Imaging Features of Uncommon Entities That Manifest with Torsion.

Torsion is the twisting of an object along the axis, and various structures (organs and tumors) in the body can twist. Torsion causes initial lymphatic and venous outflow obstruction, leading to congestive edema, enlargement, venous hemorrhagic infarction, and surrounding edema. It can also cause subsequent arterial obstruction depending on the degree of torsion, leading to ischemia, infarction, necrosis, gangrene, and surrounding inflammation. Therefore, in several cases of torsion, immediate surgical intervention is required to improve blood flow and prevent serious complications. Clinical manifestations of torsion are often nonspecific and can affect individuals of varying ages and sex. Imaging plays an important role in the early diagnosis and management of torsion. Multiple imaging modalities, including US, radiography, CT, and MRI, are used to evaluate torsion, and each modality has its specific characteristics. The imaging findings reflect the pathophysiologic mechanism: a twisted pedicle (whirlpool sign), enlargement of the torsed structures, reduced blood flow, internal heterogeneity, and surrounding reactive changes. The whirlpool sign is a definitive characteristic of torsion. In some cases, despite poor internal enhancement, capsular enhancement is observed on contrast-enhanced CT and MR images and is considered to be associated with preserved capsular arterial flow or capsular neovascularization due to inflammation. Radiologists should be familiar with the pathophysiologic mechanisms, clinical characteristics, and imaging characteristics of torsion in various structures in the body. Since other articles about common organ torsions already exist, the authors of this article focus on the uncommon entities that manifest with torsion. ©RSNA, 2024.

Magnetic resonance imaging features of complete androgen insensitivity syndrome in comparison to Mayer-Rokitansky-Küster-Hauser syndrome.

PURPOSE: Complete androgen insensitivity syndrome (CAIS) and Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS) share common clinical features such as female phenotype, vaginal hypoplasia, and primary amenorrhea. Magnetic resonance imaging (MRI) is performed to investigate the cause of primary amenorrhea. However, the MRI features are also similar in both disorders. They are ultimately diagnosed by chromosome testing, but there is a possibility of misdiagnosis if chromosome testing is not performed. This study aimed to identify MRI features that are useful for differentiating CAIS from MRKHS. METHOD: This multicenter retrospective study included 12 patients with CAIS and 19 patients with MRKHS. Three radiologists blindly evaluated the following features: (1) detection of vagina, (2) detection of nodular and cystic structures in the lateral pelvis; undescended testicles and paratesticular cysts in CAIS and rudimentary uteri and ovaries in MRKHS, (3) their location, (4) number of cysts in the cystic structures, and (5) signal intensity on diffusion-weighted images (DWI) and apparent diffusion coefficient (ADC) values of the nodular structures. Statistical comparisons were performed using Mann-Whitney U and Fisher's exact tests. RESULTS: Compared with MRKHS, the CAIS group showed significantly detectable vagina, more ventrally located nodular and cystic structures, fewer cysts within the cystic structures, and nodular structures with higher signal intensity on DWI and lower ADC values. CONCLUSIONS: MRI features of detectable vagina, location of nodular and cystic structures, number of cysts within the cystic structures, signal intensity on DWI and ADC values of the nodular structures were useful in differentiating CAIS from MRKHS.

Effect of rechallenge nivolumab in a hemodialysis patient with multiple metastases from a rapidly progressed T1a renal clear cell carcinoma: An autopsy case.

Introduction: Distant metastasis of T1a renal cell carcinoma is rare and whether metastasis is more probable in patients undergoing hemodialysis remains unclear. We report the autopsy case of a patient undergoing hemodialysis with multiple metastases that rapidly progressed from T1a renal cell carcinoma treated with multimodal therapy including nivolumab. Case presentation: A 70-year-old male who underwent hemodialysis was diagnosed with clear cell carcinoma (pT1a, G2) after nephrectomy. Six months post-surgery, bone and lung metastases appeared and treated with radiotherapy and pazopanib, respectively. Nivolumab was administered as second- and fourth-line treatments for lung metastases. The patient died approximately 60 months after initial diagnosis; however, nivolumab controlled disease progression for 24 months. An autopsy revealed the lung's occupation with clear cell carcinoma tumor tissue. Conclusion: Nivolumab has potential to control lung metastasis progression. Additionally, rechallenge is possible in patients with renal cell carcinoma undergoing hemodialysis.

