Apraxia Test Research Articles

Body representation in people with apraxia post Stroke– an observational study

ABSTRACT Objective: To investigate how two types of body representation (body schema and body image) were affected in people with and without apraxia following a supratentorial stroke. Design: Observational cross-sectional study Setting: Level 1 Specialist Neurological Rehabilitation Unit Participants: 30 participants post-stroke diagnosed with (n = 10) and without apraxia (n = 20) according to a modified version of the short Ideomotor Apraxia Test. Interventions: Not applicable Main Outcome Measures: Body schema assessed using the hand laterality recognition test and body part knowledge test; Implicit body image assessed using the sidedness test. Results: Left-sided lesions were more common in the apraxic group. Compared to people without apraxia post-stroke, those with apraxia showed significantly reduced accuracy and longer reaction times on the hand laterality test and fewer correct responses on the body part knowledge test. There was no between-groups difference in the sidedness test. Conclusions: People with apraxia showed deficits in online body representations (body schema) that are used to plan and execute actions. Future research studies could target body schema deficits as an adjunct in the rehabilitation of apraxia.

Effectiveness of a Functional Rehabilitation Program for Upper Limb Apraxia in Poststroke Patients: A Randomized Controlled Trial

ObjectiveTo analyze the effectiveness of a home-based restorative and compensatory upper limb apraxia (ULA) rehabilitation program. DesignRandomized controlled trial. SettingNeurology Unit of San Cecilio Hospital and 2 private and specialized health care centers. ParticipantsCommunity dwelling participants (N=38) between the ages of 25 and 95 years old (sex ratio, 1:1) with unilateral mild-to-moderate poststroke lesions (time of evolution since stroke, 12.03±8.98mo) and secondary ULA. InterventionsParticipants were randomly assigned to an 8-week combined ULA functional rehabilitation group (n=19) 3 days per week for 30 minutes or to a traditional health care education protocol group (n=19) once a month for 8 weeks. Both interventions were conducted at home. Main Outcome MeasuresSociodemographic and clinical data, Barthel Index (primary outcome), Lawton and Brody Scale, observation and scoring activities of daily living, the De Renzi tests for ideational and ideomotor apraxia and imitating gestures test, recognition of gestures, test for upper limb apraxia , and stroke-specific quality of life scale were assessed at 3 time points: baseline, posttreatment (8wk), and follow-up (8wk). ResultsThere were statistically significant differences among the groups regarding ideomotor apraxia, imitating gestures, global recognition of gestures, intransitive gestures, and comprehension of gesture production (P<.05) in favor of the experimental group. However, no statistically significant differences were found between the groups regarding functionality or quality of life (P>.05). Regarding the within-group effect, statistically significant differences were found in all neuropsychological outcomes at posttreatment and follow-up (P<.05). ConclusionA functional rehabilitation program was found to be superior to a traditional health care education program and resulted in improvements in neuropsychological functioning in ULA poststroke. Conventional education showed an insufficient effect on apraxia recovery. Further studies with larger sample sizes are needed to determine the effect of rehabilitation strategies on functionality and quality of life of poststroke ULA patients.

Neurocognitive assessment and DNA sequencing expand the phenotype and genotype spectrum of Alström syndrome.

Alström syndrome (OMIM#203800) is an ultra-rare autosomal recessive monogenic disease presenting pathogenic variants in ALMS1 (chromosome 2p13). It is characterized by early onset of blindness, hearing loss and systemic comorbidities, with delayed development without cognitive impairment. We aimed to investigate the cognitive functions and describe new pathogenic variants in Alström syndrome patients. Nineteen patients (13 adults, 6 children) underwent a thorough clinical, genetic, laboratory, instrumental, and neurocognitive assessment. Six new pathogenic variants in ALMS1 including the first described in exon 6 were identified. Four patients displayed a "mild phenotype" characterized by slow disease onset or absence of complications, including childhood obesity and association with at least one pathogenic variant in exon 5 or 6. At neurocognitive testing, a significant proportion of patients had deficits in three neurocognitive domains: similarities, phonological memory, and apraxia. In particular, 53% of patients showed difficulties in the auditory working memory test. We found ideomotor and buccofacial apraxia in 74% of patients. "Mild phenotype" patients performed better on auditory working memory and ideomotor apraxia test than "typical phenotype" ones (91.9 + 16.3% vs. 41.7 + 34.5% of correct answers, Z = 64.5, p < .01 and 92.5 + 9.6 vs. 61.7 + 26.3, Z = 61, p < .05, respectively). Deficits in auditory working memory, ideomotor, and buccofacial apraxia were found in these patients and fewer neuropsychological deficits were found in the "mild" phenotype group. Furthermore, in the "mild" phenotype group, it was found that all pathogenic variants are localized before exon 8.

