Medicare Reimbursement in Hand and Upper Extremity Procedures: A 20-Year Analysis.

PURPOSE: Concern exists that Medicare physician fees for procedures have decreased over the past 20 years. The Centers for Medicare & Medicaid Services (CMS) is set to re-evaluate these physician fees in the near future for concern that these procedures are overvalued. Our study sought to analyze trends in Medicare reimbursement rates from 2000 to 2019 for the top 20 most billed hand and upper extremity surgical procedures at our institution. METHODS: The financial database of a single academic tertiary care center was queried to identify the Current Procedural Terminology codes most frequently utilized in orthopedic hand and upper extremity procedures in 2019. The Physician Fee Schedule Look-Up Tool from the CMS was queried for annual physician fee data. Monetary data were adjusted for inflation using the consumer price index of Urban Research Series (CPI-U-RS) and expressed in 2019 constant US dollars (USD). The average annual and total percent change in reimbursement were calculated via linear regression for all procedures (P < .05). RESULTS: Accounting for inflation, the total average physician reimbursement decreased by 20.9% from 2000 to 2019, with 12 of 20 codes decreasing by more than 20%. The greatest decrease pertained to arthrodesis of the wrist at 33.9%. Upon linear regression, all procedures were found to decrease annually, with arthrodesis of the wrist decreasing by an average of 2.3% annually over this period. CONCLUSIONS: Over the past 2 decades, physician reimbursement for hand and upper extremity procedures has significantly decreased.

Race, Gender, and Primary Language Were Not Associated With Changes in Opioid Prescribing in Children: Results From a Single Institution, 2010 to 2020.

BACKGROUND: Patients should be prescribed medication based on their medical condition, without prejudice because of their race, gender, or primary language. However, previous research has shown that men are prescribed more medication than women, patients who are White are prescribed more medications than patients who are non-White, and English-speaking people are prescribed more medications than non-English-speaking patients. However, it is unclear whether these differences also occur in pediatric orthopaedic populations. QUESTIONS/PURPOSES: We asked: (1) Was the amount of opiates prescribed at discharge associated with patient age, gender, race, or primary language? (2) Did the amount of opiates prescribed to patients at discharge change from 2010 to 2020? METHODS: In a single center, between January 2010 and December 2019, we treated 331 patients younger than 18 years surgically for upper and lower long-bone extremity fractures. Patients were considered eligible if they had a nonpathologic fracture. Femur fractures were not included. Based on these criteria, all patients were eligible. The mean age was 12 ± 4 years. The mean weight was 57 ± 33 kg. Among these patients, 76% (253 of 331) were boys and 24% (78 of 331) were girls. From the hospital discharge records, we recorded the amount of opiates prescribed at the time of discharge as measured by morphine milligram equivalents (MMEs). We examined the association of age, gender, race, primary language, weight, and year of treatment using this measurement. We determined a patient's race retrospectively by information given by their parents at time of admission. We did not attempt to contact patients to obtain more nuanced information about their racial background. These data were obtained from the electronic health record. The Wilcoxon rank sum test, t-test, or chi-square test was used to assess associations depending on the distribution of variables, as appropriate. Because opioids as measured in MMEs is zero-inflated, a two-part model analysis was used to adjust for confounding variables. One component of the model was for the probability of having any opiate prescription and another was for the mean number of opioids received. Findings were considered statistically significant if p values were < 0.05. RESULTS: In total, 57% (189 of 331) of children were prescribed opiates at discharge after surgery for long-bone fractures. Opiate MMEs increased with patient age (r = 0.38; p < 0.01). Boys and girls showed no difference in the amounts of pain medication (adjusted odds ratio [OR] 1.38 [95% confidence interval (CI) 0.80 to 2.39]; p = 0.71; adjusted opioid difference: 0.35 MME [95% CI -51.7 to 52.4]; p = 0.99), nor were there differences between patients who were White and those who were non-White (adjusted OR 0.78 [95% CI 0.49 to 1.23]; p = 0.28; adjusted opioid difference: 21.5 MME [95% CI -19.3 to 62.4]; p = 0.30), or between patients for whom English was there primary language and those for whom English was not their primary language (adjusted OR 1.16 [95% CI 0.52 to 2.57]; p = 0.71; adjusted opioid difference: 22.7 MME [95% CI -55.7 to 101.3]; p = 0.57) when adjusted for age and weight. There was no change in opioid prescription amounts from 2010 to 2020 after adjusting for changes in patient age across years (Spearman r = -0.08; p = 0.16). CONCLUSION: Fairness in opioid prescribing based on race, gender, or primary language is possible. Additional research is needed to determine what factors in our institution led to this result. We suggest that prescribers should apply consistent protocols based on factors such as weight or injury type rather than making individual decisions for each patient. This will lead to fairer opioid prescribing to patients from different race and gender groups. LEVEL OF EVIDENCE: Level III, therapeutic study.