Prediction of antenatal bleeding and preterm deliveries using placental magnetic resonance imaging in patients with placenta previa.

PURPOSE: This study aimed to clarify associations between subacute hematoma on placental magnetic resonance imaging (MRI), antenatal bleeding, and preterm deliveries in patients with placenta previa (PP) without placenta accreta spectrum (PAS). MATERIALS AND METHODS: This retrospective study investigated 78 consecutive patients with PP (median age, 34.5 years; interquartile range [IQR], 31-37 years) who underwent placental MRI in the third trimester. Patients with PAS detected intraoperatively or pathologically were excluded. Two radiologists evaluated the presence of subacute hematomas and their locations on placental MRI. We examined associations between presence of subacute hematoma and antenatal bleeding, emergency cesarean section (CS), hysterectomy, gestational age (GA) at delivery, birth weight, and amount of blood loss at CS. We also examined the association between perinatal outcome and subacute hematoma location: marginal, retro-placental, or intra-placental. Inter-observer agreement for the detection of subacute hematoma was calculated using kappa analysis. RESULTS: Subacute hematomas were identified on MRI in 39 of the 78 patients (50.0%). Antenatal bleeding and emergency CS were more prevalent in patients with subacute hematoma on MRI (20 patients [51.3%] and 18 patients [46.2%], respectively) than in patients without (7 patients [17.9%], Fisher's exact test, p = 0.004 and 7 patients [17.9%], p = 0.014, respectively). GA at delivery was significantly lower in patients with subacute hematoma (median 36w3d, IQR 35w4d-37w1d) than in patients without (median 37w1d, IQR 36w4d-37w2d; Mann-Whitney test: p = 0.048). Marginal hematoma was significantly associated with antenatal bleeding and emergency CS. Inter-observer agreement for the presence of subacute hematoma was moderate (κ = 0.573). CONCLUSION: Subacute hematoma on placental MRI was associated with antenatal bleeding, emergency CS and shorter GA at delivery in patients with PP. Marginal hematoma was also associated with antenatal bleeding and emergency CS. Placental MRI appears useful for predicting antenatal bleeding and preterm delivery in patients with PP.

Hypopituitarism induced by pembrolizumab plus axitinib in the treatment of metastatic renal cell carcinoma: A case report.

Immune checkpoint inhibitor (ICI) therapies have broadened the armamentarium for metastatic renal cell carcinoma (mRCC). As the ICI therapy spreads in the clinical settings, immune-related adverse events are more of a concern for clinicians. The present study reports three cases of mRCC treated with pembrolizumab plus axitinib and diagnosed hypopituitarism based on clinical symptoms and hormonal profile. Acute methylprednisolone infusion therapy was necessary in one case because of severe adrenal hypofunction; however, the clinical symptoms of the other two cases were controlled with oral corticosteroid therapy. To the best of our knowledge, there is no report of pembrolizumab plus axitinib related hypopituitarism in the treatment of mRCC. The present cases suggests that hypopituitarism after pembrolizumab plus axitinib treatment for mRCC can be handled with steroid therapy even after the development of hypopituitarism.

Mental health of health professionals and their perspectives on mental health services in a conflict-affected setting: a qualitative study in health centres in the Gaza Strip during the COVID-19 pandemic.

