Sara Cavaco

Amnesia and Driving

Two experienced drivers who developed severe amnesia due to bilateral hippocampal lesions participated in a series of standardized challenges of driving performance and knowledge of driving rules. During drives in a high fidelity simulator and on the road in an instrumented vehicle, they demonstrated vehicle control similar to that of normal drivers on measures of steering, speed control, safety errors, and driving with distraction. Their knowledge of driving rules, safety procedures, and road sign meaning also was normal. However, both participants were impaired at following route directions, and both had unsafe responses in a difficult crash avoidance scenario on the simulator. These findings suggest that memory impairment acquired by experienced drivers does not impair most aspects of driving performance, but may increase safety risk under some challenging circumstances.

Cognitive reserve in multiple sclerosis: Protective effects of education.

Background: Recent data suggest that cognitive reserve modulates the adverse effects of multiple sclerosis (MS) pathology on cognitive functioning; however, the protective effects of education in MS are still unclear. Objective: To explore education as an indicator of cognitive reserve, while controlling for demographic, clinical and genetic features. Methods: A total of 419 MS patients and 159 healthy comparison (HC) subjects underwent a comprehensive neuropsychological (NP) assessment, and answered the Hospital Anxiety and Depression Scale. Based on the HC data, MS patients’ NP scores were adjusted for sex, age and education; and the estimated 5th percentile (or 95th percentile, when appropriate) was used to identify any deficits. Patients also performed the Mini-Mental State Examination (MMSE); and their human leucocyte antigen HLA-DRB1 and apolipoprotein E (ApoE) genotypes were investigated. Results: Patients with higher education were less likely (p < 0.05) to have cognitive deficits than those with lower education, even when controlling for other covariates. Other significant predictors of cognitive deficit were: age, Expanded Disability Status Scale (EDSS), Multiple Sclerosis Severity Scale (MSSS), and a progressive course. No significant association was found with the HLA-DRB1*15:01 or ApoE ε4 alleles. Conclusions: These results provide support to the use of education as a proxy of cognitive reserve in MS and stress the need to take into account education when approaching cognition in MS.

Olfactory dysfunction in multiple sclerosis: association with secondary progression

Objective: The Brief Smell Identification Test (B-SIT) was used to explore odour identification capacities in multiple sclerosis (MS). Methods: In total, 153 consecutive patients with MS and 165 healthy controls (HC) participated in the study. All participants were asked to answer the B-SIT and the Hospital Anxiety and Depression Scale (HADS). The Expanded Disability Status Scale (EDSS), the Multiple Sclerosis Severity Scale (MSSS), and the Mini-Mental State Examination (MMSE) were used for patients’ clinical and cognitive characterization. Results: Patients with MS (11.1%) were more impaired on the B-SIT than HC participants (3%). The frequency of impairment was higher for patients with secondary progressive (SPMS; 11/16, 68.8%) than relapsing–remitting (RRMS; 4/121, 3.3%) or primary progressive (2/16, 12.5%) courses. A threshold score of ≤ 8 on the B-SIT provided a sensitivity of 69% and a specificity of 97% in the identification of SPMS among patients with relapsing onset. The association between SPMS and impaired B-SIT remained statistically significant after adjusting for demographic (i.e. age and education), clinical (i.e. disease duration, EDSS, and MSSS), psychopathological (i.e. HADS anxiety and depression scores), and cognitive (i.e. MMSE) variables. Conclusions: A brief odour identification measure provided a good discrimination between SPMS and RRMS courses. A systematic assessment of olfactory functions may contribute to the development of clinical markers of SPMS.

Cognitive Functioning in Behcet's Disease

The impact of Behçets disease on higher cognitive functions is still poorly understood. We proposed (1) to characterize the neuropsychological profile of Behçets disease patients with (Neuro‐BD) and without (BD) neurological manifestations; (2) to identify which clinical, psychopathological, and genetic variables are related to neuropsychological performance; and (3) to explore the association between cognitive functioning and neuroimaging findings in BD patients. Fifteen Neuro‐BD and 35 BD patients in the nonactive phase of their illness underwent a neurological examination, performed a comprehensive battery of neuropsychological tests, and answered the hospital anxiety and depression scale. Human leukocyte antigen (HLA)‐B*51 genotyping was also performed. Patients’ neuropsychological performances were compared to those of healthy demographically matched subjects. Within one month from the testing date, a subset of 20‐BD patients underwent a magnetic resonance imaging (MRI) scan. Fifty‐three percent of Neuro‐BD and 40% of BD patients were impaired at least on one neuropsychological measure (i.e., digit span–forward). Poorer cognitive functioning in Neuro‐BD was associated with parenchymal involvement, whereas in BD it was related to presence of white matter changes in the frontal lobes, history of headache complaints, or higher levels of anxiety and depression. Current prednisone intake had a positive impact on neuropsychological performance. Disease duration, time since onset of neurological manifestations, or presence of HLA‐B*51 allele had no significant influence. Our results indicate that Behçets disease may affect cognitive abilities in the absence of overt neurological symptoms. These findings point to an insidious course of neurological involvement.

