Changes in the excitability of anterior horn cells in a mental rotation task of body parts.

INTRODUCTION/AIMS: Mental rotation (MR), a tool of implicit motor imagery, is the ability to rotate mental representations of two- or three-dimensional objects. Although many reports have described changes in brain activity during MR tasks, it is not clear whether the excitability of anterior horn cells in the spinal cord can be changed. In this study, we examined whether MR tasks of hand images affect the excitability of anterior horn cells using F-wave analysis. METHODS: Right-handed, healthy participants were recruited for this study. F-waves of the right abductor pollicis brevis were recorded after stimulation of the right median nerve at rest, during a non-MR task, and during an MR task. The F-wave persistence and the F/M amplitude ratio were calculated and analyzed. RESULTS: Twenty participants (11 men and 9 women; mean age, 29.2 ± 4.4 years) were initially recruited, and data from the 18 that met the inclusion criteria were analyzed. The F-wave persistence was significantly higher in the MR task than in the resting condition (p = .001) or the non-MR task (p = .012). The F/M amplitude ratio was significantly higher in the MR task than in the resting condition (p = .019). DISCUSSION: The MR task increases the excitability of anterior horn cells corresponding to the same body part. MR tasks may have the potential for improving motor function in patients with reduced excitability of the anterior horn cells, although this methodology must be further verified in a clinical setting.

Differences in working memory function are associated with motor imagery-induced changes in spinal motor nerve excitability and subsequent motor skill changes.

Verification of the effectiveness of motor imagery (MI) has mainly focused on the method of implementing MI, and few studies have assessed individual factors. This study examined the individual differences in MI effects from the viewpoint of the multiple components of working memory. Forty-six healthy subjects (mean age 20.8 years) performed the Stroop Test (central executive within working memory) and reverse chanting (phonological loop within working memory). Then, F-waves were measured at rest for 30 s, the Purdue Pegboard was performed with the non-dominant hand to evaluate finger dexterity (Peg score) before MI, F-waves were measured during 30 s of kinesthetic MI, and the Peg score was evaluated after MI. For statistical analysis, the amplitude F/M ratio and Peg score were used as dependent variables, and the subjects were divided into Good and Poor groups according to cognitive function. The results showed an interaction for the amplitude F/M ratio and Peg score when grouped by reverse inverse chanting. In the subsequent simple main effect analysis, the Peg score was significantly improved after MI in both groups. The amplitude F/M ratio was significantly increased during MI compared to the resting state only in the Poor phonological loop group. Conversely, there was no interaction when the groups were divided by Stroop interference. No relationship was found between individual differences in central executive and changes in hand finger dexterity and spinal motor nerve excitability induced by MI. However, there may be a relationship between individual differences in phonological loops and changes in MI-induced finger dexterity and spinal motor nerve excitability.

Unilateral vibration stimulation decreases F-wave persistence and F/M amplitude ratio in contralateral homonymous muscle corresponding to the stimulated muscle during stimulation.

[Purpose] This study aimed to examine the effects of unilateral vibratory stimulation on contralateral homonymous muscle. [Participants and Methods] The study included 14 participants without a history of any disease. Participants were tested under three separate conditions: vibratory stimulation, pressure stimulation, and rest. F-waves were measured at two time points for 15 seconds in the rest position under each of the testing conditions. [Results] The F/M amplitude ratio analysis showed interactions between the vibratory stimulation‒pressure stimulation and vibratory stimulation‒rest conditions. The F-wave persistence analysis demonstrated interactions between the vibratory and pressure stimulation conditions. Vibratory stimulation significantly decreased the F/M amplitude ratio and F-wave persistence at two time points, before and during the stimulation. [Conclusion] The vibratory stimulation used in this study could suppress the contralateral homonymous muscle tone.

Pain reduction method in recording F-waves from the vastus lateralis muscle.

