Clinical Features of Parkinson’s Disease in Patients with Early-Onset Freezing of Gait

Background. Freezing of gait (FOG) is an important symptom that can impair activities of daily living in patients with Parkinson’s disease (PD). However, its pathogenic mechanism is largely unknown. The aim of the present study was to elucidate the clinical characteristics of newly diagnosed and levodopa-naïve patients with PD who present with FOG. Methods. A total of 53 patients with untreated PD (29 men and 24 women) within 2 years of disease onset were included in the study. Using item 3 of the Freezing of Gait Questionnaire (FOG-Q), patients were classified as “freezers” and “nonfreezers” and compared for cognitive function, depressive symptoms, apathy, olfactory function, motor severity, gait parameters, and daily physical activity. We also assessed the relationship between FOG severity (total score of items 3–6 on the FOG-Q) and various clinical parameters. Results. The FOG was reported by 8 (15%) patients with PD. The Apathy Scale score ( $p=0.018$ ), Modified Hoehn and Yahr stage ( $p<0.001$ ), Unified Parkinson’s Disease Rating Scale part III score ( $p<0.001$ ), and postural instability and gait disorder score ( $p<0.001$ ) were significantly higher, and the mean gait acceleration amplitude ( $p=0.006$ ) was significantly lower in freezers compared to that in nonfreezers. However, there was no significant correlation between FOG severity and these clinical parameters. There was also no significant difference in cognitive function, depressive symptoms, and olfactory function between the two groups. Daily physical activity was significantly lower in freezers than that in nonfreezers. Conclusions. Since FOG develops soon after PD onset, the study findings suggest that the FOG might be associated with the severity of apathy, motor symptoms, and in particular, gait disturbance.

A Virtual Kitchen Protocol to Measure Everyday Memory Functioning for Meal Preparation

In this study, we developed the Virtual Kitchen Protocol (VKP), a virtual reality-based measure of everyday memory functioning for meal preparation tasks. We investigated the construct validity of the VKP by comparing the performance of young adults (n = 41) and older adults without (n = 52) and with (n = 7) a neurocognitive diagnosis, as well as by examining correlations with standardized measures of verbal and visual memory. The results show that young adults had higher recall than older adults and that the VKP was sensitive to neurocognitive impairment among older adults. The VKP demonstrated moderate to high correlations with other memory tests. These results support the construct validity of the VKP and suggest that it holds promise as a virtual reality-based measure of memory for meal preparation tasks.

Effects of Candesartan vs Lisinopril on Neurocognitive Function in Older Adults With Executive Mild Cognitive Impairment: A Randomized Clinical Trial

IMPORTANCE

Observational studies have suggested that angiotensin receptor blockers are associated with a unique cognitive protection. It is unclear if this is due to reduced blood pressure (BP) or angiotensin receptors type 1 blockade.

OBJECTIVE

To determine neurocognitive effects of candesartan vs lisinopril in older adults with mild cognitive impairment (MCI).

DESIGN, SETTING, AND PARTICIPANTS

This randomized clinical trial included participants aged 55 years or older with MCI and hypertension. Individuals were withdrawn from prior antihypertensive therapy and randomized in a 1 to 1 ratio to candesartan or lisinopril from June 2014 to December 2018. Participants underwent cognitive assessments at baseline and at 6 and 12 months. Brain magnetic resonance images were obtained at baseline and 12 months. This intent-to-treat study was double-blind and powered for a sample size accounting for 20% dropout. Data were analyzed from May to October 2019.

INTERVENTIONS

Escalating doses of oral candesartan (up to 32 mg) or lisinopril (up to 40 mg) once daily. Open-label antihypertensive drug treatments were added as needed to achieve BP less than 140/90 mm Hg.

MAIN OUTCOMES AND MEASURES

The primary outcome was executive function (measured using the Trail Making Test, Executive Abilities: Measures and Instruments for Neurobehavioral Evaluation and Research tool) and secondary outcomes were episodic memory (measured using the Hopkins Verbal Learning Test-Revised) and microvascular brain injury reflected by magnetic resonance images of white matter lesions.

