Publications by authors named "Katy H Stimpson"

9 Publications

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The Hypnotic Induction Profile (HIP) in Clinical Practice and Research.

Int J Clin Exp Hypn 2021 Jan-Mar;69(1):72-82

Stanford University School of Medicine , Palo Alto, California, USA.

The Hypnotic Induction Profile (HIP) was developed as a brief, yet thorough, assessment of a person's level of trait hypnotizability and their potential to experience a hypnotic state. The HIP quantitatively and qualitatively measures hynotizability by evaluating biological and sensorimotor experiences designed to assess 3 fundamental observable and measurable components of hypnosis: absorption, dissociation, and suggestibility through a guided assessment that takes 5 to 10 minutes. From conception, the HIP has been utilized in clinical settings to assess appropriateness for the use of hypnosis in treatment planning and research protocols to stratify research participants. The brevity, accessibility, and reliability of the HIP have allowed it to adapt, not only across settings but through media platforms as technology and remote delivery become increasingly incorporated in the field of hypnosis.
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http://dx.doi.org/10.1080/00207144.2021.1836646DOI Listing
January 2021

Stanford Accelerated Intelligent Neuromodulation Therapy for Treatment-Resistant Depression.

Am J Psychiatry 2020 08 7;177(8):716-726. Epub 2020 Apr 7.

Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, Calif. (all authors), and Department of Psychology (Stimpson, Cherian, Choi, Aaron, Guerra, Phillips), Palo Alto University, Palo Alto, Calif.

Objective: New antidepressant treatments are needed that are effective, rapid acting, safe, and tolerable. Intermittent theta-burst stimulation (iTBS) is a noninvasive brain stimulation treatment that has been approved by the U.S. Food and Drug Administration for treatment-resistant depression. Recent methodological advances suggest that the current iTBS protocol might be improved through 1) treating patients with multiple sessions per day at optimally spaced intervals, 2) applying a higher overall pulse dose of stimulation, and 3) precision targeting of the left dorsolateral prefrontal cortex (DLPFC) to subgenual anterior cingulate cortex (sgACC) circuit. The authors examined the feasibility, tolerability, and preliminary efficacy of Stanford Accelerated Intelligent Neuromodulation Therapy (SAINT), an accelerated, high-dose resting-state functional connectivity MRI (fcMRI)-guided iTBS protocol for treatment-resistant depression.

Methods: Twenty-two participants with treatment-resistant depression received open-label SAINT. fcMRI was used to individually target the region of the left DLPFC most anticorrelated with sgACC in each participant. Fifty iTBS sessions (1,800 pulses per session, 50-minute intersession interval) were delivered as 10 daily sessions over 5 consecutive days at 90% resting motor threshold (adjusted for cortical depth). Neuropsychological testing was conducted before and after SAINT.

Results: One participant withdrew, leaving a sample size of 21. Nineteen of 21 participants (90.5%) met remission criteria (defined as a score <11 on the Montgomery-Åsberg Depression Rating Scale). In the intent-to-treat analysis, 19 of 22 participants (86.4%) met remission criteria. Neuropsychological testing demonstrated no negative cognitive side effects.

Conclusions: SAINT, an accelerated, high-dose, iTBS protocol with fcMRI-guided targeting, was well tolerated and safe. Double-blinded sham-controlled trials are needed to confirm the remission rate observed in this initial study.
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http://dx.doi.org/10.1176/appi.ajp.2019.19070720DOI Listing
August 2020

Association between Anterior Cingulate Neurochemical Concentration and Individual Differences in Hypnotizability.

Cereb Cortex 2020 May;30(6):3644-3654

Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA, USA.

Hypnosis is the oldest form of Western psychotherapy and a powerful evidence-based treatment for numerous disorders. Hypnotizability is variable between individuals; however, it is a stable trait throughout adulthood, suggesting that neurophysiological factors may underlie hypnotic responsiveness. One brain region of particular interest in functional neuroimaging studies of hypnotizability is the anterior cingulate cortex (ACC). Here, we examined the relationships between the neurochemicals, GABA, and glutamate, in the ACC and hypnotizability in healthy individuals. Participants underwent a magnetic resonance imaging (MRI) session, whereby T1-weighted anatomical and MEGA-PRESS spectroscopy scans were acquired. Voxel placement over the ACC was guided by a quantitative meta-analysis of functional neuroimaging studies of hypnosis. Hypnotizability was assessed using the Hypnotic Induction Profile (HIP), and self-report questionnaires to assess absorption (TAS), dissociation (DES), and negative affect were completed. ACC GABA concentration was positively associated with HIP scores such that the higher the GABA concentration, the more hypnotizable an individual. An exploratory analysis of questionnaire subscales revealed a negative relationship between glutamate and the absorption and imaginative involvement subscale of the DES. These results provide a putative neurobiological basis for individual differences in hypnotizability and can inform our understanding of treatment response to this growing psychotherapeutic tool.
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http://dx.doi.org/10.1093/cercor/bhz332DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7232991PMC
May 2020

Application of a Novel Force-Field to Manipulate the Relationship Between Pelvis Motion and Step Width in Human Walking.