INTRODUCTION/AIMS: Conventional recording of F-waves from the vastus lateralis muscle causes severe pain in some subjects. Thus, we aimed to investigate the effects of the stimulation frequency on pain and F-wave parameters when recording F-waves from this muscle and to develop a method for recording F-waves from the vastus lateralis muscle that causes minimal pain. METHODS: The subject's femoral nerve was electrically stimulated at 0.5 or 0.2 Hz 30 times, while F-waves were recorded from the vastus lateralis muscle. Pain intensity was measured immediately using a visual analog scale. In addition, the visual analog scale, F-wave persistence, F-wave latency, and F/M amplitude ratio were compared between F-wave recordings with 0.5-Hz electrical stimulation and those with 0.2-Hz electrical stimulation. RESULTS: Eleven healthy men participated in this study. The visual analog scale and F-wave persistence decreased when electrical stimulation at 0.2 Hz was applied compared with electrical stimulation at 0.5 Hz. DISCUSSION: Electrical stimulation at 0.5 Hz increased pain due to temporal summation. However, electrical stimulation at 0.2 Hz did not cause temporal summation, suggesting reduced pain and excitability of the alpha motor neuron pool.

Decreased nerve conduction velocity may be a predictor of fingertip dexterity and subjective complaints.

We examined the causes of decreased fingertip dexterity in elderly individuals with an aim to improve their quality of life by improving their activities of daily living. We calculated nerve conduction velocity, absolute error during force adjustment tasks, and fingertip dexterity test scores for 30 young (21-34 years old) and 30 elderly (60-74 years old) participants to identify age-related changes. We also assessed subjective complaints of pain, motor function, and numbness. Motor nerve (young: 55.8 ± 3.7 m/s; elderly: 52.2 ± 5.0 m/s) and sensory nerve (young: 59.4 ± 3.4 m/s; elderly: 55.5 ± 5.3 m/s) conduction velocities decreased in an age-dependent manner. Moreover, the decrease of motor nerve conduction velocity was associated with decreased fingertip dexterity (objective index), while the decrease of sensory nerve conduction velocity was associated with subjective complaints of pain and motor function (subjective index).

Mizoribine halts kidney fibrosis in childhood IgA nephropathy: association with modulation of M2-type macrophages.

BACKGROUND: The immunosuppressant mizoribine (Miz) can reduce progression of childhood IgA nephropathy (IgAN). This study examined whether Miz affects CD163+ M2-type macrophages which are associated with kidney fibrosis in childhood IgAN. METHODS: A retrospective cohort of 90 children with IgAN were divided into groups treated with prednisolone (PSL) alone (P group; n = 42) or PSL plus Miz (PM group; n = 48) for a 2-year period. Normal human monocyte-derived macrophages were stimulated with dexamethasone (Dex), or Dex plus Miz, and analyzed by DNA microarray. RESULTS: Clinical and histological findings at first biopsy were equivalent between patients entering the P and PM groups. Both treatments improved proteinuria and haematuria, and maintained normal kidney function over the 2-year course. The P group exhibited increased mesangial matrix expansion, increased glomerular segmental or global sclerosis, and increased interstitial fibrosis at 2-year biopsy; however, the PM group showed no progression of kidney fibrosis. These protective effects were associated with reduced numbers of glomerular and interstitial CD163+ macrophages in the PM versus P group. In cultured human macrophages, Dex induced upregulation of cytokines and growth factors, which was prevented by Miz. Miz also inhibited Dex-induced expression of CD300E, an activating receptor which can prevent monocyte apoptosis. CD300e expression by CD163+ macrophages was evident in the P group, which was reduced by Miz treatment. CONCLUSION: Miz halted the progression of kidney fibrosis in PSL-treated pediatric IgAN. This was associated with reduced CD163+ and CD163+CD300e+ macrophage populations, plus in vitro findings that Miz can suppress steroid-induced macrophage expression of pro-fibrotic molecules. A higher resolution version of the Graphical abstract is available as Supplementary information.

Congenital hearing impairment associated with peripheral cochlear nerve dysmyelination in glycosylation-deficient muscular dystrophy.