OBJECTIVES: To explore how primary care health professionals perceive their own mental health in a conflict-affected setting during and beyond the COVID-19 pandemic and to explore their perspectives on mental health services. METHODS: The Gaza Strip faces a chronic humanitarian crisis and is suffering from the consequences of the COVID-19 pandemic; United Nations Relief and Works Agency (UNRWA) health centres were used to recruit participants for this study. Semistructured interviews were conducted with 29 health professionals in UNRWA health centres who were sampled using maximum variation sampling. Transcripts were translated, double checked and analysed via thematic analysis. RESULTS: From the analysis, a thematic map was developed showing how health professionals perceive their mental health impacts. This included difficulties due to the COVID-19 pandemic, as well as the socioeconomic processes stemming from the on-going conflict.Another thematic map was developed showing the perceived strengths and challenges of the health services. The strengths included positive impact of the services to the service users and health professionals. In terms of challenges, health professionals identified socioeconomic processes and aspects of remote service provision during COVID-19. CONCLUSIONS: Based on the findings, we suggest that an improved signposting mechanism should be developed to address many of the challenges that emergencies bring about; in particular, this could support the health professionals' mental health, as well as improve the response to patients' socioeconomic challenges. We further suggest recommendations for improving mental health services when delivered remotely to increase their resiliency during various emergencies.

Influence of vibrotactile random noise on the smoothness of the grasp movement in patients with chemotherapy-induced peripheral neuropathy.

Patients with chemotherapy-induced peripheral neuropathy (CIPN) often suffer from sensorimotor dysfunction of the distal portion of the extremities (e.g., loss of somatosensory sensation, numbness/tingling, difficulty typing on a keyboard, or difficulty buttoning/unbuttoning a shirt). The present study aimed to reveal the effects of subthreshold vibrotactile random noise stimulation on sensorimotor dysfunction in CIPN patients without exacerbating symptoms. Twenty-five patients with CIPN and 28 age-matched healthy adults participated in this study. To reveal the effects of subthreshold vibrotactile random noise stimulation on sensorimotor function, participants were asked to perform a tactile detection task and a grasp movement task during random noise stimulation delivered to the volar and dorsal wrist. We set three intensity conditions of the vibrotactile random noise: 0, 60, and 120% of the sensory threshold (Noise 0%, Noise 60%, and Noise 120% conditions). In the tactile detection task, a Semmes-Weinstein monofilament was applied to the volar surface of the tip of the index finger using standard testing measures. In the grasp movement task, the distance between the thumb and index finger was recorded while the participant attempted to grasp a target object, and the smoothness of the grasp movement was quantified by calculating normalized jerk in each experimental condition. The experimental data were compared using two-way repeated-measures analyses of variance with two factors: experimental condition (Noise 0, 60, 120%) × group (Healthy controls, CIPN patients). The tactile detection threshold and the smoothness of the grasp movement were only improved in the Noise 60% condition without exacerbating numbness/tingling in CIPN patients and healthy controls. The current study suggested that the development of treatment devices using stochastic resonance can improve sensorimotor function for CIPN patients.

A Case of Ruptured Decidualized Ovarian Endometrioma: Usefulness of Serial MRI for Determining Adequate Management.

Decidualization can originate in ovarian endometrioma by elevated serum progesterone levels during pregnancy, which mimics malignancy on ultrasonography. Moreover, decidualized ovarian endometrioma may rupture and cause acute abdominal pain during pregnancy. Magnetic resonance imaging (MRI) is reportedly useful in differentiating decidualized ovarian endometriomas from malignancies. However, to our knowledge, serial MRI of decidualized ovarian endometrioma before and after rupture has not been reported. Herein, we report the case of a 39-year-old woman with a ruptured decidualized ovarian endometrioma in which serial MRI was useful for adequate management. She had a history of right ovarian endometrioma. Transvaginal ultrasonography at 20 weeks of gestation showed the known right ovarian endometrioma with mural nodules that were not evident before pregnancy. MRI for further evaluation showed ovarian endometrioma with mural nodules with signals similar to those of the placenta. Based on the MRI findings, we diagnosed a decidualized ovarian endometrioma. At 27 weeks of gestation, she complained of sudden abdominal pain, for which MRI was performed. MRI showed disappearance of the ovarian endometrioma and bloody ascites, based on which we diagnosed a ruptured ovarian endometrioma. The abdominal pain subsided immediately, and a conservative observational treatment approach was taken. At 37 weeks of gestation, right ovarian cystectomy was performed simultaneously with an elective cesarean section, which revealed a ruptured decidualized ovarian endometrioma. Our findings demonstrate that the accurate diagnosis of a ruptured decidualized ovarian endometrioma on serial MRI can contribute to its management.