Structural organization of the praxis network predicts gesture production: Evidence from healthy subjects and patients with schizophrenia

Hand gestures are an integral part of social interactions and communication. Several imaging studies in healthy subjects and lesion studies in patients with apraxia suggest the praxis network for gesture production, involving mainly left inferior frontal, posterior parietal and temporal regions. However, little is known about the structural connectivity underlying gesture production. We recruited 41 healthy participants and 39 patients with schizophrenia. All participants performed a gesture production test, the Test of Upper Limb Apraxia, and underwent diffusion tensor imaging. We hypothesized that gesture production is associated with structural network connectivity as well as with tract integrity. We defined the praxis network as an undirected graph comprised of 13 bilateral regions of interest and derived measures of local and global structural connectivity and tract integrity from Finsler geometry. We found an association of gesture deficit with reduced global and local efficiency of the praxis network. Furthermore, reduced tract integrity, for example in the superior longitudinal fascicle, arcuate fascicle or corpus callosum were related to gesture deficits. Our findings contribute to the understanding of structural correlates of gesture production as they first present diffusion tensor imaging data in a combined sample of healthy subjects and a patient cohort with gestural deficits.

M224. LONGITUDINAL DETERIORATION OF GESTURE PERFORMANCE IN SCHIZOPHRENIA IS UNRELATED TO SYMPTOM TRAJECTORIES

BackgroundGesture deficits in patients with schizophrenia are highly pronounced, and often linked to poor social functioning, motor abnormalities, and frontal lobe dysfunction. Although gesture performance has been associated to both negative and positive symptoms, its relationship to the severity of these symptoms is still unclear. Here, we examine how gesture performance varies as symptoms change. Furthermore, we aimed to compare gesture performance at two time points to healthy controls and first-degree relatives of schizophrenia patients. Gesture performance in relatives may indicate whether the deficits are associated with genetic liability to schizophrenia. We hypothesize that gesture performance in controls and relatives would be stable; while we expect improvement in patients when symptom severity declines.MethodsThe present study included 36 patients with schizophrenia (DSM-5 criteria; mean age 35.5 years), 28 unaffected first-degree relatives of schizophrenia patients (mean age 49.9 years) and 38 healthy controls (mean age 39.9 years). All three groups performed the Test for Upper-Limp Apraxia (TULIA), which includes pantomime (performance on verbal command) and imitative (performance upon demonstration) gestures, at two different time points, baseline and re-test (between 1–4 weeks). TULIA performance is recorded on videos and rated blind to diagnosis and stage. In addition, 22 of the 36 patients performed the TULIA at a follow-up session 6-months after baseline. Symptom severity was assessed with the Positive And Negative Syndrome Scale (PANSS). Analysis between the three groups and within patients across the different time points was done using repeated measures ANOVA in R.ResultsSymptom severity in patients declined between baseline and week 4 (T = 6.7, p<0.001, PANSS total). A 3x2x2 repeated measures ANOVA revealed significant main effects of Group, Type of Gestures, as well as, a significant interaction between Group and Time Point (all F > 3.8; p<0.5) Post hoc analysis, bonferroni corrected, revealed that patients underperformed in both pantomime and imitative gestures compared to healthy controls (p<0.0001) and relatives of schizophrenia patients, although this effect did not reach significance (p=0.26). Performance of pantomime gestures was poorer compared to imitative gestures. Interestingly, this pattern was also observed during the re-test time point (p<0.0001), though gesture performance for imitative gestures significantly declined compared to baseline in patients (p<0.05). In contrast, healthy controls performed better than both patients (p<0.0001) and relatives (p-0.09) and remained stable during the re-test. Likewise, relatives performed intermediate between patients and healthy controls at both time points with scores reaching significance only at re-test (p<0.001). At baseline, imitation was better than pantomime in relatives, but with re-test imitation scores declined while pantomime scores remained stable. Finally, at the 6-month follow-up patients still exhibited lower gesture performance compared to baseline (F=22.25; p<0.05).DiscussionGesture performance in schizophrenia patients remained significantly impaired across time-points, suggesting an extended effect on poor social functioning despite symptom change. In addition, schizophrenia patients and their relatives showed a significant impairment when performing imitative gestures during the re-test compared to baseline. These results call for interventions specifically targeting gesture and social cognition, which would greatly improve patients’ quality of life. Finally, our findings suggest a trait component to gesture behavior that might be linked to genetic liability to psychosis.