Hearing loss (HL) is one of the most common sensory impairments and etiologically and genetically heterogeneous disorders in humans. Muscular dystrophies (MDs) are neuromuscular disorders characterized by progressive degeneration of skeletal muscle accompanied by non-muscular symptoms. Aberrant glycosylation of α-dystroglycan causes at least eighteen subtypes of MD, now categorized as MD-dystroglycanopathy (MD-DG), with a wide spectrum of non-muscular symptoms. Despite a growing number of MD-DG subtypes and increasing evidence regarding their molecular pathogeneses, no comprehensive study has investigated sensorineural HL (SNHL) in MD-DG. Here, we found that two mouse models of MD-DG, Largemyd/myd and POMGnT1-KO mice, exhibited congenital, non-progressive, and mild-to-moderate SNHL in auditory brainstem response (ABR) accompanied by extended latency of wave I. Profoundly abnormal myelination was found at the peripheral segment of the cochlear nerve, which is rich in the glycosylated α-dystroglycan-laminin complex and demarcated by "the glial dome." In addition, patients with Fukuyama congenital MD, a type of MD-DG, also had latent SNHL with extended latency of wave I in ABR. Collectively, these findings indicate that hearing impairment associated with impaired Schwann cell-mediated myelination at the peripheral segment of the cochlear nerve is a notable symptom of MD-DG.

Optimal stimulation site of the femoral nerve to record F waves from the vastus lateralis muscle.

INTRODUCTION/AIMS: The conventional recording of F waves from the vastus lateralis muscle (VL) may not accurately measure the F-wave amplitude, as the F-wave latency is short and overlaps with the M wave. However, the optimal stimulation site of the femoral nerve for recording M and F waves separately from the VL remains unclear. In this study we aimed to determine the optimal stimulation site of the femoral nerve to record M and F waves separately from the VL. METHODS: Stimulating electrodes were placed medial and lateral to the VL (50%, 60%, 70%, and 80% of the distance along a line extending from the proximal to the distal thigh). Each site of the distal thigh was electrically stimulated at random and F waves were recorded from the VL. Each stimulation site was considered to be success if there was no severe pain or discomfort during electrical stimulation of the femoral nerve and no overlap between the recorded M and F waves; otherwise, it was determined as a failure. RESULTS: Thirteen healthy men participated in the study. F waves were successfully recorded in five participants at the 50% sites, eight participants at the 60% site, and 12 participants at the 70% and 80% sites. In cases of failed F-wave measurement, the participants experienced severe pain or discomfort due to electrical stimulation. DISCUSSION: M and F waves could be recorded separately from the VL when the relevant branch of the femoral nerve was stimulated in the distal thigh.

Feasibility, Safety, and Long-Term Outcomes of Zero-Contrast Percutaneous Coronary Intervention in Patients With Chronic Kidney Disease.

BACKGROUND: The long-term safety and utility of intravascular ultrasound (IVUS)-guided zero-contrast percutaneous coronary intervention (PCI) in patients with chronic kidney disease (CKD) are unknown.Methods and Results: A total of 698 consecutive patients treated with PCI (1,061 procedures) in our center were studied. Patients with acute coronary syndrome, who are on maintenance hemodialysis, and who had a planned rotational atherectomy were excluded. Finally, they were divided into 2 groups: zero-contrast PCI (n=55, 78 procedures) and conventional PCI (n=462, 670 procedures). After propensity score matching, 50 patients were matched for each group to evaluate long-term outcomes. Primary endpoints were major adverse cardiovascular events (MACE), including all-cause death, non-fatal myocardial infarction (MI), and clinically driven target lesion revascularization. All patients in the zero-contrast PCI group had stage 3-5 CKD with an estimated glomerular filtration rate of 38.3±14.8 mL/min/1.73 m2. Zero-contrast PCI was successful in all 78 procedures without renal events such as acute kidney injury or emergent hemodialysis and procedural complications such as coronary perforation or periprocedural MI. During a follow-up period of 32 months, 7 patients died (1 cardiac, 6 non-cardiovascular), and 4 patients were introduced to renal replacement therapy. The incidence of MACE was similar between the zero-contrast and conventional PCI groups (log-rank, P=0.95). CONCLUSIONS: IVUS-guided zero-contrast PCI might be safe and feasible in patients with CKD with satisfactory acute and long-term renal and cardiovascular outcomes.