Task-specific contribution of the human striatum to perceptual–motor skill learning

Acquisition of new perceptual–motor skills depends on multiple brain areas, including the striatum. However, the specific contribution of each structure to this type of learning is still poorly understood. Focusing on the striatum, we proposed (a) to replicate the finding of impaired rotary pursuit (RP) and preserved mirror tracing (MT) in Huntingtons disease (HD); and (b) to further explore this putative learning dissociation with other human models of striatal dysfunction (i.e., Parkinsons disease and focal vascular damage) and two new paradigms (i.e., Geometric Figures, GF, and Control Stick, CS) of skill learning. Regardless of the etiology, participants with damage to the striatum showed impaired learning of visuomotor tracking skills (i.e., RP and GF), whereas the ability to learn skills that require motor adaptation (i.e., MT and CS) was not affected. These results suggest a task-specific involvement of the striatum in the early stages of skill learning.

Are Cognitive and Olfactory Dysfunctions in Neuropsychiatric Lupus Erythematosus Dependent on Anxiety or Depression

Objective. Depressed mood and cognitive impairments are common findings in systemic lupus erythematosus (SLE) and frequently coexist. We assessed the neuropsychological functioning of patients with SLE and investigated its association with psychopathological symptoms. Methods. A total of 85 patients with SLE (28 with neuropsychiatric syndromes: NPSLE) and 85 healthy control subjects with similar demographic characteristics were asked to perform a series of neuropsychological tests. A self-report questionnaire (the Hospital Anxiety and Depression Scale) was used to screen for psychopathology symptoms. Patients with SLE underwent a neurological examination. Results. Patients with NPSLE were more depressed and were more frequently impaired in cognitive and olfactory functions than controls or non-NPSLE patients. The NPSLE group remained statistically different from the other 2 groups on a series of neuropsychological measures (the Auditory Verbal Learning Test, Trail Making Test – Part A, Nine-Hole Peg Test, and Brief Smell Identification Test) even after control for elevated anxiety and depressed mood. Non-NPSLE and control groups were not significantly different regarding either psychopathological symptoms or neuropsychological functioning. Conclusion. Verbal memory, psychomotor speed, and olfaction are particularly vulnerable to dysfunction in NPSLE; impairment in these neuropsychological domains is not completely explained by psychopathology symptoms.

Abnormal Olfaction in Parkinson’s Disease Is Related to Faster Disease Progression

Introduction. A possible association between olfactory dysfunction and Parkinsons disease (PD) severity has been a topic of contention for the past 40 years. Conflicting reports may be partially explained by procedural differences in olfactory assessment and motor symptom evaluation. Methods. One hundred and sixty-six nondemented PD patients performed the Brief-Smell Identification Test and test scores below the estimated 20th percentile as a function of sex, age, and education (i.e., 80% specificity) were considered demographically abnormal. Patients underwent motor examination after 12 h without antiparkinsonian medication. Results. Eighty-two percent of PD patients had abnormal olfaction. Abnormal performance on the Brief-Smell Identification Test was associated with higher disease severity (i.e., Hoehn and Yahr, Unified Parkinsons Disease Rating Scale-III, Freezing of Gait questionnaire, and levodopa equivalent dose), even when disease duration was taken into account. Conclusions. Abnormal olfaction in PD is associated with increased severity and faster disease progression.

Musical memory in a patient with severe anterograde amnesia.

The ability to play a musical instrument represents a unique procedural skill that can be remarkably resilient to disruptions in declarative memory. For example, musicians with severe anterograde amnesia have demonstrated preserved ability to play musical instruments. However, the question of whether amnesic musicians can learn how to play new musical material despite severe memory impairment has not been thoroughly investigated. We capitalized on a rare opportunity to address this question. Patient S.Z., an amateur musician (tenor saxophone), has extensive bilateral damage to his medial temporal lobes following herpes simplex encephalitis, resulting in a severe anterograde amnesia. We tested S.Z.s capacity to learn new unfamiliar songs by sight-reading following three months of biweekly practices. Performances were recorded and were then evaluated by a professional saxophonist. S.Z. demonstrated significant improvement in his ability to read and play new music, despite his inability to recognize any of the songs at a declarative level. The results suggest that it is possible to learn certain aspects of new music without the assistance of declarative memory.

Appendectomy may delay Parkinson's disease Onset

Alpha‐synuclein (α‐Syn) is particularly abundant in the vermiform appendix, which makes this structure an anatomical candidate for the initiation of Parkinsons disease (PD) pathology. We hypothesized that history of appendectomy might affect PD clinical onset.

Auditory Verbal Learning Test in a Large Nonclinical Portuguese Population

This study aimed to produce adjusted normative data for the Portuguese version of the Auditory Verbal Learning Test (AVLT). The study included 1,068 community-dwelling individuals (736 women, 332 men) aged 18 to 93 years old (Mage = 56 years, SD = 18) who had educational backgrounds ranging from 0 to 24 years (M = 9.8 years, SD = 5.3). The results showed that sex, age, and education were significantly associated with AVLT performance. These demographic characteristics accounted for 24% to 35% of the variance of direct recall trials and for 8% to 39% of the variance of derived recall scores. The normative data for direct and derived recall scores are presented as regression-based algorithms to adjust for sex, age, and education with subsequent correspondence between adjusted scores and percentile distribution. The norms for the recognition correct score are presented as algorithms to estimate the recognition scores for 5th, 10th, and 18th percentiles for each combination of the variables sex, age, and education.