Interhemispheric facilitation of gesturing: A combined theta burst stimulation and diffusion tensor imaging study

BackgroundImaging studies point to a posture (finger vs. hand) and domain-specific neural basis of gestures. Furthermore, modulation of gestures by theta burst stimulation (TBS) may depend on interhemispheric disinhibition. Objective/HypothesisIn this randomized sham-controlled study, we hypothesized that dual site continuous TBS over left inferior frontal gyrus (IFG-L) and right inferior parietal gyrus (IPL-R) predominantly affects pantomime of finger postures. Furthermore, we predicted that dual cTBS improves imitation of hand gestures if the effect correlates with measures of callosal connectivity. MethodsForty-six healthy subjects participated in this study and were targeted with one train of TBS in different experimental sessions: baseline, sham, single site IFG-L, dual IFG-L/IPL-R, single site IPL-R. Gestures were evaluated by blinded raters using the Test for Upper Limb Apraxia (TULIA) and Postural Imitation Test (PIT). Callosal connectivity was analyzed by diffusion tensor imaging (DTI). ResultsDual cTBS significantly improved TULIAtotal (F [3, 28] = 4.118, p = .009), but did not affect TULIApantomime. The beneficial effect was driven by the cTBS over IPL-R, which improved TULIAimitation (p = .038). Furthermore, TULIAimitation significantly correlated with the microstructure (fractional anisotropy) of the splenium (r = 0.420, p = .026), corrected for age and whole brain volume. ConclusionsThe study suggests that inhibition of IPL-R largely accounted for improved gesturing, possibly through transcallosal facilitation of IPL-L. Therefore, the findings may be relevant for the treatment of apraxic stroke patients. Gesture pantomime and postural gestures escaped the modulation by dual cTBS, suggesting a more widespread and/or variable neural representation.

Reliability and Validity of the Comprehensive Limb and Oral Apraxia Test: Standardization and Clinical Application in Korean Patients With Stroke.

Objective To develop and standardize the Limb and Oral Apraxia Test (LOAT) for Korean patients and investigate its reliability, validity, and clinical usefulness for patients with stroke.MethodsWe developed the LOAT according to a cognitive neuropsychological model of limb and oral praxis. The test included meaningless, intransitive, transitive, and oral praxis composed of 72 items (56 items on limb praxis and 16 items on oral praxis; maximum score 216). We standardized the LOAT in a nationwide sample of 324 healthy adults. Intra-rater and inter-rater reliability and concurrent validity tests were performed in patients with stroke. We prospectively applied the LOAT in 80 patients and analyzed the incidence of apraxia. We also compared the clinical characteristics between the apraxia and non-apraxia groups.ResultsThe internal consistency was high (Cronbach’s alpha=0.952). The inter-rater and intra-rater reliability and concurrent validity were also high (r=0.924–0.992, 0.961–0.999, and 0.830, respectively; p<0.001). The mean total, limb, and oral scores were not significantly different according to age and education (p>0.05). Among the 80 patients with stroke, 19 (23.8%) had limb apraxia and 21 (26.3%) had oral apraxia. Left hemispheric lesions and aphasia were significantly more frequently observed in the limb/oral apraxia group than in the non-apraxia group (p<0.001).ConclusionThe LOAT is a newly developed comprehensive test for limb and oral apraxia for Korean patients with stroke. It has high internal consistency, reliability, and validity and is a useful apraxia test for patients with stroke.

Single Session Transcranial Magnetic Stimulation Ameliorates Hand Gesture Deficits in Schizophrenia.