RESULTS

Among 176 randomized participants (mean [SD] age, 66.0 [7.8] years; 101 [57.4%] women; 113 [64.2%] African American), 87 were assigned to candesartan and 89 were assigned to lisinopril. Among these, 141 participants completed the trial, including 77 in the candesartan group and 64 in the lisinopril group. Although the lisinopril vs candesartan groups achieved similar BP (12-month mean [SD] systolic BP: 130 [17] mm Hg vs 134 [20] mm Hg; P = .20; 12-month mean [SD] diastolic BP: 77 [10] mm Hg vs 78 [11] mm Hg; P = .52), candesartan was superior to lisinopril on the primary outcome of executive function measured by Trail Making Test Part B (effect size [ES] = -12.8 [95% CI, -22.5 to -3.1]) but not Executive Abilities: Measures and Instruments for Neurobehavioral Evaluation and Research score (ES = -0.03 [95% CI, -0.08 to 0.03]). Candesartan was also superior to lisinopril on the secondary outcome of Hopkins Verbal Learning Test-Revised delayed recall (ES = 0.4 [95% CI, 0.02 to 0.8]) and retention (ES = 5.1 [95% CI, 0.7 to 9.5]).

CONCLUSIONS AND RELEVANCE

These findings suggest that in older adults with MCI, 1-year treatment with candesartan had superior neurocognitive outcomes compared with lisinopril. These effects are likely independent of the BP-lowering effect of candesartan.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01984164.

Cognition, function and awareness of disease impact in early Parkinson's and Huntington's disease

Purpose: Patients with Parkinson's and Huntington's Disease (PD and HD) present impairments in cognitively challenging everyday activities. This study contrasts these two basal ganglia disorders on the ability to perform daily life- like tasks and their level of awareness regarding the disease impact on function.Methods: 19 controls, 10 early-onset PD, 20 early stage PD, and 15 early manifest HD patients were compared in the "EcoKitchen," a virtual reality task with increasing executive load, the "Behavioural Assessment of Dysexecutive Syndrome battery - BADS," and "The Adults and Older Adults Functional Assessment Inventory - IAFAI," a self-report functional questionnaire. The EcoKitchen clinical correlates were investigated.Results: All clinical groups presented slower EcoKitchen performance than controls, however, only HD patients showed decreased accuracy. HD and PD patients exhibited reduced BADS scores compared to the other study participants. Importantly, on the IAFAI, PD patients signalled more physically related incapacities and HD patients indicated more cognitively related incapacities. Accordingly, the EcoKitchen performance was significantly associated with PD motor symptom severity.Conclusions: Our findings suggest differential disease impact on cognition and function across PD and HD patients, with preserved awareness regarding disease- related functional sequelae. These observations have important implications for clinical management, research and rehabilitation.Implications for rehabilitationPatients with early stage Parkinson's and Huntington's disease have diagnosis-specific impairments in the performance of executively demanding everyday activities and, yet, show preserved awareness about the disease impact on their daily life.An active involvement of patients in the rehabilitation process should be encouraged, as their appraisal of the disease effects can help on practical decisions about meaningful targets for intervention, vocational choices, quality-of-life issues and/or specific everyday skills to boost.The EcoKitchen, a non-immersive virtual reality task, can detect and quantify early deficits in everyday-like tasks and is therefore a valuable tool for assessing the effects of rehabilitation strategies on the functional cognition of these patients.Rehabilitation efforts in the mild stages of Parkinson's and Huntington's disease should be aware of greater time needs from the patients in the performance of daily life tasks, target executive skills, and give a more prominent role to patients in symptoms report and management.