Relationship between hand-behind-back motion and internal rotation with the shoulder in extension.

[Purpose] The purpose of the present study was to investigate whether the extent of shoulder internal rotation measured in the extended position of the shoulder could be a good indicator of hand-behind-back motion ability. [Participants and Methods] We measured internal rotation with the shoulder in extension in 26 healthy adults (average age, 25.2 ± 2.5 years). Internal rotation was measured passively in the supine position at 30° of shoulder extension. Additionally, a hand-behind-back motion was performed, and the hand-behind-back distance was measured. The relationship between the angle of internal rotation with the shoulder in extension and hand-behind-back distance was evaluated using Pearson's product-moment correlation. The level of significance was set at 5%. [Results] The angle of internal rotation with the shoulder in extension and the hand-behind-back distance correlate significantly. [Conclusion] Internal rotation with the shoulder in extension is a good indicator of hand-behind-back motion.

Excitability of anterior horn cells after periodic or discrete repetitive movements.

INTRODUCTION/AIMS: It has been well established that spasticity interferes with smooth joint movements. Although the degree of spasticity is related to the excitability of anterior horn cells and is thought to improve after repetitive movements, the effect of the rhythm of repetitive movements on the excitability of anterior horn cells remains unknown. Therefore, we investigated the excitability of anterior horn cells after periodic and discrete repetitive movements using F waves. METHODS: Right-handed, healthy subjects were recruited for this study. Subjects then performed periodic or discrete repetitive thumb abduction movements for 10 seconds, measuring the F waves before, immediately after, and then 2 and 4 minutes after performing these movements. Specifically, the F waves were recorded from the abductor pollicis brevis muscle, after median nerve stimulation at the wrist. Next, the F/M amplitude ratio, which was used to evaluate the excitability of anterior horn cells, was compared before, immediately after, and 2 and 4 minutes after each task. RESULTS: A total of 12 subjects participated in this study. In the periodic task, the F/M amplitude ratio was found to be significantly decreased immediately after the task compared with before the task, but there was no significant difference between the other trials. Conversely, in the discrete task, there was no significant difference in the F/M amplitude ratio between trials. DISCUSSION: Periodic repetitive movements were found to temporarily reduce the excitability of anterior horn cells.

Treatment patterns in pancreatic cancer patients based on a hospital claims database in Japan.

BACKGROUND: Pancreatic cancer treatment is evolving, but few studies have examined a nationwide trend in the treatment patterns. The purpose of this study was to clarify real-world treatment patterns for pancreatic cancer in Japan. METHODS: This retrospective study examined the treatment patterns among 68 479 patients, who had pancreatic cancer diagnosis in Medical Data Vision claims database from 2010 to 2018. We extracted relevant data on treatment options, including chemotherapy, surgery and their combination. For patients who had undergone chemotherapy, we sought to analyse the use of different chemotherapy regimens. In addition, we examined the trend in treatment patterns by age group (<59, 60-69, 70-79, ≥80). RESULTS: The trend in treatment options of pancreatic cancer remained stable from 2010 to 2018, with chemotherapy being the most common therapeutic option and surgery performed in approximately half that of chemotherapy. On the other hand, the use of chemotherapy regimen had changed during the same period. Although gemcitabine was the most commonly administrated single-agent regimen in 2010, gemcitabine + nab-paclitaxel was the most frequently used therapeutic agent in 2018. In the older age groups (age ≥80), the majority of patients was untreated (supposedly received supportive care), and the use of conventional regimens such as gemcitabine or S-1 was common among those undergoing chemotherapy. CONCLUSIONS: Although chemotherapy has been the main treatment option for pancreatic cancer, the regimens of choice have increased significantly during the last decade. With accumulating evidence on combination chemotherapy, treatment options may further evolve in the future.

Effects of trunk anterior tilt and knee joint flexion angle changes on muscle activity in the lower limb muscles.