Social interaction is impaired in schizophrenia, including the use of hand gestures, which is linked to poor social perception and outcome. Brain imaging suggests reduced neural activity in a left-lateralized frontoparietal network during gesture preparation; therefore, gesturing might be improved through facilitation of left hemispheric brain areas or via disruption of interhemispheric inhibition from the right homolog. This study tested whether repetitive transcranial magnetic stimulation (rTMS) protocols would improve gesture performance in schizophrenia. This randomized, placebo-controlled, double-blind, crossover trial applied 3 different protocols of rTMS separated by 48 h. Twenty right-handed schizophrenia patients and 20 matched healthy controls received facilitatory intermittent theta burst stimulation (iTBS) over the left inferior frontal gyrus (IFG), inhibitory continuous theta burst stimulation (cTBS) over right inferior parietal lobe (IPL), and placebo over left IPL in randomized order. Primary outcome was change in the test of upper limb apraxia (TULIA), rated from video recordings of hand gesture performance. Secondary outcome was change in manual dexterity using the coin rotation task. Participants improved on both tasks following rTMS compared with baseline. Only patients improved gesture performance following right IPL cTBS compared with placebo (P = .013). The results of the coin rotation parallel those of the TULIA, with improvements following right IPL cTBS in patients (P = .001). Single sessions of cTBS on the right IPL substantially improved both gesture performance accuracy and manual dexterity. The findings point toward an inhibition of interhemispheric rivalry as a potential mechanism of action.

Development and Clinical Application of New Comprehensive Limb and Oral Apraxia Test in Stroke Patients

Apraxia is a common cognitive motor deficit that can occur after a stroke but there is no standardized apraxia test for Korean stroke patients. We developed and standardized the Limb and Oral Apraxia Test (LOAT) for Korean patients and investigated its reliability, validity, and clinical usefulness for stroke patients.

Clinical, neuropsychological and imaging characteristics of Alzheimer's disease patients presenting as corticobasal syndrome

BackgroundCorticobasal syndrome (CBS) can harbor diverse pathologies, such as corticobasal degeneration (CBD) and Alzheimer's disease (AD). CSF biochemical analysis in CBS patients can confidently distinguish between an AD (CBS-AD) and a non-AD (CBS-nAD) pathology. ObjectiveWe utilized classical CSF biomarkers to make a distinction between the two groups and examine their clinical, neuropsychological, neuropsychiatric and imaging differences. MethodsSeventeen patients with a CBS phenotype were included. Detailed clinical history, and neurological examination data were recorded. A thorough neuropsychological and neuropsychiatric test battery was performed, including Goldenberg apraxia test. Simple linear MRI measurements and planimetry data were utilized. CSF biomarkers for AD were ascertained. ResultsFive of seventeen CBS patients had a CSF AD profile. Patients with a CSF AD profile (CBS-AD; n = 5) were older and had a greater age at disease onset compared to CBS-nAD. CBS-AD patients had more frequently alien hand phenomena at examination and greater hippocampi surface asymmetry at MRI. CBS-nAD patients (n = 12) had lower superior colliculi width values. ConclusionClinical, neuropsychological and imaging data cannot confidently differentiate CBS-AD from CBS-nAD patients.

Apraxia screening predicts Alzheimer pathology in frontotemporal dementia

ObjectivesFrontotemporal dementia (FTD) is a heterogeneous clinical syndrome linked to diverse types of underlying neuropathology. Diagnosis is mainly based on clinical presentation and accurate prediction of underlying neuropathology remains difficult.MethodsWe...

An Explorative Note on Apraxia Tests.

Apraxia is stated independent of primary motor disorders. However, patient groups suffering from stroke or dementia can reveal motor impairments. In this study we examined the dependence of apraxia tests of imitation and pantomime on a latent motor component using a principal component analysis. With samples sizes of 11 patients suffering from dementia of the Alzheimer's type and 15 healthy control subjects, clear limitations concerning the validity of the results are given. Nevertheless, we could observe strong dependence of the three apraxia tests, especially the imitation of finger and hand gestures, on a latent motor component in this preliminary examination. We suggest confirmation by larger samples sizes and to control for the basic motor capacity when testing for signs of apraxia in such patient samples.

Deficient supplementary motor area at rest: Neural basis of limb kinetic deficits in Parkinson's disease.