A Virtual Curriculum to Prepare Medical Students to Achieve Accreditation Council for Graduate Medical Education Level-1 Milestones in Orthopaedic Surgery.

As a part of the American healthcare system's response to the Coronavirus Disease 2019 (COVID-19) global pandemic, the Association of American Medical Colleges recommended that medical schools temporarily remove students from clinical settings and transition to an entirely online learning environment. This posed an unprecedented challenge to students in the clinical years of their medical education. To address this unexpected shift, we modified an in-person workshop to teach orthopaedic trauma basics to 5-week virtual course for third year medical students from several schools in New Jersey and Pennsylvania. We focused on moving students toward the Level-1 milestones for basic fracture care with a combination of weekly lectures and virtual interactive small group sessions, all conducted via WebEx and proctored by an orthopaedic attending or resident. The course was well received by students. Participation in the course was completely voluntary and did not count for credit at any institution. The course was valuable to students because the students who registered chose to fully complete the 5-week course and no student missed more than one small group session. On a postcourse survey, 100% of students said they would be highly likely to recommend the course to a future student, and the average rating for educational value of the course was 4.98 of 5. Given the current limitations in clinical education because of the COVID-19 pandemic, our course provides a reasonable alternative to clinical experience and prepares students with the knowledge and many of the skills that are required to succeed as orthopaedic interns. Furthermore, the success of our course this year suggests that similar programing may be a useful adjunct to clinical experiences even when it is safe to return to more traditional medical school scheduling.

Racial Diversity in Orthopedic Surgery.

Data from the US Census Bureau, the Accreditation Council for Graduate Medical Education, and the American Academy of Orthopaedic Surgeons reveal that orthopedic surgery is the least diverse of any surgical specialty and that diversity within orthopedics is not improving. Considerable data from both medicine and business suggest that improving diversity within the orthopedic surgery specialty would be of significant benefit to the orthopedic surgery profession and to patients. Multiple avenues for increasing diversity exist, including large-scale pipeline programs as well as personal and institutional efforts examining biases and decision-making processes.

The Effects of Age on the Outcomes of Elbow Release in Arthrogryposis.

PURPOSE: The goal of this study was to observe the effects of posterior elbow release on children with arthrogryposis at various age points: before the age of 2, between the ages of 2 and 3, and after the age of 3. METHODS: This study was a retrospective chart review of patients with arthrogryposis who underwent a posterior elbow release for an elbow extension contracture between 2007 and 2014 at one institution. Eighteen procedures in 13 patients, who had a minimum follow-up of at least 2 years, were included in the study. Patients were divided into 3 groups based on their age at the time of surgery: <2 years old, 2-3 years old, and >3 years old. Comparisons of the pre- and postoperative passive arcs of motion were made. RESULTS: The average preoperative arc of motion was 16° (0° to 30°) for the children younger than 2, 33.5° (5° to 60°) for the children 2-3, and 45° (25° to 80°) for the children older than 3. The average postoperative arc of motion was 88.2° (70° to 103°), 60° (15° to 85°), and 54.33° (23° to 70°) for the respective age groups. There was a clinically important difference in the postoperative arc of motion between the children less than 2 years old and both the children 2-3 years old and older than 3 years. CONCLUSIONS: This study demonstrates that children who underwent posterior elbow release before the age of 2 had a clinically important increase in their postoperative flexion and overall passive arc of elbow motion compared with older children at medium-term follow-up. The data suggest that earlier release may be better at restoring total passive arc of elbow motion. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Infant brain responses to felt and observed touch of hands and feet: an MEG study.