Motor planning error in Parkinson's disease and its clinical correlates

This study aimed to investigate (a) motor planning difficulty by using a two-step test in Parkinson's disease (PD) compared with age-matched healthy subjects and (b) the relationship between motor planning difficulty and clinical factors. The two-step test was performed by 58 patients with PD with Hoehn & Yahr (H&Y) stage I-IV and 110 age-matched healthy older adult controls. In the two-step test, the participants estimated the two-step distance with maximum effort. Subsequently, they performed the actual two-step trial to measure the actual maximum distance. We calculated the accuracy of the estimation (estimated distance minus actual distance). In both groups, subjects who estimated >5 cm were defined as the overestimation group, and those who estimated <5 cm over- and underestimation were defined as the non-overestimation group. The overestimation group consisted of 17 healthy older adults (15.5%) and 23 patients with PD (39.7%). The number of patients with PD with overestimation was significantly more than that of healthy controls by Chi-squared test. H&Y stage and the Unified Parkinson's Disease Rating Scale (UPDRS) part II and III scores in overestimation group in PD patients were significantly higher than those in overestimation group in PD patients. Moreover, multiple regression using H&Y stage and UPDRS parts II and III as independent variables showed that the UPDRS part II score was the only related factor for the estimation error distance. Estimation error distance was significant correlated with UPDRS parts II and III. Patients with PD easily have higher rates of motor-related overestimation than age-matched healthy controls. In addition, UPDRS parts II and III expressed ability of activities of daily living and motor function as influences on motor-related overestimation. Particularly, multiple regression indicated that UPDRS part II directly showed the ability of daily living as an essential factor for overestimation.

Characteristics of apathy in treatment-naïve patients with Parkinson's disease

INTRODUCTION

Although apathy is a common psychiatric symptom of Parkinson's disease (PD), there are many unknown aspects of its pathology. This study aimed to investigate the characteristics of apathy in treatment-naïve patients with early-stage PD.

METHODS

Fifty treatment-naïve patients with early-stage PD were divided into 1 of 2 groups-apathetic or non-apathetic-based on Starkstein Apathy Scale (AS) scores. Cognitive function, depressive symptoms, olfactory function, and motor severity were compared between the two groups using validated assessment scales. Multiple linear regression was performed to assess the association between AS scores and clinical parameters.

RESULTS

Apathy (AS score ≥16) was observed in 13 (26%) patients. Assessment scale scores (Beck Depression Inventory-Second Edition [p < .004]; modified Hoehn & Yahr stage [p = .039]; Unified Parkinson's Disease Rating Scale part III [p < .001]) were significantly higher in apathetic patients than in non-apathetic patients. Significant association between these scale scores and AS score was also evident (all p ≤ .001). There were no significant differences in the test scores derived from several other validated scales.

CONCLUSION

Apathy was observed in 26% of treatment-naïve patients with early-stage PD. Significant association between apathy and motor severity was found, suggesting that dysfunction of the dopaminergic pathway is involved in the pathology of apathy.

Effects of dopaminergic drug adjustment on executive function in different clinical stages of Parkinson's disease

BACKGROUND

Effects of dopaminergic medication on executive function in patients with Parkinson's disease (PD) are inconsistent.

OBJECTIVE

We examined the effect of dopaminergic medication on executive function in 24 drug-naïve PD patients (de novo group) and in 21 PD patients on chronic dopaminergic medication (chronic medication group).

METHODS

PD patients without dementia were included in this study. For the de novo group patients, dopaminergic medication was initiated, and the dose was increased to improve motor symptoms. For the chronic medication group patients, dopaminergic medication was adjusted to relieve clinical problems. All participants were tested prior to and at 4-7 months after the drug initiation/adjustment. Executive function was assessed by using the Behavioral Assessment of the Dysexecutive Syndrome (BADS). Motor function was assessed by using the Unified Parkinson's Disease Rating Scale (UPDRS; part III). Improvement in executive function was compared with a simultaneous change in levodopa equivalent doses (LED) of dopaminergic medication and with improvement in motor functions.

RESULTS

The mean standardized BADS scores showed no significant improvement in both the groups. In the de novo group, percent improvement in the standardized BADS scores showed a significant positive correlation with the LED, but not with percent improvement in UPDRS part III. In the chronic medication group, percent improvement in the standardized BADS scores was negatively correlated with change in the LED, but not with percent improvement in UPDRS part III. Multiple regression analysis using improvement in the standardized BADS score as a dependent variable and patient's background factors (ie, age, education, disease duration, and motor and executive assessments at baseline) as independent variable showed that improvement in the executive assessment is significantly correlated with the LED only in the de novo group.

