Sex differences in Parkinson disease-associated episodic memory and processing speed deficits.

OBJECTIVES: This study aims to address a gap in the data on cognitive sex differences in persons living with Parkinson disease (PD). There is some evidence that cognitive dysfunction is more severe in male PD, however data on episodic memory and processing speed is incomplete. METHODS: One hundred and sixty-seven individuals with a diagnosis of PD were included in this study. Fifty-six of those individuals identified as female. The California Verbal Learning Test 1st edition and the Wechsler Memory Scale 3rd edition were used to evaluate verbal and visuospatial episodic memory and the Wechsler Adult Intelligence Scale 3rd edition was used to evaluate processing speed. Multivariate analysis of covariance was used to identify sex-specific differences across groups. RESULTS: Our results show that males with PD performed significantly worse than females in verbal and visuospatial recall as well as a trend for the processing speed task of coding. CONCLUSIONS: Our finding of superior performance among females with PD in verbal episodic memory is consistent with reports in both healthy and PD individuals; however, females outperforming males in measures of visuospatial episodic memory is unique to PD. Cognitive deficits preferentially affecting males appear to be associated with frontal lobe-related function. Therefore, males may represent a disease subgroup more susceptible to disease mechanisms affecting frontal lobe deterioration and cognitive disturbances in PD.

Premonitory Urge for Tics Scale (PUTS): replication and extension of psychometric properties in youth with chronic tic disorders (CTDs).

Individuals with chronic tic disorders (CTDs) frequently describe aversive subjective sensory sensations that precede their tics. The first aim of the present study was to explore the psychometric properties of a standardized self-report measure to assess premonitory urges in CTDs, The Premonitory Urge for Tics Scale (PUTS), by replicating the analyses of Woods et al. (J Dev Behav Pediatr 26:397-403, 2005) using a sample twice the size of theirs. The second aim was to conduct an exploratory factor analysis of the PUTS. Eighty-four youth with CTDs, recruited from a pediatric OCD and tic specialty clinic, completed the PUTS while their caregivers completed The Parent Tic Questionnaire (PTQ) and a demographic measure. Consistent with (Woods et al. J Dev Behav Pediatr 26:397-403, 2005), the PUTS was found to be internally consistent (α = 0.82) and significantly correlated with overall tic severity as measured by the PTQ (r = 0.24, p < 0.05) as well as the PTQ number (r = 0.34, p < 0.01) and intensity (r = 0.24, p < 0.05) subscales. A factor-analysis of the PUTS revealed a two-factor solution with one factor capturing the quality of premonitory sensations while the other factor assessed the overall intensity of the urges. These results support the use of the PUTS in reliably measuring premonitory urges, particularly in children over the age of 10 years. Additionally, these findings highlight that urges are uniformly reported across gender and age and are more closely associated with number of tics than the frequency or intensity of tics.

Construct validity of the Functional Assessment of Verbal Reasoning and Executive Strategies (FAVRES).

BACKGROUND: The Functional Assessment of Verbal Reasoning and Executive Strategies (FAVRES) is a measure of cognitive-communication and executive functions involving everyday tasks. Scores are predictive of employment status; however, the measure's construct validity is unclear. OBJECTIVE: The study's objective was to assess the linear association of FAVRES test performance with performance on a number of neuropsychological measures in a sample of individuals with neurocognitive deficits. METHODS: Twenty-two adults completed the FAVRES, Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), Delis-Kaplan Executive Function System (D-KEFS), Color-Word Interference (CWI), Tower and Trail Making (TM). RESULTS: FAVRES Total Accuracy score significantly correlated with CWI Inhibition (r = -0.43) and Tower (r = 0.60). Total Rationale significantly correlated with CWI Inhibition (r = -0.49), TM Number-Letter Switching (r = -0.48) and Tower (r = 0.55). Total Reasoning significantly correlated with CWI Inhibition (r = -0.71), Inhibition Switching (r = -0.50), TM Number-Letter Switching (r = -0.67) and Tower (r = 0.69) but also correlated with a number of measures involving other elements of cognition. CONCLUSION: Results provide evidence of convergent validity for the FAVRES as a measure of executive functions. Accuracy and Rationale scores also appear to have good discriminant validity.

Preliminary Evidence That Design Fluency Is Related to Dual-Task Treadmill Gait Variability in Healthy Adults.