IEEE Trans Neural Syst Rehabil Eng 2019 10 19;27(10):2051-2058. Epub 2019 Sep 19.

Motion of the pelvis throughout a step predicts step width during human walking. This behavior is often considered an important component of ensuring bipedal stability, but can be disrupted in populations with neurological injuries. The purpose of this study was to determine whether a novel force-field that exerts mediolateral forces on the legs can manipulate the relationship between pelvis motion and step width, providing proof-of-concept for a future clinical intervention. We designed a force-field able to: 1) minimize the delivered mediolateral forces (Transparent mode); 2) apply mediolateral forces to assist the leg toward mechanically-appropriate step widths (Assistive mode); and 3) apply mediolateral forces to perturb the leg away from mechanically-appropriate step widths (Perturbing mode). Neurologically-intact participants were randomly assigned to either the Assistive group (n = 12) or Perturbing group (n = 12), and performed a series of walking trials in which they interfaced with the force-field. We quantified the step-by-step relationship between mediolateral pelvis displacement and step width using partial correlations. Walking in the Transparent force-field had a minimal effect on this relationship. However, force-field assistance directly strengthened the relationship between pelvis displacement and step width, whereas force-field perturbations weakened this relationship. Both assistance and perturbations were followed by short-lived effects during a wash-out period, in which the relationship between pelvis displacement and step width differed from the baseline value. The present results demonstrate that the link between pelvis motion and step width can be manipulated through mechanical means, which may be useful for retraining gait balance in clinical populations.
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http://dx.doi.org/10.1109/TNSRE.2019.2941372DOI Listing
October 2019

Post-stroke deficits in the step-by-step control of paretic step width.

Gait Posture 2019 05 6;70:136-140. Epub 2019 Mar 6.

Department of Health Sciences and Research, Medical University of South Carolina (MUSC), Charleston, SC, USA; Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC, USA; Division of Physical Therapy, MUSC, Charleston, SC, USA. Electronic address:

Background: Humans partially maintain gait stability by actively controlling step width based on the dynamic state of the pelvis - hereby defined as the "dynamics-dependent control of step width". Following a stroke, deficits in the accurate control of paretic leg motion may prevent use of this stabilization strategy.

Research Question: Do chronic stroke survivors exhibit paretic-side deficits in the dynamics-dependent control of step width?

Methods: Twenty chronic stroke survivors participated in this cross-sectional study, walking on a treadmill at their self-selected (0.57 ± 0.25 m/s; mean ± s.d.) and fastest-comfortable (0.81 ± 0.30 m/s) speeds. To quantify the dynamics-dependent control of step width, we calculated the proportion of the step-by-step variance in step width that could be predicted from mediolateral pelvis dynamics, and used partial correlations to differentiate the relative effects of pelvis displacement and velocity. Secondarily, we calculated the mean and standard deviation of more traditional gait metrics: step width; lateral foot placement; and mediolateral margin of stability (MoS). We used repeated measures ANOVA to test for significant effects of leg (paretic vs. non-paretic) and speed (self-selected vs. fastest-comfortable) on these measures.

Results: Relative to non-paretic steps, paretic steps exhibited a weaker (p ≤ 0.005) link between step width and pelvis dynamics, attributable to a decreased partial correlation between step width and pelvis displacement (p ≤ 0.001). Paretic steps were also placed more laterally (p < 0.0001), with a larger (p < 0.0001) and more variable (p = 0.003) MoS. The only effect of faster walking speeds was a narrower step width (p < 0.0001).

Significance: Pelvis displacement was less tightly linked to step width for paretic steps than for non-paretic steps, indicating a decrease in the step-by-step reactive control normally used to ensure mediolateral stability. Instead, stroke survivors placed their paretic leg farther laterally to ensure a larger MoS, behavior consistent with a greater reliance on a generalized feed-forward gait stabilization strategy.
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http://dx.doi.org/10.1016/j.gaitpost.2019.03.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6474800PMC
May 2019

Effects of walking speed on the step-by-step control of step width.

J Biomech 2018 02 24;68:78-83. Epub 2017 Dec 24.