[Purpose] We examined the effects of trunk anterior tilt angle (TA) and knee flexion angle (KA) on lower limb muscle activity. [Participants and Methods] Twenty-eight healthy male participants (age, 24.7 ± 4.7 years) performed nine standing tasks with different TA and KA. The participants were instructed to remain still during each task. The nine standing tasks were randomly performed while measurements of muscle activity were obtained for seven muscles: gluteus maximus (GMAX), medial hamstrings (MH), lateral hamstrings (LH), rectus femoris (RF), vastus lateralis (VL), medial gastrocnemius (MG), and soleus (SOL). The activities of these muscles were normalized using isometric grade 3 of the manual muscle testing (isoMMT3). The intra-rater reliability for the mean values of the muscle activities measured with the isoMMT3 (intra-class correlation coefficient with 95% confidence interval) was confirmed using equation ICC (1,3). [Results] GMAX, MH, LH, RF, and MG were affected by both TA and KA, whereas VL was affected by KA, and SOL was affected by TA. [Conclusion] Our findings may facilitate a better understanding of the changes in muscle activity of the lower limb muscles due to differences in TA and KA.

Motor imagery while viewing self-finger movements facilitates the excitability of spinal motor neurons.

Action observation (AO) and motor imagery (MI) are potential methods to improve various motor functions. AO and MI facilitate corticospinal excitability. Additionally, the combination of AO and MI (AO + MI) facilitates greater corticospinal excitability than AO alone. However, it is unclear whether AO + MI facilitates the excitability of spinal motor neurons better than AO alone. Thus, in this study, we compared the excitability of spinal motor neurons between AO + MI and AO conditions using F-waves. We recruited healthy adult volunteers (n = 31) for F-wave analysis. We recorded F-waves during relaxation to determine the baseline level (Rest), followed by measurement during AO and AO + MI. To counterbalance the order effect, 15 participants performed AO first, while the others performed AO + MI first. F-wave persistence was significantly increased during AO and AO + MI compared to Rest. The F-wave/M-wave amplitude ratio was significantly increased during AO + MI compared to Rest. The present results suggest that the combination of AO and MI facilitates the excitability of spinal motor neurons compared to Rest, whereas AO alone does not.

Reaction of Oxygen with the Singlet Excited State of [n]Cycloparaphenylenes (n = 9, 12, and 15): A Time-Resolved Transient Absorption Study Seamlessly Covering Time Ranges from Subnanoseconds to Microseconds by the Randomly-Interleaved-Pulse-Train Method.

Reaction of 3O2 with singlet excited state (S1) of highly luminescent cycloparaphenylenes (CPPs), i.e., [n]CPP where n = 9, 12, and 15 in solution has been studied by transient absorption (TA) measurements seamless for the time range from subnanosecond to microsecond based on the randomly-interleaved-pulse-train (RIPT) method recently developed by our group. We found efficient quenching of S1 by 3O2 through observation of Sn ← S1 transient absorption and the steady state fluorescence measurements. Concomitantly, we have become aware of the acceleration of the rate of intersystem crossing (ISC) from S1 to the triplet excited state (T1) through the observation of the evident enhancement of Tn ← T1 absorption intensity. We have established the analysis procedure to evaluate the rate constant of ISC (kISC0) in the absence of O2 and the bimolecular rate constant of ISC induced by 3O2 (kISCO2) only by using TA decay data in the presence of O2. On the basis of these analyses, we further succeeded in determining the quantum yield of T1 (ΦT) with and without O2. In addition, the absorption coefficient of T1 (εT1) and S1 (εS1) could be estimated with reference to that of T1 of C60. These photophysical parameters are largely dependent on the ring size, where the lifetime of S1 (τS) in the absence and presence of O2 dominates ΦT as well as the quantum yield of fluorescence (ΦF).

Relationship between chronic ankle sprain instability and ultrasonographic evaluation of the peroneus during a single-leg standing task.

