undergoing DBS. Generalized ADCs may be associated with poorer subjective responses and may warrant further discussion with the patient if diagnosed on preoperative MRI.

A Closer Look at Practice Effects in Mild Cognitive Impairment and Alzheimer's Disease.

Practice effects have become a potentially important variable regarding the diagnosis, prognosis, and treatment recommendations in mild cognitive impairment (MCI) and Alzheimer's disease (AD). However, the understanding of these short-term changes in test scores remains unclear. The current observational study sought to examine variables that influence the magnitude of short-term practice effects in MCI and AD, including demographic information, cognitive performance, daily functioning, and medical comorbidities. One hundred sixty-six older adults classified as cognitively intact, amnestic MCI, or mild AD were tested twice across 1 week with a brief battery of neuropsychological tests. Correlational and regression analyses examined the relationship of practice effects with demographic and clinical variables. Results indicated that practice effects were minimally related to demographic variables and medical comorbidities, but they were significantly related to cognitive variables, depressive symptoms, and daily functioning. These findings expand our understanding of practice effects in MCI and AD, and they may allow a better appreciation of how they could affect clinical care and research.

Change on the Repeatable Battery for the Assessment of Neuropsychological Status and its relationship to brain amyloid.

BACKGROUND: The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) has been associated with commonly used biomarkers of Alzheimer's disease (AD), including brain amyloid plaque density. However, less is known about if changes in the RBANS across time are also related to brain amyloid deposition. The current study sought to expand on prior work by examining the relationship between changes over time on the RBANS and amyloid deposition via positron emission tomography (PET). METHOD: One-hundred twenty-six older adults with intact or impaired cognition and daily functioning underwent repeat assessment with the RBANS across nearly 16 months, as well as had a baseline amyloid PET scan. RESULTS: In the entire sample, amyloid deposition was significantly related to change on all five Indexes and the Total Scale score of the RBANS, with greater amyloid being associated with worsening cognition. This pattern was also observed in 11 of 12 subtests. CONCLUSIONS: Whereas prior studies have identified a relationship between baseline RBANS and amyloid status, the current findings support that changes in the RBANS are also indicative of AD brain pathology, even if these findings are mediated by cognitive status. Although replication in a more diverse sample is needed, these results continue to support the use of the RBANS in AD clinical trials.

Change in the Quick Dementia Rating System Across Time in Older Adults with and without Cognitive Impairment.

BACKGROUND: The Quick Dementia Rating System (QDRS) is a brief, informant-reported dementia staging tool that approximates scores on the Clinical Dementia Rating Scale in patients with Alzheimer's disease (AD). OBJECTIVE: The current study sought to examine change in the QDRS across time, which is necessary for clinical and research efforts. METHODS: One-hundred ten older adults (intact, mild cognitive impairment [MCI], mild AD, classified with Alzheimer's Disease Neuroimaging Initiative criteria) were rated on the QDRS by an informant and had an amyloid positron emission tomography scan at baseline. The informant re-rated each participant on the QDRS after one year. Dependent t-tests compared the entire sample and various subgroups (e.g., cognitive status, amyloid status) on baseline and follow-up QDRS scores. RESULTS: In the entire sample, the Total score on the QDRS significantly increased (i.e., worsened) on follow-up (p < 0.001). When subgroups were analyzed, the MCI and mild AD subjects showed increasing (i.e., worsening) QDRS Total scores (both p < 0.001), but the intact subjects remained stable over time (p = 0.28). Additionally, those classified as being amyloid positive at baseline showed significantly increased QDRS Total scores at follow-up (p < 0.001) compared to those who were amyloid negative at baseline, whose QDRS Total scores remained stable over time (p = 0.63). CONCLUSION: The QDRS can potentially demonstrate worsening functioning status across one year, especially in those who have MCI or mild AD and those who are amyloid positive. Therefore, the current results preliminarily suggest that the QDRS may provide an efficient tool for tracking progression in clinical trials in AD.

Memorial familiarity remains intact for pictures but not for words in patients with amnestic mild cognitive impairment.

Understanding how memory breaks down in the earliest stages of Alzheimer's disease (AD) process has significant implications, both clinically and with respect to intervention development. Previous work has highlighted a robust picture superiority effect in patients with amnestic mild cognitive impairment (aMCI). However, it remains unclear as to how pictures improve memory compared to words in this patient population. In the current study, we utilized receiver operating characteristic (ROC) curves to obtain estimates of familiarity and recollection for pictures and words in patients with aMCI and healthy older controls. Analysis of accuracy shows that even when performance is matched between pictures and words in the healthy control group, patients with aMCI continue to show a significant picture superiority effect. The results of the ROC analysis showed that patients demonstrated significantly impaired recollection and familiarity for words compared controls. In contrast, patients with aMCI demonstrated impaired recollection, but intact familiarity for pictures, compared to controls. Based on previous work from our lab, we speculate that patients can utilize the rich conceptual information provided by pictures to enhance familiarity, and perceptual information may allow for post-retrieval monitoring or verification of the enhanced sense of familiarity. Alternatively, the combination of enhanced conceptual and perceptual fluency of the test item might drive a stronger or more robust sense of familiarity that can be accurately attributed to a studied item.