Evidence supporting a link between gait and cognition is accumulating. However, the relation between executive functioning and spatiotemporal gait parameters has received little attention. This is surprising since these gait variables are related to falls. The goal of this preliminary study was to determine whether performance on measures of inhibition, reasoning, and fluency is related to variability in stride length and step width during dual-task treadmill walking in a sample of healthy adults. Nineteen healthy adults averaging 40 years of age were evaluated. Results indicated that processing speed was reduced, t(18) = 6.31, p = 0.0001, step width increased, t(18) = -8.00, p = 0.0001, and stride length decreased, t(18) = 3.06, p = 0.007, while dual tasking, but variability in gait parameters did not significantly change, consistent with a gait/posture-first approach. As hypothesized, better performance on a visual design fluency task which assesses cognitive flexibility was associated with less dual-task stride length variability, rs (17) = -0.43, p = 0.034, and step width variability, r = -0.56, p = 0.006. The results extend previous findings with older adults walking over ground and additionally suggest that cognitive flexibility may be important for gait maintenance while dual tasking.

Neuroticism and Extraversion Are Related to Changes in Postural Stability During Anatomically-Related Cognitive Tasks.

The relationship between personality and postural stability has received little attention. This study addressed whether neuroticism and extraversion correlate with changes in postural stability while performing cognitive tasks related to brain regions selectively associated with neuroticism and extraversion. Thirty-two adults stood on a foam mat in tandem stance and completed a 2-back task and a weather prediction task (WPT). As predicted, higher neuroticism was related to increased dual task sway during the 2-back task, r = 0.40, p = 0.023, and lower extraversion was related to increased dual task sway during the WPT, r = -0.43, p = 0.013, suggesting that personality is related to postural stability in healthy young adults and that personality could be considered in the prediction and treatment of individuals with balance difficulties.

Predictors of HVOT performance in Parkinson's disease.

Evidence suggests that the Hooper Visual Organization Test (HVOT) has naming and executive components that vary in size depending on neurological diagnosis. The current study used a sample of individuals with Parkinson's disease (PD) to demonstrate for the first time that an executive measure can be the best predictor of HVOT performance. Forty-eight nondemented and nondepressed individuals with idiopathic PD completed the HVOT and other measures of visuoperception, executive function, and visual confrontation naming. Despite average performance on all neuropsychological measures, an executive measure, time to complete Trail-Making Test Part B minus time to complete Part A, was clearly the best predictor of HVOT performance in a standard regression. The pattern of neurocognitive predictors is unlike that reported in healthy individuals and other patient samples. This finding suggests that the presence of a neuropathological process can alter neurocognitive correlates even when performance is intact, and supports the contention that executive function is paramount in the cognitive profile associated with PD.

Cellular Telephone Dialing Influences Kinematic and Spatiotemporal Gait Parameters in Healthy Adults.

Gait speed is typically reduced when individuals simultaneously perform other tasks. However, the impact of dual tasking on kinetic and kinematic gait parameters is unclear because these vary with gait speed. The objective of this study was to identify whether dual tasking impacts gait in healthy adults when speed is constant. Twenty-two healthy adults dialed a cell phone during treadmill walking at a self-selected speed while kinetic, kinematic, and spatial parameters were recorded. Results indicated that dual tasking did not impact phone dialing speed, but increased stride width, peak knee flexion during stance, and peak plantarflexion, and decreased knee and ankle range of motion. Dual tasking appears to influence kinematic gait variables in a manner consistent with promotion of stability.

A sex comparison of reactive knee stiffness regulation strategies under cognitive loads.

BACKGROUND: Sex differences may exist in cognitive faculties and neuromuscular strategies for maintaining joint stability. The purpose of this study was to assess whether preparatory and reactive knee stiffening strategies are affected differently in males and females exposed to sex-biased cognitive loads. METHODS: 20 male and 20 female volunteers were tested for knee joint stiffness and quadriceps and hamstring muscle activation patterns throughout a rapid eccentric knee extension perturbation. Participants were tested under 3 cognitive loads (Benton's Judgment of Line Orientation; Symbol Digit modalities Test; and Serial 7's) and a control condition. Apparent knee joint stiffness and muscle activation amplitude and timing were quantified throughout the perturbation across the 4 conditions. FINDINGS: Reactive knee stiffness values were significantly less during the cognitive tasks compared to the control condition (Judgment of Line Orientation=0.034Nm/deg/kg, Symbol Digit Modalities Test=0.037Nm/deg/kg, Serial 7's=0.037Nm/deg/kg, control=0.048Nm/deg/kg). Females had greater normalized total apparent stiffness than males. The quadriceps muscles had faster and greater activation than the hamstring muscles; however, no group differences were observed. No overall differences in muscle activation (magnitude and timing) were found between the cognitive loading tasks. INTERPRETATION: Cognitive loading may decrease the ability of healthy individuals to reactively stiffen their knee joint and appears to interfere with the normal stiffness regulation strategies. This may elucidate an extrinsic risk factor for non-contact knee ligament injury.