Department of Health Sciences and Research, Medical University of South Carolina (MUSC), Charleston, SC, USA; Division of Physical Therapy, MUSC, Charleston, SC, USA; Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC, USA. Electronic address:

Young, healthy adults walking at typical preferred speeds use step-by-step adjustments of step width to appropriately redirect their center of mass motion and ensure mediolateral stability. However, it is presently unclear whether this control strategy is retained when walking at the slower speeds preferred by many clinical populations. We investigated whether the typical stabilization strategy is influenced by walking speed. Twelve young, neurologically intact participants walked on a treadmill at a range of prescribed speeds (0.2-1.2 m/s). The mediolateral stabilization strategy was quantified as the proportion of step width variance predicted by the mechanical state of the pelvis throughout a step (calculated as R magnitude from a multiple linear regression). Our ability to accurately predict the upcoming step width increased over the course of a step. The strength of the relationship between step width and pelvis mechanics at the start of a step was reduced at slower speeds. However, these speed-dependent differences largely disappeared by the end of a step, other than at the slowest walking speed (0.2 m/s). These results suggest that mechanics-dependent adjustments in step width are a consistent component of healthy gait across speeds and contexts. However, slower walking speeds may ease this control by allowing mediolateral repositioning of the swing leg to occur later in a step, thus encouraging slower walking among clinical populations with limited sensorimotor control.
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http://dx.doi.org/10.1016/j.jbiomech.2017.12.026DOI Listing
February 2018

Combining therapeutic approaches: rTMS and aerobic exercise in post-stroke depression: a case series.

Top Stroke Rehabil 2018 01 6;25(1):61-67. Epub 2017 Oct 6.

a Department of Health Sciences and Research , Medical University of South Carolina , Charleston , SC , USA.

Objective and importance Residual effects of stroke include well-documented functional limitations and high prevalence of depression. Repetitive transcranial magnetic stimulation (rTMS) and aerobic exercise (AEx) are established techniques that improve depressive symptoms, but a combination of the two has yet to be reported. The purpose of this case series is to examine the safety, feasibility, and impact of combined rTMS and AEx on post-stroke depression and functional mobility. Clinical presentation Three participants with a history of stroke and at least mild depressive symptoms (Patient Health Questionare-9 ≥5). Intervention Both rTMS and AEx were completed 3 times/week for 8-weeks. rTMS was applied to the left dorsolateral prefrontal cortex, 5000 pulses/session at 10 Hz, at an intensity of 120% of resting motor threshold. AEx consisted of 40 min of treadmill walking at 50-70% of heart rate reserve. Results Depressive symptoms improved in all three participants, with all demonstrating response (≥50% improvement in symptoms) and likely remission. All participants improved their Six Minute Walk Test distance and Participants 1 and 2 also improved Berg Balance Scale scores. Participants 1 and 3 improved overground walking speeds. No serious adverse events occurred with the application of rTMS or AEx and the participants' subjective reports indicated positive responses. Adherence rate for both rTMS and AEx was 98%. Conclusion Combined treatment of rTMS and AEx appears safe, feasible, and tolerable in individuals with a history of stroke and at least mild depressive symptoms. All participants had good compliance and demonstrated improvements in both depressive symptoms and walking capacity.
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http://dx.doi.org/10.1080/10749357.2017.1374685DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5801693PMC
January 2018

Effects of hip abduction and adduction accuracy on post-stroke gait.

Clin Biomech (Bristol, Avon) 2017 May 2;44:14-20. Epub 2017 Mar 2.

Ralph H. Johnson VAMC, Charleston, SC, USA; Division of Physical Therapy, Medical University of South Carolina (MUSC), Charleston, SC, USA; Department of Health Sciences and Research, MUSC, Charleston, SC, USA.

Background: Gait instability often limits post-stroke function, although the mechanisms underlying this instability are not entirely clear. Our recent work has suggested that one possible factor contributing to post-stroke gait instability is a reduced ability to accurately control foot placement. The purpose of the present experiments was to investigate whether post-stroke gait function is related to the ability to accurately abduct and adduct the hip, as required for accurate foot placement.

Methods: 35 chronic stroke survivors and 12 age-matched controls participated in this experiment. Participants performed hip oscillation trials designed to quantify hip abduction/adduction accuracy, in which they lay supine and moved their leg through a prescribed range of motion in time with a metronome. Stroke survivors also performed overground walking trials at their self-selected speed.

Findings: 28 of the 35 stroke survivors had sufficient active range of motion to perform the prescribed hip oscillation task. In comparison to controls, these 28 stroke survivors were significantly less accurate at matching the abduction target, matching the adduction target, and moving in time with the metronome. Across these stroke survivors, a multiple regression revealed that only paretic hip abduction accuracy made a unique contribution to predicting paretic step width and paretic step period, metrics of gait performance.

Interpretation: The present results demonstrate that the ability to accurately abduct the hip is related to post-stroke gait performance, as predicted from a model-based gait stabilization strategy. Therefore, interventions designed to improve lower limb movement accuracy may hold promise for restoring post-stroke gait stability.
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http://dx.doi.org/10.1016/j.clinbiomech.2017.02.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5420502PMC
May 2017