Parkinson's disease (PD) patients frequently suffer from limb kinetic apraxia (LKA) affecting quality of life. LKA denotes an impairment of precise and independent finger movements beyond bradykinesia, which is reliably assessed by coin rotation (CR) task. BOLD fMRI detected activation of a left inferior parietal-premotor praxis network in PD during CR. Here, we explored which network site is most critical for LKA using arterial spin labeling (ASL). Based on a hierarchical model, we hypothesized that LKA would predominantly affect the functional integrity of premotor areas including supplementary motor areas (SMA). Furthermore, we suspected that for praxis function with higher demand on temporal-spatial processing such as gesturing, inferior parietal lobule (IPL) upstream to premotor areas would be essential. A total of 21 PD patients and 20 healthy controls underwent ASL acquisition during rest. Behavioral assessment outside the scanner involved the CR, finger tapping task, and the test of upper limb apraxia (TULIA). Whole-brain analysis of activity at rest showed a significant reduction of CR-related perfusion in the left SMA of PD. Furthermore, the positive correlation between SMA perfusion and CR, seen in controls, was lost in patients. By contrast, TULIA was significantly associated with the perfusion of left IPL in both patients and controls. In conclusion, the findings suggest that LKA in PD are linked to an intrinsic disruption of the left SMA function, which may only be overcome by compensatory network activation. In addition, gestural performance relies on IPL which remains available for functional recruitment in early PD.

T177. STRUCTURAL ORGANIZATION OF THE PRAXIS NETWORK PREDICTS GESTURE PRODUCTION: EVIDENCE FROM HEALTHY SUBJECTS AND PATIENTS WITH SCHIZOPHRENIA

BackgroundHand gestures are an integral part of social interactions and are involved in nonverbal and verbal communication. The convey language that is expressed by motor actions, and thus depend on the interplay of various brain regions. Several functional magnetic resonance imaging studies in healthy subjects suggest the praxis network for gesture production, involving distinct frontal, parietal and temporal regions. Lesions studies in subjects with apraxia, following left brain damage corroborate these findings. However, little is known about the structural connectivity underlying gesture production. We aimed to provide novel insights into the structural connectivity of the praxis network and how it is related to gesture production.MethodsOur sample consisted of 41 healthy subjects and of 40 patients with schizophrenia, demonstrating gesture impairments and structural network abnormalities. All participants performed a gesture production test, the test of upper limb apraxia and underwent diffusion weighted magnetic resonance imaging. Finsler geometry was used to investigate structural connectivity and graph theory to estimate global and local efficiency of the praxis network, which consists of 13 bilateral regions of interest.ResultsOur findings showed an association of gesture production with network attributes and specific connections within the praxis network. Thus, global and local efficiency and most of the intra- and interhemispheric connections within the gesture network predicted gesture production across groups. Global efficiency of the praxis network further predicted gesture production only in the patient group. Local efficiency of many ROIs and connections of interest predicted production in patients at trend-level. In contrast, there were no significant or trend-level associations of gesture production with network attributes in controls.DiscussionThe results revealed an association of impaired gesture performance with structural alterations of the praxis network, including global and local efficiency and many connections of interest. Our findings are of great importance in the understanding of the structural correlates of gesture production and shed further light on the neural underpinnings of gesture deficits in a patient group with severe social deficits.

Apraxia profiles—A single cognitive marker to discriminate all variants of frontotemporal lobar degeneration and Alzheimer's disease

IntroductionApraxia is common in neurodegenerative dementias but underrepresented in clinical workup for differential diagnoses. MethodsPraxis-profiles were assessed with the Dementia Apraxia Test in 93 patients with early stages of biologically supported Alzheimer's disease or frontotemporal lobar degeneration: semantic primary-progressive aphasia, nonfluent primary-progressive aphasia, and behavioral variant frontotemporal dementia. Associations with core cognitive deficits of the dementia subtypes (i.e., visuospatial, sociocognitive, and semantic-linguistic) were explored. ResultsPatients showed significant apraxia compared with healthy controls but also disease-specific praxis-profiles. Using only the Dementia Apraxia Test, all four dementia subtypes could be correctly discriminated in 64.4% of cases, and in 78.2% when only distinguishing Alzheimer's disease versus frontotemporal lobar degeneration. Praxis-profiles showed consistent associations with core cognitive impairments of the different dementia subtypes. DiscussionThe Dementia Apraxia Test is a valid, time-efficient and versatile cognitive marker to delineate variants of frontotemporal lobar degeneration and Alzheimer's disease in clinical routine, facilitating differential diagnoses of dementia subtypes in early disease stages.