Dopamine dependency of cognitive switching and response repetition effects in Parkinson's patients.

A group of people with Parkinson's disease and a group of matched controls were tested on a task involving a switch between perceptual dimensions. Patients were tested both 'on' and 'off' their normal medication cycles. Stimuli appeared in pairs for each trial, with each stimulus consisting of a color and a shape. One dimension of color and one of shape were mapped to each of two response keys. A cue was presented concurrently with each stimulus to indicate whether to respond on the basis of color or shape, following procedures developed by Hayes et al. [Hayes, A.E., Davidson, M.C., Keele, S.W., and Rafal, R.D. (1998). Toward a functional analysis of the basal ganglia. Journal of Cognitive Neuroscience, 10, 178-198]. Replicating previous literature, abnormally large switch costs were observed in patients who were off their normal medication cycles. A novel finding was that patients in the 'on' state demonstrated a slight reversal of switch costs. Also novel, reaction time (RT) costs associated with switching between response keys, and interactions between response switching and task switching were influenced predominantly by on-off dopamine manipulations. It is concluded that abnormal task switching costs and response repetition effects likely reflect impairments of activation and inhibition, and both effects are dopamine-dependent.

Subjective Cognitive Complaints in Parkinson Disease Without Dementia: A Preliminary Study.

Little is known about the subjective cognitive complaints of individuals with Parkinson disease (PD). Such complaints have become a topic of interest recently as they play a role in the diagnosis of neurocognitive disorders. The aim of this preliminary study was to determine whether a sample of nondemented individuals with PD reported significantly more difficulties with multiple elements of cognition than a control sample and to assess the relation between their ratings and demographics, motor symptom severity, neuropsychological test performance, and measures of depression and anxiety. Forty nondemented individuals with PD and 27 healthy individuals completed a questionnaire assessing everyday cognitive difficulties. Independent t tests indicated that individuals with PD reported significantly more cognitive complaints in general and in specific tasks involving complex attention, executive function, processing speed, and verbal fluency but not memory. Questionnaire ratings significantly correlated with measures assessing anxiety, verbal memory, processing speed, and verbal fluency. Results suggest that it is important to ask individuals with PD about cognitive complaints across several cognitive domains and also inquire about symptoms of anxiety, which may be related to their self-reported cognitive difficulties.

Walking stability during cell phone use in healthy adults.

The number of falls and/or accidental injuries associated with cellular phone use during walking is growing rapidly. Understanding the effects of concurrent cell phone use on human gait may help develop safety guidelines for pedestrians. It was shown previously that older adults had more pronounced dual-task interferences than younger adults when concurrent cognitive task required visual information processing. Thus, cell phone use might have greater impact on walking stability in older than in younger adults. This study examined gait stability and variability during a cell phone dialing task (phone) and two classic cognitive tasks, the Paced Auditory Serial Addition Test (PASAT) and Symbol Digit Modalities Test (SDMT). Nine older and seven younger healthy adults walked on a treadmill at four different conditions: walking only, PASAT, phone, and SDMT. We computed short-term local divergence exponent (LDE) of the trunk motion (local stability), dynamic margins of stability (MOS), step spatiotemporal measures, and kinematic variability. Older and younger adults had similar values of short-term LDE during all conditions, indicating that local stability was not affected by the dual-task. Compared to walking only, older and younger adults walked with significantly greater average mediolateral MOS during phone and SDMT conditions but significantly less ankle angle variability during all dual-tasks and less knee angle variability during PASAT. The current findings demonstrate that healthy adults may try to control foot placement and joint kinematics during cell phone use or another cognitive task with a visual component to ensure sufficient dynamic margins of stability and maintain local stability.