There is growing interest concerning the ways in which the human body, both one's own and that of others, is represented in the developing human brain. In two experiments with 7-month-old infants, we employed advances in infant magnetoencephalography (MEG) brain imaging to address novel questions concerning body representations in early development. Experiment 1 evaluated the spatiotemporal organization of infants' brain responses to being touched. A punctate touch to infants' hands and feet produced significant activation in the hand and foot areas of contralateral primary somatosensory cortex as well as in other parietal and frontal areas. Experiment 2 explored infant brain responses to visually perceiving another person's hand or foot being touched. Results showed significant activation in early visual regions and also in regions thought to be involved in multisensory body and self-other processing. Furthermore, observed touch of the hand and foot activated the infant's own primary somatosensory cortex, although less consistently than felt touch. These findings shed light on aspects of early social cognition, including action imitation, which may build, at least in part, on infant neural representations that map equivalences between the bodies of self and other.

Combined Elbow Release and Humeral Rotational Osteotomy in Arthrogryposis.

PURPOSE: The purpose of this study was to determine if a simultaneous posterior elbow release and humeral osteotomy to correct both the elbow extension contracture and the humeral internal rotation contracture in children with arthrogryposis can produce similar results as a posterior elbow release alone. METHODS: This study was a retrospective chart review of consecutive patients with arthrogryposis treated surgically for elbow extension contracture between 2007 and 2014. A total of 43 procedures in 36 patients had adequate available follow-up data and were included in the study. The postoperative range of motion reported was measured at the early follow-up (3-6 months), midterm follow-up (between 1 and 2 years), and the most recent long-term follow-up (after 2 years) from the date of surgery. Patients were grouped into 2 groups (simultaneous and release) based on the necessity of performing an ipsilateral humeral rotation osteotomy at the time of the release. RESULTS: At early follow-up, patients in both groups increased their total arc of motion. There was a significant difference in extension and arc of motion at midterm follow-up (between 1 and 2 years) between the simultaneous and the release groups with the simultaneous group significantly losing both terminal extension and total arc of motion. At more than 2 years follow-up, there remained a statistically significant difference in arc of motion, with the release group having a significantly larger arc of motion. Patients who underwent dual plating had a much larger arc of motion at early follow-up than the K-wire or single-plate fixation group, despite having similar preoperative extension, flexion, and arc of motion. This difference was also significant at late follow-up. CONCLUSIONS: Patients with posterior release alone had significantly greater improvement in total arc of motion and significantly better elbow extension than patients who underwent a simultaneous humeral osteotomy. However, rigid fixation with early mobilization may yield results comparable with the release alone group. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Does a Weekly Didactic Conference Improve Resident Performance on the Pediatric Domain of the Orthopaedic In-Training Examination?

BACKGROUND: Performance on the Orthopaedic In-training Examination (OITE) has been correlated with performance on the written portion of the American Board of Orthopaedic Surgery examination. Herein we sought to discover whether adding a regular pediatric didactic lecture improved residents' performance on the OITE's pediatric domain. METHODS: In 2012, a didactic lecture series was started in the University of Pittsburgh Medical Center (UPMC) Hamot Orthopaedic Residency Program (Hamot). This includes all topics in pediatric orthopaedic surgery and has teaching faculty present, and occurs weekly with all residents attending. A neighboring program [UMPC Pittsburgh (Pitt)] shares in these conferences, but only during their pediatric rotation. We sought to determine the effectiveness of the conference by comparing the historic scores from each program on the pediatric domain of the OITE examination to scores after the institution of the conference, and by comparing the 2 programs' scores. RESULTS: Both programs demonstrated improvement in OITE scores. In 2008, the mean examination score was 19.6±4.3 (11.0 to 30.0), and the mean percentile was 57.7±12.6 (32.0 to 88.0); in 2014, the mean examination score was 23.5±4.2 (14.0 to 33.0) and the mean percentile was 67.1±12.1 (40.0 to 94.0). OITE scores and percentiles improved with post graduate year (P<0.0001). Compared with the preconference years, Hamot residents answered 3.99 more questions correctly (P<0.0001) and Pitt residents answered 2.93 more questions correctly (P<0.0001). Before the conference, site was not a predictor of OITE score (P=0.06) or percentile (P=0.08); there was no significant difference found between the mean scores per program. However, in the postconference years, site did predict OITE scores. Controlling for year in training, Hamot residents scored higher on the OITE (2.3 points higher, P=0.003) and had higher percentiles (0.07 higher, P=0.004) than Pitt residents during the postconference years. CONCLUSIONS: This study suggests that adding a didactic pediatric lecture improved residents' scores on the OITE and indirectly suggests that more frequent attendance is associated with better scores. LEVEL OF EVIDENCE: Level III-retrospective case-control study.

Speech discrimination in 11-month-old bilingual and monolingual infants: a magnetoencephalography study.