Conscious attention defect and inhibitory control deficit in Parkinson's Disease-Mild Cognitive Impairment: A comparison study with Amnestic Mild Cognitive Impairment multiple domain.

Frontal/executive dysfunction commonly occurs in Parkinso's disease - Mild Cognitive Impairment (PD-MCI patients). However, to date, the number of studies comparing PD-MCI and MCI patients of other etiologies are too small. The present study aims at clarifying the attention/working memory and executive dysfunction of PD-MCI patients in comparison to amnestic MCI multiple domain patients with first extended then abbreviated structural brain changes suggesting preclinical Alzheimer's Disease. 40 PD-MCI patients and 40 amnestic MCI multiple domain (aMCI+) patients were diagnosed according to the International guidelines. 22 healthy subjects were also recruited as control group. The groups were assessed by a wide neuropsychological battery, including measures of attention/working memory (Digit Span and Stroop Test), executive functions (Tower of London-Drexel Version -TOLDX- and Brixton Test), language (Boston Naming Test and Category Fluency), memory (Prose Recall and Pairs Associates Learning), and visuospatial function (Street's Completion Test and Constructive Apraxia Test). Performances were compared by non parametric tests. Spearman correlations were performed to explore association between neuropsychological measures of attention/working memory and executive functions in PD-MCI group. The PD-MCI patients performed worse on Digit Span and Stroop Interference/Error than aMCI+ and controls. AMCI+ patients, in turn, showed a greater deficit on TOLDX Initiation Time and on Violation Time than PD-MCI and controls. Both PD-MCI and aMCI+ patients reported lower scores on Stroop Interference/Time than controls. Moreover, aMCI+ patients performed worse then controls on Brixton Test. Positive correlations between Digit Span and Stroop Interference/Error, Stroop Interference/Error and TOLDX Execution Time, Total Time and Violation Time, Stroop Interference Time and TOLDX Move Score and Total Time were found in PD-MCI group. PD-MCI patients mainly present a conscious attention defect and an inhibitory control deficit than aMCI+. PD-MCI patients with deficits in attention/working memory domain should undergo specific cognitive trainings in order to improve cognitive abilities and prevent Parkinson's Disease Dementia onset.

Gesture impairments in schizophrenia are linked to increased movement and prolonged motor planning and execution

Schizophrenia patients present with a variety of impaired nonverbal communication skills. Performance of hand gestures is frequently impaired and associated with ratings of motor abnormalities. However, the impact of motor abnormalities to gesture performance remains unclear. To test the association between quantitative measures of motor behavior and qualitative ratings of gesture performance, we quantified movement parameters semi-automatically in videotaped recordings of gesture assessment. Thirty-one patients with schizophrenia (77.4%), schizophreniform (19.4%) or schizoaffective disorder (3.2%) and 32 healthy controls matched for age, gender and education underwent clinical assessment. Performance of the test of upper limb apraxia (TULIA) was video-taped in all subjects. The videos were analyzed with motion energy analysis software (MEA) to determine motion and time parameters.Patients and controls differed significantly in quantitative gesture performance: patients required more movement and more time to complete the tasks. Differences increased in patients with qualitatively impaired gesture production ratings (p<0.01). Group differences were most pronounced in the pantomime domain, when gestures are performed following verbal instruction. In patients, ratings of motor abnormalities correlated with duration of movement, while behavioral disorganization correlated with the amount of movements during gesture performance.Disorder related motor symptoms, aberrant action observation, planning and monitoring as well as internal clock abnormalities may explain the poor performance of hand gestures in schizophrenia. Quantitative video analysis offers a unique possibility to analyze movement patterns as a direct functional output of the motor system. In the future, it may assist monitoring, staging and prognosis in schizophrenia.

Nature and Specificity of Gestural Disorder in Children with Developmental Coordination Disorder: A Multiple Case Study.

