Melissa M. Amick

Neuropsychological deficits associated with driving performance in Parkinson's and Alzheimer's disease

Neuropsychological and motor deficits in Parkinsons disease that may contribute to driving impairment were examined in a cohort study comparing patients with Parkinsons disease (PD) to patients with Alzheimers disease (AD) and to healthy elderly controls. Nondemented individuals with Parkinsons disease [Hoehn & Yahr (H&Y) stage I-III], patients with Alzheimers disease [Clinical Demetia Rating scale (CDR) range 0-1], and elderly controls, who were actively driving, completed a neuropsychological battery and a standardized road test administered by a professional driving instructor. On-road driving ability was rated on number of driving errors and a global rating of safe, marginal, or unsafe. Overall, Alzheimers patients were more impaired drivers than Parkinsons patients. Parkinsons patients distinguished themselves from other drivers by a head-turning deficiency. Drivers with neuropsychological impairment were more likely to be unsafe drivers in both disease groups compared to controls. Compared to controls, unsafe drivers with Alzheimers disease were impaired across all neuropsychological measures except finger tapping. Driving performance in Parkinsons patients was related to disease severity (H&Y), neuropsychological measures [Rey Osterreith Complex Figure (ROCF), Trails B, Hopkins Verbal List Learning Test (HVLT)-delay], and specific motor symptoms (axial rigidity, postural instability), but not to the Unified Parkinson Disease Rating Scale (UPDRS) motor score. Multifactorial measures (ROCF, Trails B) were useful in distinguishing safe from unsafe drivers in both patient groups.

Frontostriatal circuits are necessary for visuomotor transformation : Mental rotation in Parkinson's disease

The mental rotation of objects requires visuospatial functions mediated by the parietal lobes, whereas the mental rotation of hands also engages frontal motor-system processes. Nondemented patients with Parkinsons disease (PD), a frontostriatal disorder, were predicted to be impaired on mentally rotating hands. Side of PD motor symptom onset was investigated because the left motor cortices likely have a causal role in hand mental rotation. The prediction was that patients with right-side onset (RPD, greater left-hemisphere dysfunction) would commit more errors rotating hands than patients with left-side onset (LPD). Fifteen LPD, 12 RPD, and 13 normal control adults (NC) made same/different judgments about pairs of rotated objects or hands. There were no group differences with objects. When rotating hands, RPD, but not LPD, made more errors than the NC group. A control experiment evaluated whether visual field of presentation explained differences between PD subgroups. In the first experiment (1A), the hand to be mentally rotated was presented in the right visual field, but here (1B) it was presented in the left visual field. Only the LPD group made more errors than the NC group. The evidence suggests a double dissociation for the RPD and LPD groups between tasks differing in visual-field presentation. The findings indicate that hemifield location of a to-be-rotated hand stimulus can cause the hemispheric frontoparietal networks to be differentially engaged. Moreover, frontostriatal motor systems and the parietal lobes play a necessary role during the mental rotation of hands, which requires integrating visuospatial cognition with motor imagery.

A recommended scale for cognitive screening in clinical trials of Parkinson's disease

Cognitive impairment is common in Parkinsons disease (PD). There is a critical need for a brief, standard cognitive screening measure for use in PD trials whose primary focus is not on cognition. The Parkinson Study Group (PSG) Cognitive/Psychiatric Working Group formed a Task Force to make recommendations for a cognitive scale that could screen for dementia and mild cognitive impairment in clinical trials of PD where cognition is not the primary outcome. This Task Force conducted a systematic literature search for cognitive assessments previously used in a PD population. Scales were then evaluated for their appropriateness to screen for cognitive deficits in clinical trials, including brief administration time (<15 minutes), assessment of the major cognitive domains, and potential to detect subtle cognitive impairment in PD. Five scales of global cognition met the predetermined screening criteria and were considered for review. Based on the Task Forces evaluation criteria the Montreal Cognitive Assessment (MoCA), appeared to be the most suitable measure. This Task Force recommends consideration of the MoCA as a minimum cognitive screening measure in clinical trials of PD where cognitive performance is not the primary outcome measure. The MoCA still requires further study of its diagnostic utility in PD populations but appears to be the most appropriate measure among the currently available brief cognitive assessments. Widespread adoption of a single instrument such as the MoCA in clinical trials can improve comparability between research studies on PD.