Participants' experiences of engagement in community-centred mental health and psychosocial support programmes in conflict-affected communities within sub-Saharan Africa: a qualitative systematic review.

BACKGROUND: Sub-Saharan Africa (SSA) experienced a burden of organised violence within 18 low-income and middle-income countries and hosted over 33 million displaced persons in 2019. Community-centred mental health and psychosocial support (cc-MHPSS) programmes may provide insights to address the psychosocial well-being of conflict-affected individuals, though literature is mixed on community impact. This review aimed to synthesise qualitative evidence to understand the kind of experiences conflict-affected participants have and how these experiences occur during cc-MHPSS programme engagement in SSA. METHODS: We searched Global Health, MEDLINE, Psychological Information Database, Embase Classic+Embase, Social Policy and Practice, Web of Science, Africa-Wide Information, PubMed and Global Index Medicus databases. Eligible publications qualitatively reported on conflict-affected participants' experiences of engagement in cc-MHPSS programmes. Data were extracted to summarise publication characteristics. The results were synthesised using a thematic synthesis analysis. RESULTS: The search yielded 953 records, of which 20 publications were included in the review. Included publications were located in Rwanda (n=8), the Democratic Republic of the Congo (n=3), Mozambique (n=3), Sierra Leone (n=1), Ghana (n=1), Uganda (n=1), Zimbabwe (n=1) and South Sudan (n=1); one publication included three countries (Sierra Leone, Liberia and Uganda). Findings include the themes of (1) the experience of change in time and space, and (2) the sharing and silence of participants' experiences. Findings demonstrate that elements transferred by participants from a cc-MHPSS programme to a natural community, and vice versa, contribute to participants' healing. Elements' transfer, or non-transfer, was often related to participants' disclosure, or non-disclosure, of experiences. DISCUSSION: Findings suggest that there are elements from a cc-MHPSS programme and a wider community which aid participant engagement and work therapeutically. More rigorous research is needed concerning how participants experience change during cc-MHPSS programme engagement in proximity to their relationship with the wider community. PROSPERO REGISTRATION NUMBER: CRD42020197300.

Local experience of using traditional medicine in northern Rwanda: a qualitative study.

BACKGROUND: The popular use of traditional medicine in low-income settings has previously been attributed to poverty, lack of education, and insufficient accessibility to conventional health service. However, in many countries, including in Rwanda, the use of traditional medicine is still popular despite the good accessibility and availability of conventional health services. This study aims to explore why traditional medicine is popularly used in Rwanda where it has achieved universal health coverage. METHODS: The qualitative study, which included in-depth interviews and participant observations, investigated the experience of using traditional medicine as well as the perceived needs and reasons for its use in the Musanze district of northern Rwanda. We recruited 21 participants (15 community members and 6 traditional healers) for in-depth interviews. Thematic analysis was conducted to generate common themes and coding schemes. RESULTS: Our findings suggest that the characteristics of traditional medicine are responding to community members' health, social and financial needs which are insufficiently met by the current conventional health services. Participants used traditional medicine particularly to deal with culture-specific illness - uburozi. To treat uburozi appropriately, referrals from hospitals to traditional healers took place spontaneously. CONCLUSIONS: In Rwanda, conventional health services universally cover diseases that are diagnosed by the standard of conventional medicine. However, this universal health coverage may not sufficiently respond patients' social and financial needs arising from the health needs. Given this, integrating traditional medicine into national health systems, with adequate regulatory framework for quality control, would be beneficial to meet patients' needs.

Sociality and temporality in local experiences of distress and healing: Ethnographic research in northern Rwanda.