Aim: Praxis assessment in children with developmental coordination disorder (DCD) is usually based on tests of adult apraxia, by comparing across types of gestures and input modalities. However, the cognitive models of adult praxis processing are rarely used in a comprehensive and critical interpretation. These models generally involve two systems: a conceptual system and a production system. Heterogeneity of deficits is consistently reported in DCD, involving other cognitive skills such as executive or visual-perceptual and visuospatial functions. Surprisingly, few researches examined the impact of these functions in gestural production. Our study aimed at discussing the nature and specificity of the gestural deficit in DCD using a multiple case study approach.Method: Tasks were selected and adapted from protocols proposed in adult apraxia, in order to enable a comprehensive assessment of gestures. This included conceptual tasks (knowledge about tool functions and actions; recognition of gestures), representational (transitive, intransitive), and non-representational gestures (imitation of meaningless postures). We realized an additional assessment of constructional abilities and other cognitive domains (executive functions, visual-perceptual and visuospatial functions). Data from 27 patients diagnosed with DCD were collected. Neuropsychological profiles were classified using an inferential clinical analysis based on the modified t-test, by comparison with 100 typically developing children divided into five age groups (from 7 to 13 years old).Results: Among the 27 DCD patients, we first classified profiles that are characterized by impairment in tasks assessing perceptual visual or visuospatial skills (n = 8). Patients with a weakness in executive functions (n = 6) were then identified, followed by those with an impaired performance in conceptual knowledge tasks (n = 4). Among the nine remaining patients, six could be classified as having a visual spatial/visual constructional dyspraxia. Gestural production deficits were variable between and within profiles.Discussion: This study confirmed the heterogeneity of gestural production deficit among children with a diagnosis of DCD, at both intra- and inter-individual levels. The contribution of other cognitive deficits in most of the profiles allows discussing the specificity of gestural difficulties. This argues in favor of the necessity to distinguish gestural problems with other deficits made apparent through gesture.

The test of time: a history of clock drawing.

The clock drawing test (CDT) has become one of the most widely used cognitive screening instruments in clinical and research settings. Its effectiveness, acceptability, and quick and easy administration have made it a staple for cognitive screening in dementia and a wide range of brain disorders. Despite a spike in popularity since the 1990s, its origins are relatively unknown. The goal of this review is to chronicle its saga and chart its usage over time. PsycInfo, Medline, and PubMed literature searches were performed from earliest record to June 2016, in addition to manual cross-referencing of bibliographies, with a focus before 1990. Summary of relevant articles and books up until 1989 is included, as well as clinical applications and surveys that track CDT usage over time. While MacDonald Critchley's well-known textbook from 1953, The Parietal Lobes, is often cited as the first mention of the CDT, its recorded use actually stretches back more than a century to 1915. A review of the literature shows that the CDT began as a test for aphasia-related disorders and constructional apraxia until its entry into contemporary cognitive screening in the 1980s when it primarily became a cognitive screen. Its usage took off in 1989 with over 2000 publications since. Despite a fairly obscure existence for decades, the CDT has emerged as an effective and ideal cognitive screening instrument for a wide range of conditions. Its use continues to increase, and it has been incorporated into several widely used cognitive screening batteries. Copyright © 2017 John Wiley & Sons, Ltd.

Bimanual Gesture Imitation in Alzheimer's Disease.

Unimanual gesture production or imitation has often been studied in Alzheimer's disease (AD) during apraxia testing. In the present study, it was hypothesized that bimanual motor tasks may be a sensitive method to detect impairments of motor cognition in AD due to increased demands on the cognitive system. We investigated bimanual, meaningless gesture imitation in 45 AD outpatients, 38 subjects with mild cognitive impairment (MCI), and 50 normal controls (NC) attending a memory clinic. Participants performed neuropsychological background testing and three tasks: the Interlocking Finger Test (ILF), Imitation of Alternating Hand Movements (AHM), and Bimanual Rhythm Tapping (BRT). The tasks were short and easy to administer. Inter-rater reliability was high across all three tests. AD patients performed significantly poorer than NC and MCI participants; a deficit to imitate bimanual gestures was rarely found in MCI and NC participants. Sensitivity to detect AD ranged from 0.5 and 0.7, specificity beyond 0.9. ROC analyses revealed good diagnostic accuracy (0.77 to 0.92). Impairment to imitate bimanual gestures was mainly predicted by diagnosis and disease severity. Our findings suggest that an impairment to imitate bimanual, meaningless gestures is a valid disease marker of mild to moderate AD and can easily be assessed in memory clinic settings. Based on our preliminary findings, it appears to be a separate impairment which can be distinguished from other cognitive deficits.