CONCLUSION

Effects of dopaminergic drug adjustment on executive function differ according to the patient's clinical stage and depend on LED in de novo stage.

Behavioural Assessment of the Dysexecutive Syndrome (BADS): Adaptação e Evidências de Validade

Resumo As funções executivas são habilidades que permitem um indivíduo direcionar seu funcionamento cognitivo, comportamental e emocional a metas. Para avaliá-las existem poucos instrumentos ecologicamente válidos. Para superar essa limitação, foi desenvolvida a Behavioural Assessment of the Dysexecutive Syndrome (BADS). O objetivo deste estudo foi adaptar e investigar evidências de validade de conteúdo da BADS para o contexto brasileiro. Foram realizadas três traduções do instrumento, sintetizadas em uma única versão e encaminhada a três juízes. Posteriormente, a BADS foi submetida a um grupo focal (5 adultos saudáveis) e estudo-piloto (amostra clínica com 40 pacientes neurológicos, portadores de Parkinson). O cálculo do coeficiente de validade de conteúdo total foi considerado aceitável (> 0,80); e a média do coeficiente kappa para os subtestes foi de 0,55, e para o questionário foi de 0,75, moderado e sólido, respectivamente. Os dados sugerem que a BADS está apta a ser utilizada em novos estudos para a investigação de outras propriedades psicométricas, como validade de construto, fidedignidade e normatização.

Relation between Resting State Front-Parietal EEG Coherence and Executive Function in Parkinson's Disease

Objective. To assess the relation between executive dysfunction (ED) in Parkinson's disease (PD) and resting state functional connectivity evaluated using electroencephalography (EEG) coherence. Methods. Sixty-eight nondemented sporadic PD patients were assessed using the Behavioural Assessment of the Dysexecutive Syndrome (BADS) to evaluate executive function. EEG coherence in the left frontoparietal electrode pair (F3-P3) and the right frontoparietal electrode pair (F4-P4) was analyzed in the alpha and theta range. The BADS scores were compared across the coherence groups, and the multiple logistic regression analysis was performed to assess the contribution of confounders. Results. The standardized BADS score was significantly lower in the low F3-P3 coherence group in the alpha range (Mann-Whitney U test, p = 0.032), though there was no difference between F4-P4 coherence group in the alpha range, F3-P3, and F4-P4 coherence groups in the theta range and the standardized BADS score. The multiple logistic regression analysis revealed the significant relation between the F3-P3 coherence group in alpha range and age-controlled standardized BADS score (p = 0.039, 95% CI = 1.002-1.062). Conclusion. The decrease in resting state functional connectivity between the frontal and parietal cortices especially in the left side is related to ED in PD.

Relationship between Postural Deformities and Frontal Function in Parkinson's Disease

Postural deformities and executive dysfunction (ED) are common symptoms of Parkinson's disease (PD); however, the relationship between postural deformities and ED in patients with PD remains unclear. This study assessed the relationship between postural deformities and ED in patients with PD. Sixty-five patients with sporadic PD were assessed for the severity of postural deformities and executive function. The severity of postural deformities was scored using the United Parkinson's Disease Rating Scale item 28 score: no postural deformity (0), mild postural deformities (1), or severe postural deformities (2-4). Executive function was assessed using the Behavioral Assessment of the Dysexecutive Syndrome (BADS) and an age-controlled standardized BADS score <70 was defined as ED. Age-controlled standardized BADS scores were compared across the three groups using the Kruskal-Wallis test. Relationship between ED and the severity of postural deformities was assessed using the Mann-Whitney U test. Age-controlled standardized BADS score significantly differed among the three groups (P = 0.005). ED was significantly related to the severity of postural deformities (P = 0.0005). The severity of postural deformities was associated with a lower age-controlled standardized BADS score and ED, and these findings suggest that postural deformities were associated with frontal dysfunction in patients with PD.

