Comparing a Novel Neuroanimation Experience to Conventional Therapy for High-Dose Intensive Upper-Limb Training in Subacute Stroke: The SMARTS2 Randomized Trial

BACKGROUND Evidence from animal studies suggests that greater reductions in poststroke motor impairment can be attained with significantly higher doses and intensities of therapy focused on movement quality. These studies also indicate a dose-timing interaction, with more pronounced effects if high-intensity therapy is delivered in the acute/subacute, rather than chronic, poststroke period. OBJECTIVE To compare 2 approaches of delivering high-intensity, high-dose upper-limb therapy in patients with subacute stroke: a novel exploratory neuroanimation therapy (NAT) and modified conventional occupational therapy (COT). METHODS A total of 24 patients were randomized to NAT or COT and underwent 30 sessions of 60 minutes time-on-task in addition to standard care. The primary outcome was the Fugl-Meyer Upper Extremity motor score (FM-UE). Secondary outcomes included Action Research Arm Test (ARAT), grip strength, Stroke Impact Scale hand domain, and upper-limb kinematics. Outcomes were assessed at baseline, and days 3, 90, and 180 posttraining. Both groups were compared to a matched historical cohort (HC), which received only 30 minutes of upper-limb therapy per day. RESULTS There were no significant between-group differences in FM-UE change or any of the secondary outcomes at any timepoint. Both high-dose groups showed greater recovery on the ARAT (7.3 ± 2.9 points; P = .011) but not the FM-UE (1.4 ± 2.6 points; P = .564) when compared with the HC. CONCLUSIONS Neuroanimation may offer a new, enjoyable, efficient, and scalable way to deliver high-dose and intensive upper-limb therapy

Time-dependent competition between goal-directed and habitual response preparation

Habits are commonly conceptualized as learned associations whereby a stimulus triggers an associated response. We propose that habits may be better understood as a process whereby a stimulus triggers only the preparation of a response, without necessarily triggering its initiation. Critically, this would allow a habit to exist without ever being overtly expressed, if the prepared habitual response is replaced by a goal-directed alternative before it can be initiated. Consistent with this hypothesis, we show that limiting the time available for response preparation can unmask latent habits. Participants practiced a visuomotor association for 4 days, after which the association was remapped. Participants easily learned the new association but habitually expressed the original association when forced to respond rapidly (~300–600 ms). More extensive practice reduced the latency at which habitual responses were prepared, in turn increasing the likelihood of their being expressed. The timecourse of habit expression was captured by a computational model in which habitual responses are automatically prepared at short latency but subsequently replaced by goal-directed responses. Our results illustrate robust habit formation in humans and show that practice affects habitual behaviour in two distinct ways: by promoting habit formation and by modulating the likelihood of habit expression.status: publishe

A common format for representing spatial location in visual and motor working memory

Does the mind rely on similar systems of spatial representation for both perception and action? Here, we assess the format of location representations in two simple spatial localization tasks. In one task, participants simply remembered the location of an item based solely on visual input. In another, participants remembered the location of a point in space based solely on haptic input. A careful analysis of participants’ errors revealed that, in both tasks, participants errors were more consistent with the use of polar coordinates than Cartesian coordinates. Thus, we argue that polar coordinates may be a common format for representing location information across modalities

A behavioral study on tonal working memory in musicians and non-musicians.

Tonal working memory (WM) refers to the maintenance and the online manipulation of tonal information and has been suggested to involve different mechanisms than verbal WM. Previous research has suggested that verbal WM performance is determined by the duration instead of the number of verbal materials. We investigated in the present study to what degree that the number and the duration of notes in a sequence influence the tonal WM in participants with or without professional musical training. The forward tonal discrimination task in Experiment 1 tested the maintenance of the tonal information and the backward N-back tonal task in Experiment 2 probed the running memory span of tonal information. Results show that the number of notes, but not the duration of notes in a tone sequence significantly affects tonal WM performance for both musicians and non-musicians. In addition, within a minimum musical context, musicians outperformed non-musicians in the N-back tonal task but not the forward tone sequence discrimination task. These findings indicate that the capacity of tonal WM is determined by the number of notes but not the duration of notes in a sequence to be memorized, suggesting a different mechanism underlying tonal WM from verbal WM. Furthermore, the present study demonstrated that N-back tonal task is a quantitative and sensitive measure of the effect of musical training on tonal WM

Time-dependent competition between goal-directed and habitual response preparation.