Impact of the "polytrauma clinical triad" on sleep disturbance in a department of veterans affairs outpatient rehabilitation setting.

Lew HL, Pogoda TK, Hsu P-T, Cohen S, Amick MM, Baker E, Meterko M, Vanderploeg RD: Impact of the “polytrauma clinical triad” on sleep disturbance in a Department of Veterans Affairs outpatient rehabilitation setting. Objective:There is a high prevalence of Operation Enduring Freedom/Operation Iraqi Freedom veterans returning with the “polytrauma clinical triad” of pain, posttraumatic stress disorder, and traumatic brain injury. This study examined the effect of the polytrauma clinical triad on sleep disturbance, defined as difficulty falling or staying asleep, a common problem in Operation Enduring Freedom/Operation Iraqi Freedom veterans. Design:A chart review was conducted for 200 Operation Enduring Freedom/Operation Iraqi Freedom veterans evaluated at a polytrauma outpatient clinic. Data that were abstracted included a sleep disturbance severity index, diagnoses of posttraumatic stress disorder and traumatic brain injury, and reported problems of pain. Results:Sleep disturbance was highly prevalent (93.5%) in this sample, in which the majority of traumatic brain injury diagnoses were mild. In the multiple regression analysis, posttraumatic stress disorder, pain, the interaction of traumatic brain injury and posttraumatic stress disorder, and the interaction of posttraumatic stress disorder and pain significantly accounted for sleep disturbance. As a separate independent variable, traumatic brain injury was not associated with sleep disturbance. Conclusions:Our preliminary results showed that posttraumatic stress disorder and pain significantly contributed to sleep disturbance. When traumatic brain injury or pain coexisted with posttraumatic stress disorder, sleep problems worsened. In this clinical population, where the majority of traumatic brain injury diagnoses tend to be in the mild category, traumatic brain injury alone did not predict sleep disturbance. Through increased awareness of pain, posttraumatic stress disorder, and traumatic brain injury, clinicians can work collaboratively to maximize rehabilitation outcomes.

Computerized Maze Navigation and On-Road Performance by Drivers With Dementia

This study examined the ability of computerized maze test performance to predict the road test performance of cognitively impaired and normal older drivers. The authors examined 133 older drivers, including 65 with probable Alzheimer disease, 23 with possible Alzheimer disease, and 45 control subjects without cognitive impairment. Subjects completed 5 computerized maze tasks employing a touch screen and pointer as well as a battery of standard neuropsychological tests. Parameters measured for mazes included errors, planning time, drawing time, and total time. Within 2 weeks, subjects were examined by a professional driving instructor on a standardized road test modeled after the Washington University Road Test. Road test total score was significantly correlated with total time across the 5 mazes. This maze score was significant for both Alzheimer disease subjects and control subjects. One maze in particular, requiring less than 2 minutes to complete, was highly correlated with driving performance. For the standard neuropsychological tests, highest correlations were seen with Trail Making A (TrailsA) and the Hopkins Verbal Learning Tests Trial 1 (HVLT1). Multiple regression models for road test score using stepwise subtraction of maze and neuropsychological test variables revealed significant independent contributions for total maze time, HVLT1, and TrailsA for the entire group; total maze time and HVLT1 for Alzheimer disease subjects; and TrailsA for normal subjects. As a visual analog of driving, a brief computerized test of maze navigation time compares well to standard neuropsychological tests of psychomotor speed, scanning, attention, and working memory as a predictor of driving performance by persons with early Alzheimer disease and normal elders. Measurement of maze task performance appears to be useful in the assessment of older drivers at risk for hazardous driving.