Relation between freezing of gait and frontal function in Parkinson's disease

INTRODUCTION

Freezing of gait (FOG) is a common symptom of Parkinson's disease (PD). Although the pathophysiological mechanism of FOG is unknown, previous studies have suggested that frontal dysfunction is associated with FOG. The Behavioral Assessment of the Dysexecutive Syndrome (BADS) battery, which is wide-ranging neurological battery composed of six subtests, evaluates frontal function and is more sensitive to executive dysfunction (ED) than other tools in PD patients. This is the first study to assess the relation between FOG in the 'on' state and frontal dysfunction evaluated using BADS.

METHODS

Subjects were 65 patients with PD. Multiple logistic regression analysis was used to compare the age-controlled standardized BADS score, age, disease duration, Hoehn and Yahr (HY) stage, levodopa-equivalent daily dose, and Mini-Mental State Examination (MMSE) score across patients with FOG (n = 43) and patients without FOG (n = 22). Score on each of the six BADS subtests were compared across patients with and without FOG using the Mann-Whitney U test.

RESULTS

Multiple logistic regression analysis revealed that FOG was related to lower age-controlled standardized BADS score (P = 0.022) and higher HY stage (P = 0.009) but not to disease duration, levodopa equivalent daily dose, or MMSE score. Among the six BADS subtests, score on the Zoo Map Test, which evaluates problem solving and planning, was lower in patients with FOG than in patients without FOG.

CONCLUSION

These results support a relation between on-state FOG and frontal dysfunction in PD patients.

Intentional signal in prefrontal cortex generalizes across different sensory modalities

Biofeedback-EEG training to learn the mental control of an external device (e.g., a cursor on the screen) has been an important paradigm to attempt to understand the involvements of various areas of the brain in the volitional control and the modulation of intentional thought processes. Often the areas to adapt and to monitor progress are selected a priori. Less explored, however, has been the notion of automatically emerging activation in a particular area or subregions within that area recruited above and beyond the rest of the brain. Likewise, the notion of evoking such a signal as an amodal, abstract one remaining robust across different sensory modalities could afford some exploration. Here we develop a simple binary control task in the context of brain-computer interface (BCI) and use a Bayesian sparse probit classification algorithm to automatically uncover brain regional activity that maximizes task performance. We trained and tested 19 participants using the visual modality for instructions and feedback. Across training blocks we quantified coupling of the frontoparietal nodes and selective involvement of visual and auditory regions as a function of the real-time sensory feedback. The testing phase under both forms of sensory feedback revealed automatic recruitment of the prefrontal cortex with a parcellation of higher strength levels in Brodmann's areas 9, 10, and 11 significantly above those in other brain areas. We propose that the prefrontal signal may be a neural correlate of externally driven intended direction and discuss our results in the context of various aspects involved in the cognitive control of our thoughts.

Behavioral Assessment of the Dysexecutive Syndrome for Children: an examination of clinical utility for children with attention-deficit hyperactivity disorder (ADHD)

The present study evaluated the utility of the Behavioral Assessment of Dysexecutive Syndrome for Children for discerning differences in executive functioning between attention-deficit hyperactivity disorder (ADHD) children and normal controls and examined its associations with real-life executive function as rated by parent reports on the Dysexecutive Questionnaire for Children. Sixty-three children diagnosed with ADHD and 60 normal healthy peers were recruited for this study. All participants completed the Behavioral Assessment of Dysexecutive Syndrome for Children, while their parents completed the Dysexecutive Questionnaire for Children. Results revealed that the ADHD group exhibited significantly poorer performance than the controls on 3 subtests of the Behavioral Assessment of Dysexecutive Syndrome for Children (ie, Playing Cards Test, Water Test, and Zoo Map Test 2), as well as on the total Dysexecutive Questionnaire for Children. Significant correlation was found between the total Dysexecutive Questionnaire for Children and the 6-Part Test. Findings suggested that some subtests of the Behavioral Assessment of Dysexecutive Syndrome for Children were particularly useful for detecting real-life executive dysfunction in ADHD. Yet, further studies are needed to provide extended validity data.

Barriers to exercise in people with Parkinson disease

BACKGROUND

Exercise is known to reduce disability and improve quality of life in people with Parkinson disease (PD). Although barriers to exercise have been studied in older adults, barriers in people with chronic progressive neurological diseases, such as PD, are not well defined.

