Gregory P. Crucian

The MoCA Well-suited screen for cognitive impairment in Parkinson disease

Objective: To establish the diagnostic accuracy of the Montreal Cognitive Assessment (MoCA) when screening externally validated cognition in Parkinson disease (PD), by comparison with a PD-focused test (Scales for Outcomes in Parkinson disease–Cognition [SCOPA-COG]) and the standardized Mini-Mental State Examination (S-MMSE) as benchmarks. Methods: A convenience sample of 114 patients with idiopathic PD and 47 healthy controls was examined in a movement disorders center. The 21 patients with dementia (PD-D) were diagnosed using Movement Disorders Society criteria, externally validated by detailed independent functional and neuropsychological tests. The 21 patients with mild cognitive impairment (PD-MCI) scored 1.5 SD or more below normative data in at least 2 measures in 1 of 4 cognitive domains. Other patients had normal cognition (PD-N). Results: Primary outcomes using receiver operating characteristic (ROC) curve analyses showed that all 3 mental status tests produced excellent discrimination of PD-D from patients without dementia (area under the curve [AUC], 87%–91%) and PD-MCI from PD-N patients (AUC, 78%–90%), but the MoCA was generally better suited across both assessments. The optimal MoCA screening cutoffs were <21/30 for PD-D (sensitivity 81%; specificity 95%; negative predictive value [NPV] 92%) and <26/30 for PD-MCI (sensitivity 90%; specificity 75%; NPV 95%). Further support that the MoCA is at least equivalent to the SCOPA-COG, and superior to the S-MMSE, came from the simultaneous classification of the 3 PD patient groups (volumes under a 3-dimensional ROC surface, chance = 17%: MoCA 79%, confidence interval [CI] 70%–89%; SCOPA-COG 74%, CI 62%–86%; MMSE-Sevens item 56%, CI 44%–68%; MMSE-World item 62%, CI 50%–73%). Conclusions: The MoCA is a suitably accurate, brief test when screening all levels of cognition in PD.

Limb-kinetic apraxia in Parkinson disease

To learn if limb-kinetic apraxia (LKA) is associated with Parkinson disease (PD), participants with PD (on medications) and control subjects performed finger tapping (FT), measuring movement speed, and performed coin rotation (CR), measuring precise coordinated but independent finger movements and speed. There were no group differences in FT, a measure of bradykinesia–rigidity, but CR rotation was impaired in PD. Thus, LKA, not related to bradykinesia–rigidity, is associated with PD.

Neglect after right hemisphere stroke A smaller floodlight for distributed attention

Objective: To learn whether there was a defect in an attentional floodlight. We used a line decision task for which subjects had to decide if two line segments separated by a gap were one line or two parallel lines. We varied the area of the gap and, therefore, the area over which subjects needed to spread attention to perform the task correctly. Background: Visual tasks requiring focused attention use an attentional spotlight. Other visual tasks requiring spatially distributed attention may require a floodlight. Neglect after right hemisphere stroke can be associated with a defect in the attentional spotlight. Results and Conclusions: Two patients with neglect after right hemisphere stroke performed more poorly than normal control subjects and left hemisphere-damaged control subjects as the area of spread in the gap increased. Right hemisphere-damaged patients did not differ from control subjects performance on another visuospatial parameter-the degree of discontinuity between the line segments. These results support a defective attentional floodlight in neglect.

Emotional conversations in Parkinson’s disease

Objective: To learn how PD influences verbal description of emotional events. Background: Individuals with PD exhibit emotional processing deficits. Emotional experience likely involves several dimensions (e.g., valence, arousal, motor activation) subserved by a distributed modular network involving cortical, limbic, basal ganglia, diencephalic, and mesencephalic regions. Although the neurodegeneration in PD likely affects components in this network, little is known about how PD influences emotional processing. Because PD is associated with activation deficits, one could predict that the discourse of emotional experiences involving high activation would be reduced in patients with PD compared to control subjects. Alternatively, because patients with PD exhibit paradoxical sensitivity to externally evoked motor activation (kinesia paradoxica), it is possible that emotional stimuli may facilitate verbal emotional expression more so in patients with PD than in control subjects. Methods: The authors measured verbal descriptions of personal emotional experiences in subjects with PD and normal controls. Results: Compared with control subjects, individuals with PD showed a relative increase in the number of words spoken and in discourse duration when talking about emotional experiences that are usually associated with high levels of arousal and motor activation. Although the authors did not measure arousal or activation, prior research has shown that, when asked to recall an emotional experience, people will often re-experience the emotion previously experienced during that episode. Conclusions: Recalling emotional episodes induces verbal kinesia paradoxica in patients with PD. Although recall of these emotional episodes may have been associated with increased arousal and activation, the mechanism underlying emotional verbal kinesia paradoxica is unclear.