Prior studies have traced sociality and temporality as significant features of African healing. However, association between the two has not been explicitly investigated. This paper explores how sociality and temporality are associated in local experiences of distress and healing among northern Rwandans. The ethnographic research, including in-depth interviews, focus-group discussions and participant observation, was conducted in 2015-2016, with 43 participants from the Musanze district who have suffered from not only the genocide but also post-genocide massacres. Findings identified common local idioms of distress: ibikomere (wounded feelings), ihungabana (mental disturbances), ihahamuka (trauma), and kurwara mu mutwe (illness of the head, severe mental illness). One stage of distress was perceived to develop into another, slightly more serious than the previous. Social isolation played a significant role in the development as it activated 'remembering' and 'thinking too much' about the past and worsened symptoms. Subsequently, healing was experienced through social reconnection and a shift of time orientation from the past to the future; the healing experience traced a process of leaving the past behind, moving forwards and creating a future through community involvement. The experiences of distress and healing in this population were explained by two axes, i.e. sociality (isolation - reconnection) and temporality (past - future), which are associated with each other. Given the sociality-temporality association in African post-war healing, the study highlights that assistant programmes that facilitate social practice and future creation can be therapeutic and be an alternative for people who cannot benefit from talking-based and trauma-focused approaches.

Linking coping strategies to locally-perceived aetiologies of mental distress in northern Rwanda.

INTRODUCTION: How and why people in a particular setting turn to a specific coping strategy for their distress is pivotal for strengthening mental healthcare and this needs to be understood from a local point of view. Prior research in northern Rwanda documented common local concepts of distress for the population that cannot receive assistance despite severe adversities; however, the locally-perceived causes, manifestation and coping strategies and their associations are still unclear. METHODS: The qualitative study in the Musanze district, northern Rwanda, was informed by Interpretative Phenomenological Analysis. In-depth interviews were conducted with people with lived experience and those in close contact with people with lived experience of distress. Ethnographic observation was conducted and the analyses were complimented by an earlier ethnography in the same village. RESULTS: Study participants (n=15) included community members with lived experience of mental distress and/or those with close friends or family with lived experience. The perceived manifestations of the mental distresses were diverse and the causal attributions shifted from more social, concrete and explainable (eg, loss) towards magical, more abstract and unexplainable (eg, poisoning). Finally, participants sought coping strategies in accordance with their causal attribution in ways that made sense to them. CONCLUSION: The coping strategies were chosen according to the perceived aetiology of the symptoms and they were perceived to be effective for their distress. Local coping strategies that match people's help-seeking patterns should therefore be supported in policy and programmes. In Rwanda this requires a mutual training of medical professionals and traditional healers and establishing co-treatment within two parallel systems. This also requires the support for programmes and initiatives that strengthen positive interactions and change in circumstances.

Correction to: Kinesiophobia modulates lumbar movements in people with chronic low back pain: a kinematic analysis of lumbar bending and returning movement.

In the figure 2, "CLBP Low fear" located at the right end of Time of Phase 1 is wrong. The correct statement is "CLBP High fear". The complete correct figure 2 is given below.

Kinesiophobia modulates lumbar movements in people with chronic low back pain: a kinematic analysis of lumbar bending and returning movement.