Everyday executive function impairments predict comorbid psychopathology in autism spectrum and attention deficit hyperactivity disorders.

OBJECTIVE: Autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) both have psychiatric comorbidities and distinctive profiles of executive dysfunction. Although there is evidence that executive function (EF) plays a role in the expression of specific behaviors and psychiatric symptoms, it is not known whether specific EF deficits in ASD and ADHD may be pathways to comorbidities in the disorders. This study examines whether parent reported problems with flexibility in ASD and inhibition in ADHD mediate the disorders' associations with anxiety/depression and oppositional/aggressive behavior, respectively. METHOD: Parent report data from the Behavior Rating Inventory of Executive Function (BRIEF) and the Child Behavior Checklist (CBCL) were obtained for 125 children (70 ASD, 55 ADHD Hyperactive/Impulsive or Combined type) as part of a neuropsychological assessment. Diagnostic status, BRIEF Shift (shifting/flexibility) and Inhibit (behavioral inhibition) scale scores, and CBCL Anxious/Depressed (anxiety/depression) and Aggressive Behavior (oppositionality/aggression) scale scores were analyzed with a path analysis to investigate the relation of flexibility and inhibition to comorbid symptoms in children with ASD and ADHD. RESULTS: In a path model with good fit ASD predicted greater inflexibility which predicted greater anxiety/depression, while ADHD predicted greater disinhibition that predicted greater aggression, consistent with our mediational hypotheses. Unexpectedly, the greater inflexibility associated with ASD also predicted greater aggression. CONCLUSIONS: Findings support the importance of everyday EF problems in ASD and ADHD as predictors of comorbid psychopathology and as crucial intervention targets for potential prevention and mitigation of comorbid symptoms.

Contributing factors to depressed mood in Multiple Sclerosis.

By applying the behavioral theory of Lewinsohn et al. [1985. An integrative theory of depression. In: S. Reiss, & R. R. Bootzin (Eds.), Theoretical issues in behavior therapy (pp. 331-359). San Diego, CA: Academic Press.] to multiple sclerosis (MS), it was hypothesized that physical disability, fatigue, and psychosocial dysfunction would be significantly predictive of depressed mood in MS patients. Seventy-six MS patients completed the following measures: the Sickness Impact Profile (SIP), the Fatigue Impact Scale (FIS), and the mood subscale from the Chicago Multiscale Depression Inventory (CMDI). Structural equation modeling revealed that physical disability and fatigue were indirectly predictive of depressed mood via their effects on recreational functioning. Fatigue also had a direct effect on mood. If reductions in recreational activities actually cause decrements in mood, depressed mood in MS may be treatable by helping patients identify recreational activities that they can enjoy regardless of physical or fatigue-related difficulties.

Perceived and performance-based executive dysfunction in Parkinson's disease.

Executive dysfunction is common in early stage Parkinson's disease (PD). We evaluated the relationship between self- and informant-report measurement of real-world executive functions as well as performance-based neuropsychological measures in mildly cognitively impaired individuals with PD and healthy controls. The PD group reported more difficulty with initiation of complex tasks compared to caregiver ratings, and processing speed was a strong predictor of self-reported executive dysfunction for the PD group, followed by depression. Processing speed and semantic verbal fluency predicted informant-reported executive dysfunction in PD. These findings highlight the contribution of speeded processing for performance of everyday executive tasks in PD.

The contribution of trail making to the prediction of performance-based instrumental activities of daily living in Parkinson's disease without dementia.

Performance on Part B of the Trail Making Test (TMT) contributes to the prediction of ability to complete instrumental activities of daily living (IADLs) in Parkinson's disease (PD). Although this suggests that cognitive flexibility is important in the everyday functioning of individuals with PD, this may not be the case as the TMT is multifactorial, involving motor speed, visual scanning, sequencing, and cognitive flexibility. The purpose of the current study was to determine which elements of the task contribute to the prediction of IADLs in a sample of 30 nondemented individuals with PD. Correlational analyses indicated strong relationships between a performance-based measure of IADLs and measures involving scanning, sequencing, and cognitive flexibility from the Delis-Kaplan Executive Function System (D-KEFS) TMT. Results from standard regressions indicated that measures of sequencing and level of depression but not scanning, cognitive flexibility, or demographic variables made a significant, independent contribution to the prediction of IADLs. These results suggest that the sequencing element of the TMT is paramount in the prediction of IADLs in PD.