A double-blind comparison of galantamine hydrobromide ER and placebo in Parkinson disease

Objective: To study the efficacy and safety of galantamine hydrobromide ER for the enhancement of cognition in non-demented Parkinson’s patients (PD). Methods: Sixty-nine non-demented PD participants were randomised in a double-blind, placebo-controlled study of galantamine or placebo. Galantamine was administered over 16 weeks (8 mg/day for 4 weeks, a therapeutic dose of 16 mg/day for 6 weeks and a maximum dose of 24 mg/day for 6 weeks). Outcome measures were neuropsychological (attention, verbal fluency, executive, memory, visuospatial), behavioural (Frontal Systems Behavior Scale, Neuropsychiatric Inventory-Questionnaire, PDQ-39) and motor (Unified Parkinson’s Disease Rating Scale motor scale). Results: 26 individuals on active medication and 28 individuals on placebo were included in the outcome analyses. No significant differences were found between the active and placebo groups on cognitive, behavioural or motor outcome measures. Most common adverse events were gastrointestinal and self-reported worsening of PD symptoms. Conclusions: Contrary to our hypotheses, galantamine treatment did not improve attention/executive, memory or visuospatial performance in non-demented PD patients. Further, there was a high, statistically significant drop-out rate in the treatment group due to gastrointestinal side effects and self-reported worsening of PD symptoms. Treatment with galantamine did not enhance self-perception of mental sharpness or quality of life. No negative behavioural change such as hallucinations or apathy was found with treatment.

Visual processing of rapidly presented stimuli is normalized in Parkinson's disease when proximal stimulus strength is enhanced.

Deficient perception and cognition in Parkinsons disease (PD) has been attributed to slow information processing, but an alternative explanation may be reduced signal strength. In 18 nondemented individuals with PD and 15 healthy adults, we enhanced the contrast level of rapidly flashed masked letters. The PD group required significantly higher contrast to reach criterion (80% accuracy). Normal motion detection in these participants indicated no gross, general dysfunction of the dorsal visual processing stream. These results suggest that putatively slowed processing in PD may be an artifact of reduced signal strength arising from depletion of dopamine in retina or cortical visual areas.

ROLE OF A LATERALIZED PARIETAL-BASAL GANGLIA CIRCUIT IN HIERARCHICAL PATTERN PERCEPTION: EVIDENCE FROM PARKINSON’S DISEASE

The role of corticostriatal circuits in hierarchical pattern perception was examined in Parkinsons disease. The hypothesis was tested that patients with right-side onset of motor symptoms (RPD, left hemisphere dysfunction) would be impaired at local level processing because the left posterior temporoparietal junction (TP) emphasizes processing of local information. By contrast, left-side onset patients (LPD; right hemisphere dysfunction) would show impaired global processing because right TP emphasizes global processing. Participants identified targets at local or global levels without and with attention biased toward those levels. Despite normal attentional control between levels, LPD patients showed a single dissociation, demonstrating abnormal global level processing under all conditions, whereas RPD patients showed abnormal local level processing mainly when attention was biased toward the local level. These findings link side of motor symptom onset to visuospatial cognitive abilities that depend upon the contralateral TP, highlighting that side of onset can predict visuospatial impairments, and provide evidence that an inferior parietal-basal ganglia pathway involving the caudate head and the hemispherically asymmetrical TP region is necessary for hierarchical pattern perception.

Body side of motor symptom onset in Parkinson's disease is associated with memory performance

The relation of body side of motor symptom onset in Parkinsons disease (PD) to memory measures associated with hemispheric dominance was examined. Fourteen patients with right body side motor symptom onset (RPD, inferred left hemisphere dysfunction) and 16 patients with left side onset (LPD, right hemisphere dysfunction) were administered measures of verbal (Hopkins Verbal Learning Test-Revised) and visual memory (Brief Visual Memory Test-Revised), that require similar task demands and are associated with left or right hemisphere dominance, respectively. The LPD group demonstrated poorer visual than verbal memory, both within group and in comparison to the RPD group. By contrast, the RPD group showed poorer verbal than visual memory within group. These findings suggest that side of motor symptom onset is associated with asymmetrical memory dysfunction.

Non-Motor Aspects of Parkinson's Disease

Parkinsons disease is primarily considered to be a movement disorder and is defined by its motor signs. Yet, the behavioral manifestations of the disease are often more debilitating than its motor complications. This review will focus on the non-motor aspects of Parkinsons disease, including mood, psychosis, cognitive, sleep, fatigue, apathy, delirium, and repetitive disorders, that may occur. The phenomenology, pathology, and treatment of the behavioral symptoms of Parkinsons disease will be discussed.