Anxiety and depression severity are related to right but not left onset Parkinson's disease duration

Depression and anxiety have both been associated with relative left frontal hypoactivation and the motor symptoms of Parkinsons disease typically begin in a lateral or asymmetrical fashion. Hence, PD patients with right hemibody onset may experience heightened depression and anxiety. However, research is mixed regarding whether right or left hemibody onset PD is associated with elevated levels of depression and anxiety. This literature, though, has not considered the potential moderating variable of disease duration. We hypothesized that disease duration would be positively correlated with measures of depression and anxiety in right but not left hemibody onset PD patients. The results indicated that scores on the Geriatric Depression Scale, Beck Depression Inventory-II, and the State Trait Anxiety Scale - State correlated positively with disease duration, but only in the right hemibody onset group of PD patients. Thus, right hemibody onset PD is associated with more severe depressive and anxiety symptoms, but only when disease duration is considered.

Emotional Influences on Spatial Attention

The relationships between the anterior-posterior and left-right regions of the brain have been characterized as mutually inhibitory. Whereas the left hemisphere attends to right proximal hemispace and is associated with positive emotions, the right hemisphere attends to left distal hemispace and is associated with negative emotions. Because of the excitatory and inhibitory influences between the left and right frontal and posterior regions of the brain, the expression of emotion will result in an ipsilateral attentional bias. Given these functional systems, we hypothesized that positive emotions would be associated with a bias for left distal hemispace and negative emotions would be associated with a bias for right proximal hemispace. We tested these hypotheses by having 138 undergraduate students place emotionally labeled pegs on a large board. Our results indicated that the positively labeled pegs were placed in left distal hemispace and the relative placement of negatively labeled pegs was rightward and proximally. Whereas numerous research investigations have examined how attention is biased for emotional stimuli, ours is the first investigation to provide evidence that emotions can bias attentional allocation.

What’s inside the art? The influence of frontotemporal dementia in art production

We evaluated the productions of an artist with frontotemporal lobar degeneration from before dementia onset until she was fully symptomatic. We noted an improvement of technique that might be related to sparing and disinhibition of the right posterior neocortex. There was a reduction of closure (completeness of the painting), possibly induced by impersistence and a decrease in evocative impact that might be explained by frontal and anterotemporal-limbic dysfunction.

Seeing trees but not the forest Limited perception of large configurations in PD

Objective: To learn if Parkinson’s disease (PD) is associated with a restricted attentional “floodlight.” Background: Different visual tasks may have different attentional requirements. Focused attention may be needed for some tasks; other tasks demand spatially distributed attention. Neglect after right cortical injury and dopamine depletion may limit the area over which attention can be spread. Although subjects with PD have dopamine depletion and can perform poorly on tests of visuospatial function, it is unclear if their attentional floodlight is restricted. Methods: Eleven subjects with PD and 11 control subjects viewed different-sized letters on five printed stimulus sheets, 43 × 56 cm. On each sheet, four different large letters (14 cm2) were composed of four different medium-sized letters (2.5 cm2), which in turn were composed of four different small letters (0.4 cm2). Stimulus sheets were presented at 30- and 75-cm viewing distances. Subjects named “all the letters they could see.” Results: Subjects with PD named small- and medium-sized letters comparably to control subjects, but PD subjects named fewer large letters than control subjects (control = 65.68%, PD = 24.55%; group-by-letter-size interaction, p < 0.05). Subjects with PD who had undergone stereotactic pallidotomy named more letters than prepallidotomy PD subjects (p = 0.05). Conclusions: PD may affect the patient’s ability to perceive large spatial configurations. As global configurations in subjects may be perceived preferentially over local patterns, it is possible that DA depletion induces an aberrant perceptual–attentional bias, such that patients have a narrowed attentional floodlight.

The Gerstmann syndrome in Alzheimer's disease

Background: It remains unclear from lesion studies whether the four signs of the Gerstmann syndrome (finger agnosia, acalculia, agraphia, and right-left confusion) cluster because the neuronal nets that mediate these activities have anatomical proximity, or because these four functions share a common network. If there is a common network, with degeneration, as may occur in Alzheimers disease, each of the signs associated with Gerstmanns syndrome should correlate with the other three signs more closely than they correlate with other cognitive deficits. Methods: Thirty eight patients with probable Alzheimers disease were included in a retrospective analysis of neuropsychological functions. Results: The four Gerstmanns syndrome signs did not cluster together. Finger naming and calculations were not significantly correlated. Right-left knowledge and calculations also did not correlate. Conclusions: The four cognitive functions impaired in Gerstmanns syndrome do not share a common neuronal network, and their co-occurrence with dominant parietal lobe injuries may be related to the anatomical proximity of the different networks mediating these functions.

Cognitive decline tracks motor progression and not disease duration in Parkinson patients

We performed an analysis of prospectively-acquired cross sectional data on 106 Parkinson disease (PD) patients who underwent comprehensive neuropsychological testing and the Unified Parkinson Disease Rating Scale (UPDRS) motor scale. A significant correlation between the UPDRS motor and neuropsychological tests in all cognitive domains except for general intelligence and visuo-spatial function was seen. In this study, cognitive decline within this PD cohort correlated with motor impairment but not disease duration. Our findings suggest that overall cognitive impairment (except visuospatial dysfunction) may track motor progression in PD more than duration of disease. Longitudinal studies are needed to confirm our results.