Test-order effects: a measure of verbal memory influences performance on a measure of verbal fluency.

In neuropsychological assessment, the impact of completing one measure on the performance of a second measure is often unknown. The current study examined the effect of a list-learning measure, the California Verbal Learning Test-Second Edition (CVLT-II), on a verbal fluency measure, the Delis-Kaplan Executive Functioning System Verbal Fluency subtest, when completed in a battery of tests. These tests were chosen because stimuli from the CVLT-II can function as responses for Verbal Fluency. Twenty-eight individuals seeking psychoeducational evaluation were randomly assigned to one of two test orders: the CVLT-II followed by Verbal Fluency, or the reverse order. Consistent with hypotheses, individuals who completed the CVLT-II first used more words from this task as responses on the various Verbal Fluency tasks, t(26) = 2.84, p = .009. In addition, they obtained higher raw scores and scaled scores on Category Fluency: t(26) = 3.01, p = .006, and t(26) = 2.53, p = .018, respectively. Surprisingly, the larger number of words produced on Category Fluency exceeded the number of CVLT-II words used as responses. These results suggest that clinicians should consider the order of administration when using these measures, and they indicate a need for further investigation of order effects.

The ecological validity of clinical tests of visuospatial function in community-dwelling older adults.

Little is known about the relation between measures of visuospatial function and daily functioning in community-dwelling older adults. The current study addresses this gap in the literature. Forty individuals with mean (SD) age and education of 78.4 (7.5) and 11.9 (2.6) years, respectively, completed a battery of neuropsychological measures including traditional tests of visuospatial function, a test of visuospatial function with verisimilitude, and performance-based measures of global daily functioning and visuospatial daily functioning. Unlike previous studies, statistical analyses directly evaluated the magnitude of the correlations between cognitive tests and daily functioning. Results indicated that all visuospatial measures significantly correlated with both measures of daily functioning (rs = .34-.59). Although the measure designed with verisimilitude was not significantly better than the traditional visuospatial measures at predicting daily functioning, it did account for significant variance beyond that accounted for by the other tests, supporting its incremental validity.

Neurocognitive predictors of performance on a telephone task following stroke.

A growing body of evidence indicates that cognitive function is related to functional ability; however, little attention has been paid to which neuropsychological measures are predictive of specific daily tasks. The purpose of the current study was to determine the neurocognitive predictors of a performance-based telephone task in a sample of patients with recent stroke. A sample of 51 individuals with stroke completed a battery of neuropsychological measures and a telephone task. Regression analyses indicated that measures of visuoperception and global cognitive function were the best predictors of ability to use the telephone. Results are discussed in light of previous findings with different patient populations and different measures of functional ability.

The clinical significance of neuropsychological changes following bilateral subthalamic nucleus deep brain stimulation for Parkinson's disease.

Despite the clinical importance of the question, a number of methodological issues have limited firm conclusions regarding the cognitive safety of deep brain stimulation (DBS) of the subthalamic nucleus (STN) in Parkinson's disease (PD). Amongst these issues, studies have generally failed to consider the postoperative changes that occur within individual patients. This study utilized reliable change indices (RCIs) derived from a PD sample to determine the frequency of clinically significant postoperative decline on a battery of neuropsychological measures. This approach addresses measurement reliability, potential practice effects, and disease progression. The proportion of patients experiencing clinically significant postoperative decline on measures of list learning and verbal fluency was greater than expected based on disease progression; however, the majority of patients (55%) did not experience a significant decline in performance on any of the cognitive tests administered, and only one experienced decline on more than one test. Therefore, the statistically significant declines on measures of list learning and verbal fluency observed in the sample as a whole were the result of clinically significant declines experienced by a minority of participants.

Cognitive deficits in essential tremor consistent with frontosubcortical dysfunction.

Essential tremor (ET) is increasingly thought to involve a heterogeneous group of patients, with some also exhibiting symptoms of Parkinson's disease (PD), including cognitive deficits. The goal of this study was to utilize a broad battery of neuropsychological measures to compare the cognitive function of 33 ET patients with that of 33 matched PD patients and 21 normal controls. Results indicated that the ET group performed significantly worse than controls across multiple cognitive domains, but performed remarkably similar to PD patients, consistent with frontosubcortical dysfunction.