Habits are commonly conceptualized as learned associations whereby a stimulus triggers an associated response. We propose that habits may be better understood as a process whereby a stimulus triggers only the preparation of a response, without necessarily triggering its initiation. Critically, this would allow a habit to exist without ever being overtly expressed, if the prepared habitual response is replaced by a goal-directed alternative before it can be initiated. Consistent with this hypothesis, we show that limiting the time available for response preparation can unmask latent habits. Participants practiced a visuomotor association for 4 days, after which the association was remapped. Participants easily learned the new association but habitually expressed the original association when forced to respond rapidly (~300-600 ms). More extensive practice reduced the latency at which habitual responses were prepared, in turn increasing the likelihood of their being expressed. The time-course of habit expression was captured by a computational model in which habitual responses are automatically prepared at short latency but subsequently replaced by goal-directed responses. Our results illustrate robust habit formation in humans and show that practice affects habitual behaviour in two distinct ways: by promoting habit formation and by modulating the likelihood of habit expression

Age-related increases in reaction time result from slower preparation, not delayed initiation

Recent work indicates that healthy younger adults can prepare accurate responses faster than their voluntary reaction times would suggest, leaving a seemingly unnecessary delay of 80–100 ms before responding. Here, we examined how the preparation of movements, initiation of movements, and the delay between them are affected by aging. Participants made planar reaching movements in two conditions. The “free reaction time” condition assessed the voluntary reaction times with which participants responded to the appearance of a stimulus. The “forced reaction time” condition assessed the minimum time actually needed to prepare accurate movements by controlling the time allowed for movement preparation. The time taken to both initiate movements in the free reaction time and to prepare movements in the forced response condition increased with age. Notably, the time required to prepare accurate movements was significantly shorter than participants’ self-selected initiation times; however,the delay between movement preparation and initiation remained consistent across the lifespan (~90 ms). These results indicate that the slower reaction times of healthy older adults are not due to an increased hesitancy to respond, but can instead be attributed to changes in their ability to process stimuli and prepare movements accordingly, consistent with age-related changes in brain structure and function

Results of N-back tonal task.

<p>(<b><i>A</i></b>, <b><i>B</i></b>) Performance of musicians (<b><i>A</i></b>) and non-musicians (<b><i>B</i></b>) as a function of the notes between the reference and probe notes (N) for quarter note (black curve) and eighth note (grey curve) conditions. (<b><i>C</i></b>) Combined analyses of the quarter and eighth note conditions. Horizontal dashed lines in all plots represent the chance level. Error bars are corrected S.E.M across participants. Stars mark the significant difference comparing to the chance level.</p

t-test analysis for Experiment 2.

<p>t-test analysis for Experiment 2.</p

Comparison between the novel and adjacent notes in the N-back tonal task.

<p>Performance of musicians (<b><i>A</i></b>) and non-musicians (<b><i>B</i></b>) as a function of the notes between the reference and probe notes (N) when the probe note was a novel note (black curve) or identical to a note adjacent to the reference note (grey curve). The performance is plotted as the accuracy (RAU). Horizontal dash lines in all plots represent the chance level. Error bars are corrected S.E.M across participants.</p

Performance across testing stages.

<p>Performance of musicians (gray box) and non-musicians (open box) is plotted for each of the four testing stages. The performance is plotted as the RAU value. Each box represents percentiles of the data. The line within the box indicates the median. Error bars represent the minimums and maximum values. Small circles indicate the outliers. The significant difference between musician and non-musicians groups is indicated by the asteroids above the two boxes for each testing stage. (<b><i>A</i></b>) MTS condition in Experiment 1. Musicians’ performance is significantly higher than non-musicians at all four testing stages. (<b><i>B</i></b>) RTS condition in Experiment 1. No significant difference between musicians and non-musicians. (<b><i>C</i></b>) Experiment 2. Musicians’ performance is significantly higher than non-musicians at stages 1, 2, and 3, but not at stage 4. The significant difference was marked as stars.</p