PURPOSE: We aimed to kinematically analyze lumbar bending and returning movements and clarify the relationship between fear of movement and kinematic output. METHODS: We recruited 45 participants with CLBP (i.e., > 6 months) and 20 healthy control (HC) participants with no history of CLBP. We used the numerical rating pain scale (NRS), Tampa Scale for Kinesiophobia (TSK-11), and Pain Self-Efficacy Questionnaire (PSEQ-2) as qualitative outcome measurements. CLBP participants were divided into two subgroups (high- and low-fear groups) based on the median split of the total TSK-11 score. In the kinematic recording session, a starting-cue beep signaled participants to bend forward using the lumbar region of their spine and then return to an upright posture, and we used a flexible twin-axis electrogoniometer to record the lumbar movements. The time series of lumbar movements was divided into four phases according to lumbar movement velocity, and we calculated the length (sec) of each phase. RESULTS: Phase 1 (duration prior to cue-induced movement initiation) and phase 3 (switch in the direction of lumbar movement from forward to backward) were significantly longer in the CLBP high-fear group compared with those in the CLBP low-fear group and HC group (p < 0.05). The increased lengths of these two phases were positively correlated with not only pain intensity but also TSK-11 scores (p < 0.05). CONCLUSIONS: These results represent evidence of a particular lumbar movement pattern associated with kinesiophobia. These results might help to identify psychological factors that impact lumbar movement patterns in individuals with CLBP. These slides can be retrieved under Electronic Supplementary Material.

Suffering of silenced people in northern Rwanda.

To contribute to understanding the association between silence and suffering in the context of war and political repression, this study sheds light on the meaning-making process and explores the underlying mechanisms by which silence leads to suffering and how this suffering could be alleviated. The ethnographic research was conducted in 2015-2016, with 43 participants from northern Rwanda, who survived massacres after the 1994 genocide but were prevented from speaking about the experience by political constraints. The findings first describe their suffering, through grief, social isolation and loss of meaning in life and death (expressed as existential questions). Their suffering was worsened by 'unspeakability'; that is, the political context that prevents victims from speaking freely about their war experience, including discussion of those who killed and those who were killed. Unspeakability exacerbated suffering since participants were obstructed from applying ready narratives (e.g. funerary rituals, traditional reconciliation systems) or constructing their own narratives which could ordinarily help them to process mourning and reconciliation and to make sense of the loss. They selectively employed silence for coping and protection, avoiding speaking about the past to maintain everyday life. However, at the same time, unprocessed mourning remained a serious problem, resulting in mental health problems such as hallucinations of the spirits of the dead; participants expressed a strong need for mourning rituals. Overall, this paper highlights the ways in which the suffering of the silenced population worsens when meaning-making processes are obstructed. To alleviate the suffering, it is essential to secure mourning rituals for all survivors, particularly those who, as part of the defeated group of war, are silenced and marginalized in history.

Kinematic evaluation for impairment of skilled hand function in chemotherapy-induced peripheral neuropathy.

INTRODUCTION: Chemotherapy-induced peripheral neuropathy (CIPN) usually affects both sensory and motor function of hands and feet, resulting in impaired skilled hand function (e.g., typing a keyboard). However, quantitative and objective evaluations for this condition have not been established. PURPOSE OF THE STUDY: We evaluated skilled hand function using a kinematic analysis and investigated relationships among hand kinematic function and the clinical sensory and motor features of CIPN. STUDY DESIGNS: Clinical measurement. METHODS: Twelve CIPN patients and 12 age-matched control participants were enrolled. We recorded their reach and grasp movements using a three-dimensional measurement system, and calculated the normalized jerk of these movements as quantitative indexes of skilled hand function. Additionally, we used the number of sequential hand grip-release cycles in 10 seconds as an evaluation of clinical motor function. RESULTS: Our kinematic analyses revealed significant difference in normalized jerk of grasp movement (CIPN: 3.7 ± 0.2, control: 3.4 ± 0.1; P = .005), but this was not the case for reach movement (CIPN: 2.5 ± 0.1, control: 2.5 ± 0.2; P = .43), indicating that the distal part of the forearm is particularly affected in CIPN. Such disturbed grasp movement was directly correlated with poor scores on the hand grip-release test and the sensory tests. DISCUSSION: We revealed deficit impaired hand function objectively and quantitatively in CIPN patients using a kinematic analysis. Further, the hand grip test could represent such kinematic abnormality and could be useful for evaluating skilled hand function of CIPN patients. CONCLUSIONS: Our kinematic and clinical measurements objectively and quantitatively evaluate skilled hand function in individuals with CIPN in clinical settings. LEVEL OF EVIDENCE: Cross-sectional observational study.