Language experience shapes infants' abilities to process speech sounds, with universal phonetic discrimination abilities narrowing in the second half of the first year. Brain measures reveal a corresponding change in neural discrimination as the infant brain becomes selectively sensitive to its native language(s). Whether and how bilingual experience alters the transition to native language specific phonetic discrimination is important both theoretically and from a practical standpoint. Using whole head magnetoencephalography (MEG), we examined brain responses to Spanish and English syllables in Spanish-English bilingual and English monolingual 11-month-old infants. Monolingual infants showed sensitivity to English, while bilingual infants were sensitive to both languages. Neural responses indicate that the dual sensitivity of the bilingual brain is achieved by a slower transition from acoustic to phonetic sound analysis, an adaptive and advantageous response to increased variability in language input. Bilingual neural responses extend into the prefrontal and orbitofrontal cortex, which may be related to their previously described bilingual advantage in executive function skills. A video abstract of this article can be viewed at: https://youtu.be/TAYhj-gekqw.

Digital Chondrolysis and Epiphysiolysis Associated With Snakebite: A Report of 2 Cases.

BACKGROUND: Here, we present 2 cases of the unusual sequelae of a venomous bite to the finger in children resulting in chondrolysis and physeal loss. There have been few isolated case reports documenting this phenomenon. Currently, there is no preventative treatment, and patients should be warned of this possible complication of envenomation. METHODS: Two patients with chondrolysis and physeal loss have been seen in our practice. RESULTS: Chondrolysis and epiphysiolysis occurred in 2 patients. One patient was treated with proximal interphalangeal joint fusion and one is being managed conservatively. CONCLUSION: The toxic action of snake venom may cause loss of the growth plate and chondrolysis in the pediatric hand. LEVEL OF EVIDENCE: Level IV.

A brief review of extensor tendon injuries specific to the pediatric patient.

Extensor tendon injuries in the pediatric population require careful evaluation and treatment. This article focuses on the differences in injury type and treatment of pediatric versus adult extensor tendon injuries. A detailed history and physical examination is crucial in the management of extensor tendon injuries of the young patient. Treatment of pediatric extensor tendon injuries depends largely on the site of injury. A majority of these injuries may be treated with splinting or primary repair. Treatment methods that require high compliance must be adjusted for the young child.

Complications related to harvest of the proximal end of the fibula: a systematic review.

BACKGROUND: The fibula is a common source of bone graft used in skeletal reconstruction. Although in most cases only the diaphysis of the fibula is used, there are clinical scenarios in which the proximal end of the fibula and fibular head are harvested for use in articular reconstruction. The purpose of this systematic review is to determine the incidence of knee instability and peroneal nerve motor dysfunction associated with removal of the proximal end of the fibula and fibular head. METHODS: A systematic search was performed using the PubMed, Ovid MEDLINE, and cochrane databases. Studies accepted for review included those that clearly reported donor site morbidity (instability or peroneal nerve motor dysfunction) after proximal fibula resection. All studies in which the proximal fibula was resected for bone graft or for marginal resection of tumor were included. RESULTS: Fifteen studies reporting a total of 337 patients were included. The rate of symptomatic knee instability after proximal fibula resection was 3.9%. The incidence of instability that was detectible on physical examination or stress radiographs was higher. Although transient motor dysfunction was not uncommon, the incidence of persistent peroneal nerve motor dysfunction was 2.6%. CONCLUSION: Although asymptomatic laxity is common, the incidence of symptomatic knee instability after resection of the proximal fibula is relatively low. The incidence of persistent peroneal nerve motor dysfunction is also low when the nerve is intentionally protected during surgery.

Infants' brain responses to speech suggest analysis by synthesis.

Historic theories of speech perception (Motor Theory and Analysis by Synthesis) invoked listeners' knowledge of speech production to explain speech perception. Neuroimaging data show that adult listeners activate motor brain areas during speech perception. In two experiments using magnetoencephalography (MEG), we investigated motor brain activation, as well as auditory brain activation, during discrimination of native and nonnative syllables in infants at two ages that straddle the developmental transition from language-universal to language-specific speech perception. Adults are also tested in Exp. 1. MEG data revealed that 7-mo-old infants activate auditory (superior temporal) as well as motor brain areas (Broca's area, cerebellum) in response to speech, and equivalently for native and nonnative syllables. However, in 11- and 12-mo-old infants, native speech activates auditory brain areas to a greater degree than nonnative, whereas nonnative speech activates motor brain areas to a greater degree than native speech. This double dissociation in 11- to 12-mo-old infants matches the pattern of results obtained in adult listeners. Our infant data are consistent with Analysis by Synthesis: auditory analysis of speech is coupled with synthesis of the motor plans necessary to produce the speech signal. The findings have implications for: (i) perception-action theories of speech perception, (ii) the impact of "motherese" on early language learning, and (iii) the "social-gating" hypothesis and humans' development of social understanding.