[Purpose] This study aimed to examine the relationship between chronic ankle sprain instability and ultrasonography of the peroneus muscles during a single-leg standing task. [Participants and Methods] We examined nine college-aged students with a history of lateral ankle joint sprain with chronic ankle sprain instability scores less than 24. Participants underwent ultrasonographic measurement of the pennation angle and muscle thickness of the peroneal and gastrocnemius muscle groups of both legs. In addition, participants were evaluated for fluctuation by the root mean square calculated from accelerations in the anteroposterior, lateral-horizontal, and vertical directions during the single-leg standing position by affixing the accelerometer to their waist. Measurement results were compared between sprain and non-sprain sides. [Results] Ultrasonography revealed a significant reduction in the feathered pennation angle of the long peroneal muscle on the side of the sprain, but no other significant differences. Also, significant extension was observed on the side of the sprain in the anteroposterior and vertical directions during single-leg standing; however, no significant differences were found in the lateral-horizontal direction. [Conclusion] Participants with chronic ankle sprain instability exhibited greater fluctuation in the anteroposterior and vertical directions. Such fluctuations are believed to be compensatory in nature because the feathered horn of the long peroneal muscle is decreased, and pronation of the forefoot is difficult during one-leg standing.

Robotic transanal minimally invasive surgery (TAMIS) with the newest robotic surgical platform: a multi-institutional North American experience.

BACKGROUND: Transanal minimally invasive surgery (TAMIS) offers intra-luminal full-thickness excision of rectal neoplasia. Robotic TAMIS (RT) allows for greater versatility in motion while operating in the limited space of the rectum. We present our experience with this technique in practice using the DaVinci Xi™ platform. METHOD: This is a multi-institutional retrospective analysis for patient undergoing Robotic TAMIS for resection of rectal lesions at two tertiary referral hospitals in the United States. Morbidity, mortality, anatomic measurement, and final pathology were analyzed. RESULTS: Thirty-four patients planned for Robotic TAMIS were identified. Average follow-up was 188 days. The average BMI was 29.5 ± 5.9. All patients had an American Society of Anesthesiologist (ASA) Class of 2 or greater and 21 (62%) were ASA 3 or greater. Rectal lesions located from 2 to 15 cm from the dentate line were successfully resected. Lesions up to 4.5 cm in the longest dimension were successfully resected. The average operative time was 100 ± 70 min, which correlated to a robotic console time of 76 ± 67 min. Patients were placed in Lithotomy in 32 (94%) cases and were prone in only 2 (6%) cases. There were no intraoperative complications or conversions to another technique. The only postoperative complication was a medically managed Clostridium difficile infection in 1 patient. Three patients were upstaged to T2 on final pathology and underwent successful formal resections. BMI was a statistically significant predictor of a longer operation. CONCLUSIONS: With increased reach and operative range of motion, Robotic TAMIS is a safe and effective method for excising low-risk rectal neoplasia with a wide range of anatomical measurements. Higher BMI is a significant predictor of a longer and likely more challenging operation.

An ERAS protocol for bariatric surgery: is it safe to discharge on post-operative day 1?

BACKGROUND: Laparoscopic sleeve gastrectomy is the most commonly performed bariatric surgery in the world. Enhanced recovery after surgery (ERAS) protocols have been shown to reduce complications and decrease length of stay for various types of surgeries. In this study, we propose an ERAS protocol for laparoscopic sleeve gastrectomy and compare the clinical outcomes with patients who received standard care. METHODS: We performed a single-institution retrospective analysis in patients who underwent laparoscopic sleeve gastrectomy from February 2015 to December 2017. Patients were stratified into standard care and ERAS protocol groups. The ERAS protocol consisted of goal-directed patient education, specific pre- and post-op multi-modal medication regimen, early ambulation, and early oral intake. Patients were discharged on their first post-operative day if they met appropriate post-surgical milestones. The primary outcomes were length of stay, 7- and 30-day readmission rates, and complication rates. Secondary outcomes included anti-emetic and pain medication utilization, post-operative emesis episodes per day, post-operative pain scores, and mortality. RESULTS: We included 214 consecutive patients who underwent sleeve gastrectomy, 130 were in the ERAS group and 84 were in the standard care group. Median hospital stay was significantly shorter in the ERAS group compared to the standard care group (1 vs. 2 days; p < 0.001). There were no differences in 7- or 30-day readmission rates (1.5 vs. 1.2%; p = 0.838, 2.3 vs. 2.4%; p = 0.966) or post-operative complications (6.2 vs. 3.6%; p = 0.410). The ERAS group also had decreased median intra-operative opioid consumption and self-reported pain scores on post-operative day 1 (27.5 MME vs. 27.4 MME; p = 0.044, 3.3 vs. 3.9; p = 0.046). Mortality rate was 0% overall. CONCLUSION: A cost-effective ERAS protocol for laparoscopic sleeve gastrectomy results in shorter length of stay, without increase in peri-operative morbidity or readmission rates.