OBJECTIVE

The purpose of this study was to identify perceived barriers to exercise in people with PD.

DESIGN

The study had a cross-sectional design.

METHODS

People who had PD, dwelled in the community, and were at stage 2.4 on the Hoehn and Yahr scale participated in this cross-sectional study (N=260; mean age=67.7 years). Participants were divided into an exercise group (n=164) and a nonexercise group (n=96). Participants self-administered the barriers subscale of the Physical Fitness and Exercise Activity Levels of Older Adults Scale, endorsing or denying specific barriers to exercise participation. Multivariate logistic regression analysis was used to examine the contribution of each barrier to exercise behavior, and odds ratios were reported.

RESULTS

Three barriers were retained in the multivariate regression model. The nonexercise group had significantly greater odds of endorsing low outcome expectation (ie, the participants did not expect to derive benefit from exercise) (odds ratio [OR]=3.93, 95% confidence interval [CI]=2.08-7.42), lack of time (OR=3.36, 95% CI=1.55-7.29), and fear of falling (OR=2.35, 95% CI=1.17-4.71) than the exercise group.

LIMITATIONS

The cross-sectional nature of this study limited the ability to make causal inferences.

CONCLUSIONS

Low outcome expectation from exercise, lack of time to exercise, and fear of falling appear to be important perceived barriers to engaging in exercise in people who have PD, are ambulatory, and dwell in the community. These may be important issues for physical therapists to target in people who have PD and do not exercise regularly. The efficacy of intervention strategies to facilitate exercise adherence in people with PD requires further investigation.

The epidemiology and clinical manifestations of dysexecutive syndrome in Parkinson's disease

This mini-review summarizes the evidence of the cognitive and behavioral features of dysexecutive syndrome in Parkinson’s disease (PD). Deficits in response inhibition, set-shifting, mental flexibility, and strategy have been frequently described from the earliest stages of PD, although there are inconsistencies in study findings due to the complexity of the executive function (EF) construct and methodological limitations. Behavioral disorders of PD, e.g., apathy, distractibility, perseverative behavior, and impulse-control disorders, may be viewed as the other side of dysexecutive syndrome. Despite the interrelationship between the cognitive and behavioral domains, some reports reveal that the two syndromes may be dissociated, suggesting that both aspects must be clinically assessed. EFs are widely associated with the prefrontal areas, although dysexecutive syndrome may be observed in patients with damage to other brain regions. EFs drive numerous abilities essential to daily life, such as prospective remembering and language comprehension, which may be impaired in PD subjects. Considering the impact of dysexecutive syndrome on independence and quality of life, early detection of executive impairment is crucial in the management of PD.

Executive dysfunction in chronic cocaine users: an exploratory study

INTRODUCTION

Chronic cocaine use is associated with some executive deficits. We assessed executive functions using ecologically valid tests in chronic cocaine users.

OBJECTIVES

To investigate the relationship between executive deficits and three measures of severity of cocaine use: years of use, quantity used, and frequency of use.

METHODS

Twenty-four cocaine users were compared with twenty-seven community controls. We used Student's t-test and Chi-squared to compare means and categorical variables, respectively. Linear regression analyses for the adjusted comparative analysis between cases and controls, and severity of cocaine use among cocaine users were performed.

RESULTS

Chronic cocaine users performed worse on measures of attention and working memory (Forward and Backward Digit Span, p<.001), set-shifting abilities (difference score between the Trail Making B and A, TMB-A, p=.006), cognitive test of mental flexibility and response inhibition (Rule Shift Cards) (p<.001), and prefrontal functioning (Wisconsin Card Sorting Test, WCST, p=.023) than controls. Years of cocaine use were associated with deficits in the Backward Digit Span (p=.041; CI 95%: -.760 to -.002), the TMB-A (p=.026; CI 95%: .687 to 9.761), the Zoo Map (p=.034; CI 95%: -.480 to -.021), and the Rule Shift Cards (p=.006; CI 95%: -.836 to -.164), among others. Quantity of cocaine use was associated with executive deficits measured by the Forward Digit Span (p=.007; CI 95%: -.727 to -.133), the TMB-A (p=.021; CI 95%: 5.304-57.945), and the number of perseverative errors in the WSCT (p=.002; CI 95%: -10.654 to -2.800). Frequency of cocaine was associated with deficits in the Backward Digit Span (p=.042; CI 95%: -1.548 to -.030).