A line drawn along the radial shaft misses the capitellum in 16% of radiographs of normal elbows.

BACKGROUND: The radiocapitellar line (RCL) is a routinely referenced radiographic measurement for evaluating injury of the pediatric elbow, such as a Monteggia fracture. It is most commonly described as a line drawn along the radius that should intercept the center of the capitellum in a normal elbow. However, the RCL has not been rigorously defined or validated in young children. METHODS: The RCL was drawn out on the anteroposterior and lateral radiographs of 116 normal pediatric elbows by 3 examiners. On each radiograph, lines were drawn along the longitudinal center of the radial neck as well as the radial shaft. The distance from each of these lines to the center of the capitellum was defined as the line-capitellar distance (LCD). The LCD was standardized to the patient size and correlated with patient variables. RESULTS: Of the 2052 RCLs drawn, 50% (1029/2052) fell outside the middle third of the capitellum and 8.6% (176/2052) missed the capitellum completely. Lines drawn along the radial neck in the anteroposterior and lateral views missed the capitellum less frequently (1.2% vs. 12.7%, P<0.0001) and passed through its central third less (77.8% vs. 44.7%, P<0.0001) when compared with lines drawn using the radial shaft. Lines along the radial neck intersected the capitellum significantly more often on the lateral view than on the anteroposterior view (98.8% vs. 96.8%, P=0.06) and were more likely to pass through the center third of the capitellum (77.8% vs. 55.5%, P<0.0001). With both techniques of drawing the RCL, the percent of measurements falling within the middle third of the capitellum was higher in patients above 5 years of age (P<0.001). The RCL is more reliable in older patients and shows considerable variation in infants. CONCLUSIONS: The RCL does not invariably bisect or fall within the middle third of the capitellum in normal pediatric elbows. Therefore, an abnormal RCL is suggestive but not pathognomonic for injury such as Monteggia fracture. An RCL drawn along the radial shaft will miss the capitellum in 15.6% of elbows. The most consistent RCL is drawn along the radial neck on the lateral view. Patient variables such as age and sex should be considered in the ability of the RCL to identify elbow injury. LEVEL OF EVIDENCE: Diagnostic Level 3.

Prevention of Anterior Cruciate Ligament Rupture in Female Athletes: A Systematic Review.

BACKGROUND: A number of reports have been published on the effectiveness and design of intervention programs for the prevention of rupture of the anterior cruciate ligament (ACL) in female athletes. The purpose of this study was to systematically review the literature to determine the effectiveness of neuromuscular training programs in preventing ACL injury in female athletes. METHODS: A systematic review was performed with use of the PubMed, MEDLINE, Embase, and Cochrane Central Register of Controlled Trials databases. The search terms included "anterior cruciate ligament" and "ACL" combined with "prevention" and "intervention." The searches included material indexed by September 30, 2013. Data concerning study design, the characteristics of participants, the details of the neuromuscular programs, the types of sports, and number of ACL ruptures were extracted from the studies. Study heterogeneity was assessed with funnel plot and Egger regression methods. Pooled effects were calculated with use of a DerSimonian-Laird random-effects model. The number needed to treat was calculated on the basis of pooled incidence data. RESULTS: The risk of ACL rupture was 1.83 times higher for female athletes who did not participate in neuromuscular ACL-prevention training programs (odds ratio [OR], 1.83; 95% confidence interval [95% CI], 1.08 to 3.10; p = 0.02). In studies that focused exclusively on soccer, the risk of ACL rupture was 2.62 times higher for nonparticipating athletes (OR, 2.62; 95% CI, 1.59 to 4.32; p < 0.01). When the data were analyzed according to the timing of the intervention, no significant effects were found. In studies in which the program took place both preseason and in-season, the risk (odds ratio) of ACL rupture for nonparticipating athletes was 2.34 (95% CI, 0.82 to 6.7; p = 0.11). In studies in which the intervention took place in-season only, the risk (odds ratio) of ACL rupture for nonparticipating athletes was 1.25 (95% CI, 0.23 to 6.75; p = 0.8). The number needed to treat to prevent a single ACL rupture was 128.7 athletes. We found no significant heterogeneity among the included studies. The I value was 35.40% (p = 0.11). No significant publication bias was found in our included studies. CONCLUSIONS: The results of this systematic review and meta-analysis favor a protective effect of neuromuscular training programs on the risk of ACL rupture in female athletes. This protective effect is more pronounced in soccer players. Additional research is needed to design the optimal training program. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions to Authors for a complete description of levels of evidence.

