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This study examined the effect of a change in target voice on word recall during a multi-talker conversation. Two experiments were conducted using matrix sentences to assess the cost of a single endogenous switch in non-spatial attention. Performance in a yes-no recognition task was significantly worse when a target voice changed compared to when it remained the same after a turn-taking gap. We observed a decrease in target hit rate and sensitivity, and an increase in masker confusion errors following a change in voice. These results highlight the cognitive demands of not only engaging attention on a new talker, but also of disengaging attention from a previous target voice. This shows that exposure to a voice can have a biasing effect on attention that persists well after a turn-taking gap. A second experiment showed that there was no change in switching performance using different talker combinations. This demonstrates that switching costs were consistent and did not depend on the degree of acoustic differences in target voice characteristics.

To develop, in Australian English, the first mixed-gender, multi-talker matrix sentence test.Speech material consisted of a 50-word base matrix whose elements can be combined to form sentences of identical syntax but unpredictable content. Ten voices (five female and five male) were recorded for editing and preliminary level equalization. Elements were presented as single-talker sentences-in-noise during two perceptual tests: an optimization phase that provided the basis for further level correction, and an evaluation phase that perceptually validated those changes.Ten listeners participated in the optimization phase; these and an additional 32 naïve listeners completed the evaluation test. All were fluent in English and all but one had lived in Australia for2 years.Optimization reduced the standard deviation (SD) and speech reception threshold (SRT) range across all speech material (grand mean SRT = -10.6 dB signal-to-noise ratio, median = -10.8, SD =1.4, range =13.7, slope =19.3%/dB), yielding data consistent with cross-validated matrix tests in other languages. Intelligibility differences between experienced and naïve listeners were minimal.The Australian matrix corpus provides a robust set of test materials suitable for both clinical assessment and research into the dynamics of active listening in multi-talker environments.

Background. Neurological deficits after a stroke are commonly classified according to motor function for clinical decision making regarding discharge and rehabilitation. Participants in clinical stroke studies are also stratified by motor function to avoid a sampling bias. Objective. This post hoc analysis examined a suite of upper limb functional assessment tools to test the hypothesis that motor function of survivors of stroke can be stratified using 2 simple tests of manual dexterity despite the heterogeneity of the population. Methods. The functional ability of the more affected hand and arm was assessed for 67 hemiparetic patients, aged 18 to 83 years (mean ± standard deviation, 59.8 ± 14.0 years), at 1 to 264 months after a stroke (23.6 ± 39.6 months) using the Wolf Motor Function Test (WMFT), upper limb motor Fugl-Meyer Assessment (F-M), Box and Block Test (BBT), grooved pegboard test, and wrist range of motion. We tested the strength of our proposed stratification scheme with a hypothesis-driven hierarchical cluster analysis using standardized raw scores and dichotomous BBT and grooved pegboard test values. Results. The most salient discriminator between low and higher motor function was the ability to move >1 block on the BBT. Within the higher function group, the ability to place all 25 pegs on the grooved pegboard test discriminated between moderate and high motor function. The derived scheme was congruent with clinical observations. The WMFT timed tasks, F-M scores, and range of motion did not discriminate functional groups. Conclusions. Two simple unambiguous and objective tests of gross (BBT) and fine (grooved pegboard test) manual dexterity discriminated 3 groups of motor function ability for a heterogeneous group of patients after stroke.

Background. Functional ability is regularly monitored poststroke to assess improvement and the efficacy of clinical trials. The balance between implementation times and sensitivity has led to multidomain tools that aim to assess upper-limb function comprehensively. Objective. This study implemented 3 common multidomain tools to investigate their suitability across a broad spectrum of movement ability after stroke. Methods. Forty-nine hemiparetic patients (18 females), aged 22 to 83 years and 24.7 ± 39.2 months poststroke, were assessed before and after a 14-day upper-limb rehabilitation program of Wii-based Movement Therapy. Assessments included the upper-limb motor subscale of the Fugl-Meyer Assessment (F-M), the Wolf Motor Function Test (WMFT), and the Motor Assessment Scale (MAS) upper-limb sections 6 to 8. The MAS was analyzed both with and without the hierarchical system. Patients were stratified with low, moderate, or high motor-function. Results. Upper-limb function improved significantly for the pooled cohort for all assessments ( P < .001), although ceiling effects were evident for the F-M, floor effects for the WMFT, and both floor and ceiling effects for MAS. When analyzed by stratified subgroup these improvements were significant for all groups with the F-M, for the moderate and high motor-function groups with both the WMFT and the MAS scored without hierarchical system, but only for the high motor-function group with the hierarchically scored MAS. Conclusion. These results suggest that no single test is suitable for measuring function and improvement across the spectrum of poststroke upper-limb dysfunction and that assessment tool selection should be based on the level of residual motor-function of individual patients.

Sensation is commonly impaired immediately post-stroke but little is known about the long-term changes in cutaneous sensation that have the capacity to adversely impact independence and motor-function. We investigated cutaneous sensory thresholds across the hand in the chronic post-stroke period. Cutaneous sensation was assessed in 42 community-dwelling stroke patients and compared to 36 healthy subjects. Sensation was tested with calibrated monofilaments at 6 sites on the hand that covered the median, ulnar and radial innervation territories and included both glabrous (hairless) and hairy skin. The motor-function of stroke patients was assessed with the Wolf Motor Function Test and the upper-limb motor Fugl-Meyer Assessment. Impaired cutaneous sensation was defined as monofilament thresholds >3 SD above the mean of healthy subjects and good sensation was ≤ 3 SD. Cutaneous sensation was impaired for 33% of patients and was 40-84% worse on the more-affected side compared to healthy subjects depending on the site (p