CONCLUSIONS

Chronic use of cocaine is associated with executive deficits, which may influence patients' functionality, prognosis, and therapeutic failure.

Diagnostic utility of the Key Search Test as a measure of executive functions

BACKGROUND

Executive function deficits are commonly observed in many clinical populations, highlighting the importance of appropriate diagnostic tools to screen for these deficits. Most neuropsychological tests of executive function, however, are time-consuming and difficult to administer in the case of moderate to severe cognitive decline. The aim of the present study was to examine whether the Key Search Test, a short and easy to administer test, is a useful indicator of executive function deficits in a study sample with a diagnosis of cognitive impairment.

METHODS

Participants consisted of elderly people visiting the memory clinic at the department of geriatrics of a university medical center (n= 140) and of elderly controls (n= 37). Next to the Key Search Test, other executive function tests and a memory test were administered.

RESULTS

Low to moderate correlations were found between the Key Search Test and other executive function tests. Furthermore, although the Key Search Test discriminated significantly between intact and impaired executive function (AUC = 0.677, P < 0.001), sensitivity and specificity were low and no optimal cut-off point could be determined.

CONCLUSION

The Key Search test might not be an appropriate measure of executive functions in cognitively impaired individuals.

Impairments on "open-ended" executive function tests in autism

The executive function (EF) theory of autism has received much support recently from a growing number of studies. However, executive impairments have not always been easy to identify consistently and so novel "ecologically valid" tests have been designed which tap into real-life scenarios that are relevant to and representative of everyday behavior. One characteristic of many of these tasks is that they present the participant with an "ill-structured" or "open-ended" situation. Here, we investigated the possibility that tasks with greater degrees of open-endedness might prove more sensitive to detecting executive impairment in autism. Forty-five children with autism spectrum disorder (ASD) were compared to 27 age- and IQ-matched control children on a range of cognitive tests of EF. Group differences were found on half of the tasks, with the greatest degree of impairment detected on the more open-ended tasks. The ASD group also performed more poorly on a simple control condition of a task. Detailed consideration of task performance suggested that the ASD group tended to create fewer spontaneous strategies and exhibit more idiosyncratic behavior, which particularly disadvantaged them on the more open-ended tasks. These kinds of behaviors have been reported in studies of neurological patients with frontal lobe involvement, prima facie suggesting a link between the scientific fields. However, we suggest that this behavior might equally result from a poor understanding of the implicit demands made by the experimenter in open-ended test situations, due to the socio-communicative difficulties of these children.

Strategy instruction in Parkinson's disease: influence on cognitive performance

OBJECTIVES

Though strategic deficits are extensively investigated in Parkinson's disease (PD), little is known about the effects of instruction for PD patients. Thus, we compared the ability to internally generate a cognitive strategy with the ability to use a strategy after elaborate strategy instruction.

METHODS

Patients with PD (n=14) and matched healthy controls (n=22) were administered a Numerosity Judgement task in which they had to determine different numerosities of blocks presented in a square grid. In more complex task configurations, healthy participants tend to use a subtraction strategy. Participants in our study were confronted with a counting condition (A), a strategy initiation condition without instruction (B), and a strategy elaboration and strategy training condition (C).

RESULTS

Patients and controls were comparable with respect to basic cognitive measures. PD patients and controls performed equivalently within the counting condition (A), but patients needed significantly more trials to initiate the subtraction strategy. With the exception of 1 PD patient, all patients were able to internally initiate the strategy (condition B). In condition C, both groups increased reaction times, but patients were significantly slower than controls. Moreover, only patients significantly increased error rates after strategy instruction.

CONCLUSION

As long as sufficient time is provided for solving the task, results do not show a general deficit in the ability to internally generate a cognitive strategy in PD. Failures in strategy utilization strongly depend on cognitive load (working memory, executive functions). This bears important implications for the neuropsychological rehabilitation of PD patients.