Assessing limb apraxia after ischemic stroke: validation of the Chinese version of the diagnostic instrument for limb apraxia-short version (DILA-S) classic subtests

OBJECTIVE

This study aimed to translate and validate the Chinese version of the Diagnostic Instrument for Limb Apraxia-Short Version (DILA-S) classic subtests in Chinese patients after ischemic stroke.

METHODS

The DILA-S was translated and adapted for use in Mandarin-speaking Chinese patients. Internal consistency, test-retest reliability, dimensionality, convergent validity, divergent validity, and concurrent validity were tested.

RESULTS

A total of 112 ischemic stroke patients were included. The internal consistency (Cronbach's alpha 0.85 ~ 0.92) and test-retest reliability (ICC 0.88 ~ 0.93) were found satisfactory. Exploratory factor analysis obtained two factors for the imitation subtests and the execution scale of the pantomime of tool use. Convergent validity was supported by strong correlations (ρ > 0.7) between the scores of the DILA-S subtests and the LOTCA motor praxis subscale. Divergent validity was acceptable for weak to moderate correlations (ρ ranged from -0.25~ -0.41) between the scores of the DILA-S subtests and the NIHSS. Concurrent validity was supported by strong correlations (ρ > 0.7) between the scores of the DILA-S subtests and the MoCA, as well as strong correlations (ρ > 0.6 < 0.7) between the scores of the DILA-S subtests and the BI.

CONCLUSION

The Chinese version of the DILA-S classic subtests demonstrated satisfactory psychometric properties for assessing limb apraxia in Chinese patients after ischemic stroke.

100 years after Liepmann-Lesion correlates of diminished selection and application of familiar versus novel tools

100 years ago, Liepmann highlighted the role of left ventro-dorsal lesions for impairments in conceptual (rather ventral) and motor (more dorsal) related aspects of apraxia. Many studies thereafter attributed to an extended left fronto-temporo-parietal network. Yet, to date there are only few studies that looked at apraxic performance in the selection and application of familiar versus novel tools. In the current study we applied modern voxel-based lesion-symptom mapping (VLSM) to analyze neural correlates of impaired selection and application of familiar versus novel tools. 58 left (LBD) and 51 right brain damaged (RBD) stroke patients participated in the Novel Tools Test (NTT) and the Familiar Tools Test (FTT) of the Diagnostic Instrument for Limb Apraxia (DILA-S). We further assessed performance in control tasks, namely semantic knowledge (BOSU), visuo-spatial working memory (Corsi Block Tapping) and meaningless imitation of gestures (IML). Impaired tool use was most pronounced after LBD. Our VLSM results in the LBD group suggested that selection- versus application-related aspects of praxis and semantics of familiar versus novel tool use can be behaviorally and neuro-anatomically differentiated. For impairments in familiar tool tasks, the major focus of lesion maps was rather ventral while deficiencies in novel tool tasks went along with rather dorsal lesions. Affected selection processes were linked to rather anterior lesions, while impacted application processes went along with rather posterior lesion maps. In our study, particular tool selection processes were rather specific for familiar versus novel tools. Foci for lesion overlaps of experimental and control tasks were noticed ventrally for semantic knowledge and FTT, in fronto-parietal regions for working memory and NTT, and ventro-dorsally for imitation of meaningless gestures and the application of NTT and FTT. We visualized our current interpretation within a neuroanatomical model for apraxia of tool use.

Assessing Anosognosia in Apraxia of Common Tool-Use With the VATA-NAT

In neurological patients, a lack of insight into their impairments can lead to possibly dangerous situations and non-compliance in rehabilitation therapy with worse rehabilitation outcomes as a result. This so called anosognosia is a multifaceted syndrome that can occur after brain damage affecting different neurological or cognitive functions. To our knowledge no study has investigated anosognosia for apraxia of common tool-use (CTU) so far. CTU-apraxia is a disorder frequently occurring after stroke that affects the use of familiar objects. Here, we introduce a new questionnaire to diagnose anosognosia for CTU-apraxia, the Visual Analogue Test assessing Anosognosia for Naturalistic Action Tasks (VATA-NAT). This assessment is adapted from a series of VATA-questionnaires that evaluate insight into motor (VATA-M) or language (VATA-L) impairment and take known challenges such as aphasia into account. Fifty one subacute stroke patients with left (LBD) or right (RBD) brain damage were investigated including patients with and without CTU-apraxia. Patients were assessed with the VATA-L, -M and -NAT before and after applying a diagnostics session for each function. Interrater reliability, composite reliability as well as convergent and divergent validity were evaluated for the VATA-NAT. Seven percent of the LBD patients with CTU-apraxia demonstrated anosognosia. After tool-use diagnostics this number increased to 20 percent. For the VATA-NAT, psychometric data revealed high interrater-reliability (τ ≥ 0.828), composite reliability (CR ≥ 0.809) and convergent validity (τ = -0.626). When assessing patients with severe aphasia, the possible influence of language comprehension difficulties needs to be taken into account for interpretation. Overall, close monitoring of anosognosia over the course of rehabilitation is recommended. With the VATA-NAT we hereby provide a novel assessment for anosognosia in patients with CTU-apraxia. For diagnosing anosognosia we recommend to combine this new tool with the existing VATA-M and -L subtests, particularly in patients who demonstrate severe functional deficits.

Reliability and Validity of Korean Version of Apraxia Screen of TULIA (K-AST)

OBJECTIVE

To evaluate the reliability and validity of Korean version of AST (K-AST) as a bedside screening test of apraxia in patients with stroke for early and reliable detection.

METHODS

AST was translated into Korean, and the translated version received authorization from the author of AST. The performances of K-AST in 26 patients (21 males, 5 females; mean age 65.42±17.31 years) with stroke (23 ischemic, 3 hemorrhagic) were videotaped. To test the reliability and validity of K-AST, the recorded performances were assessed by two physiatrists and two occupational therapists twice at a 1-week interval. The patient performances at admission in Korean version of Mini-Mental State Examination (K-MMSE), self-care and transfer categories of Functional Independence Measure (FIM), and motor praxis area of Loewenstein Occupational Therapy Cognitive Assessment, the second edition (LOTCA-II) were also evaluated. Scores of motor praxis area of LOTCA-II was used to assess the validity of K-AST.

RESULTS

Inter-rater reliabilities were 0.983 (p<0.001) at the first assessment and 0.982 (p<0.001) at the second assessment. For intra-rater (test-retest) reliabilities, the values of four raters were 0.978 (p<0.001), 0.957 (p<0.001), 0.987 (p<0.001), and 0.977 (p<0.001). K-AST showed significant correlation (r=0.758, p<0.001) with motor praxis area of LOTCA-II test. K-AST also showed positive correlations with the total FIM score (r=0.694, p<0.001), the selfcare category of FIM (r=0.705, p<0.001) and the transfer category of FIM (r=653, p<0.001).

CONCLUSION

K-AST is a reliable and valid test for bedside screening of apraxia.