Feedback protocol of 'fading knowledge of results' is effective for prolonging motor learning retention.

[Purpose] "Knowledge of results" (KR) is information about the success of an action relative to a goal. A reduced frequency of "knowledge of results" reportedly promotes motor learning more than a high frequency. However, the effect of gradually diminishing or increasing "knowledge of results" pattern has been rarely studied and is controversial. We investigated the effectiveness of diminishing "knowledge of results" pattern in motor learning. [Participants and Methods] Forty-six healthy adults were randomly assigned to either the 100% KR, 50% KR, or faded KR group. Participants were tasked with exerting 60% of their maximum voluntary contraction of their left shoulder flexion muscle in an isometric exercise. Participants practiced the task 20 times a day for 4 days. A pretest and posttest were conducted before and immediately after the acquisition, respectively. Retention tests were conducted 1 day, 1 week, and 2 weeks after the acquisition. [Results] The absolute error was significantly reduced in the posttest in the faded KR and 50% KR cohorts. However, there was no significant difference in the 100% KR group. In the faded KR subjects, the improvement effect was observed up to 1 week following acquisition. [Conclusion] Faded "knowledge of results" productively prolongs the effect of motor learning.

How bariatric surgery affects liver volume and fat density in NAFLD patients.

INTRODUCTION: Nonalcoholic fatty liver disease (NAFLD) is an epidemic in the obese population. Bariatric surgery is known to reverse multiple metabolic complications of obesity such as diabetes, dyslipidemia, and NAFLD, but the timing of liver changes has not been well described. MATERIALS AND METHODS: This was an IRB-approved, two-institutional prospective study. Bariatric patients received MRIs at baseline and after a pre-operative liquid diet. Liver biopsies were performed during surgery and if NAFLD positive, the patients received MRIs at 1, 3, and 6 months. Liver volumes and proton-density fat fraction (PDFF) were calculated from offline MRI images. Primary outcomes were changes in weight, body mass index (BMI), percent excess weight loss (EWL%), liver volume, and PDFF. Resolution of steatosis, as defined as PDFF < 6.4% based on previously published cutoffs, was assessed. Secondarily, outcomes were compared between patients who underwent laparoscopic sleeve gastrectomy (LSG) versus laparoscopic Roux-en-Y gastric bypass (LRYGB). RESULTS: From October 2010 to June 2015, 124 patients were recruited. 49 patients (39.5%) completed all five scans. EWL% at 6 months was 55.6 ± 19.0%. BMI decreased from 45.3 ± 5.9 to 34.4 ± 5.1 kg/m2 and mean liver volume decreased from 2464.6 ± 619.4 to 1874.3 ± 387.8 cm3 with a volume change of 21.4 ± 11.4%. PDFF decreased from 16.6 ± 7.8 to 4.4 ± 3.4%. At 6 months, 83.7% patients had resolution of steatosis. Liver volume plateaued at 1 month, but PDFF and BMI continued to decrease. There were no statistically significant differences in liver volume or PDFF reduction from baseline to 6 months between the LSG versus LRYGB subgroups. CONCLUSION: Patients with NAFLD undergoing bariatric surgery can expect significant decreases in liver volume and hepatic steatosis at 6 months, with 83.7% of patients achieving resolution of steatosis. Liver volume reduction plateaus 1-month post-bariatric surgery, but PDFF continues to decrease. LSG and LRYGB did not differ in efficacy for inducing regression of hepatosteatosis.