Magnetic resonance imaging of the human placental cotyledon: Proposal of a novel cotyledon appearance score.

OBJECTIVE: To determine the magnetic resonance imaging (MRI)-detectable morphology of the placental cotyledon, we proposed the first cotyledon appearance scores on MRI. Cotyledon appearance scores consist of two subscores: orthogonal and parallel cotyledon appearance scores. These represent cotyledon appearance orthogonal or parallel to the placental thickness, respectively. STUDY DESIGN: This retrospective study was approved by the institutional review board of our hospital. A total of 51 placentas were studied. Two MRI specialists independently evaluated the two cotyledon appearance subscores at various gestational ages. Scores were related to gestational age. RESULTS: Cotyledons were not evident in the 2nd trimester, but were identified in the 3rd trimester. Cotyledon appearance subscores increased according to gestational age, with subscores showing good inter-observer agreement. CONCLUSION: Cotyledon appearance scores determined that placental cotyledons became evident on MRI, suggesting that placental maturity progressed with gestational age. These placental MRI findings may serve as references for placental MRI to detect placental abnormalities.

Characteristics of Phantom Limb Pain Alleviated with Virtual Reality Rehabilitation.

OBJECTIVES: Neurorehabilitation techniques using virtual reality (VR) systems have recently become widespread as a rehabilitation method for restoring phantom limb movement and alleviating phantom limb pain (PLP). However, analgesic effects have varied between studies, possibly because of differences in the characteristics of PLP between patients (e.g., cramping, burning, shooting). We aimed to reveal the relationship between VR effects and PLP characteristics using an exploratory factor analysis. METHODS: PLP characteristics of 19 patients were measured using the Short-Form McGill Pain Questionnaire (SF-MPQ), and all PLP patients performed the VR rehabilitation protocol for 20 minutes. During VR rehabilitation, mirror-reversed computer graphic images of an intact arm (the virtual phantom limb) were presented to patients via a head-mounted display, inducing the perception of voluntary execution of movements of their phantom limb when intending bimanual movements. RESULTS: VR rehabilitation significantly restored movement representation (P < 0.0001) quantified using the bimanual coupling effect and significantly alleviated PLP intensity (P < 0.0001). The factor analysis revealed that PLP characteristics could be divided into two factors: "somatosensory-related pain characteristics" and "kinesthesia-related pain characteristics." PLP alleviation via VR rehabilitation was significantly correlated with "kinesthesia-related pain characteristics" (r = 0.47, P = 0.02) but not "somatosensory-related pain characteristics" (r = 0.22, P = 0.17). CONCLUSIONS: The current findings indicate that VR rehabilitation may be particularly effective for PLP associated with distorted phantom limb movement and body representations (e.g., clamping, gnawing), compared with typical neuropathic sensations (e.g., shooting, burning, dysesthesia).

A hypothetical explanatory sensorimotor model of bilateral limb interference.

Goal-directed movements of a limb are optimized by sensorimotor integration, a process that merges both sensory and motor representations. In a previous study, we revealed that abnormal sensory representation can impair reach-to-grasp movements in patients with spinothalamocortical pathway lesions. This abnormal motor control was significantly recovered when referencing correct somatosensory information with the intact hand. Furthermore, motor control of the intact hand was impaired when referencing abnormal somatosensory information with the affected hand. Such bilateral limb interference suggests that there is only one common integrated sensory representation and only one common motor representation for both hands. The single sensory representation would be integrated from the somatosensory information received from both hands. Subsequently, the integrated motor representation would be derived from the integrated sensory representation, and would then be split and sent out via motor commands to both hands. Considering that bimanual coordinated movements are reportedly smoother than unimanual movements, information transfer between the integrated sensory and the integrated motor representation would be suitable for such efficient bimanual movements. Therefore, we propose a novel hypothetical model to better explain the observation of bilateral limb interference. The proposed model might contribute to the development of novel sensory and motor rehabilitation strategies by promoting the use of the unaffected hand.