Both bone forearm fractures in children and adolescents, which fixation strategy is superior - plates or nails? A systematic review and meta-analysis of observational studies.

OBJECTIVES: To determine which method of operative fixation, plate and screw, or intramedullary nails (IMN) fixation is superior for pediatric both bone forearm fractures (BBFF). DATA SOURCES: PubMed, EMBASE, and Cochrane, from 1980 to 2011, in English. STUDY SELECTION: We selected for detailed review all studies with children or adolescents with comparative data (or individual patient data) for BBFF fixed with IMN or open reduction internal fixation with plates and screws. Selected studies also required outcomes of interest including fracture union, complications, functional outcome, cosmesis, and the need for hardware removal. DATA EXTRACTION: Data were extracted from each study; publication bias was assessed using funnel plots and Egger statistic. Study quality was assessed using the standardized method described by Zaza et al. DATA SYNTHESIS: A DerSimonian and Laird random-effects model was used to assess differences between dichotomous variables. A continuity correction was applied in cases of zero events. A sensitivity analysis was performed with studies that separated out older children and adolescents. CONCLUSIONS: All studies identified were observational. IMN and plate and screw constructs are acceptable options in the fixation of pediatric BBFF. The literature fails to demonstrate a difference between IMN and plate and screw constructs. Outcomes were excellent in nearly 9 of 10 patients regardless of fixation strategy. Delayed unions and nonunions were rare and slightly more common in IMN, although the difference was not statistically significant. These results suggest that complication rates are similar, although the type of complication may vary. IMN provides improved cosmesis but, in general, requires a second operation to remove hardware.

Selection of appropriate treatment options for hand fractures.

Selecting the appropriate treatment method for hand fractures is challenging due to the wide spectrum of presentation and the enormous array of surgical and nonoperative treatment options. Unfortunately, the scientific evidence to help guide decision making is not of high quality. Because of this, the surgeon must rely on a few basic principles to guide treatment. This article provides an overview of the scientific evidence, and discusses the principles and rationale used to treat hand fractures.

Spectral signal space projection algorithm for frequency domain MEG and EEG denoising, whitening, and source imaging.

MEG and EEG data contain additive correlated noise generated by environmental and physiological sources. To suppress this type of spatially coloured noise, source estimation is often performed with spatial whitening based on a measured or estimated noise covariance matrix. However, artifacts that span relatively small noise subspaces, such as cardiac, ocular, and muscle artifacts, are often explicitly removed by a variety of denoising methods (e.g., signal space projection) before source imaging. Here, we introduce a new approach, the spectral signal space projection (S(3)P) algorithm, in which time-frequency (TF)-specific spatial projectors are designed and applied to the noisy TF-transformed data, and whitened source estimation is performed in the TF domain. The approach can be used to derive spectral variants of all linear time domain whitened source estimation algorithms. The denoised sensor and source time series are obtained by the corresponding inverse TF-transform. The method is evaluated and compared with existing subspace projection and signal separation techniques using experimental data. Altogether, S(3)P provides an expanded framework for MEG/EEG data denoising and whitened source imaging in both the time and frequency/scale domains.

Neuromagnetic source imaging of abnormal spontaneous activity in tinnitus patient modulated by electrical cortical stimulation.

Electrical cortical stimulation (CS) of the auditory cortices has been shown to reduce the severity of debilitating tinnitus in some patients. In this study, we performed MEG source imaging of spontaneous brain activity during concurrent CS of the left secondary auditory cortex of a volunteer suffering from right unilateral tinnitus. CS produced MEG artifacts which were successfully sorted and removed using a combination of sensor and source level signal separation and classification techniques. This contribution provides the first proof of concept reporting on analysis of MEG data with concurrent CS. Effects of CS on ongoing brain activity were revealed at the MEG sensor and source levels and indicate CS significantly reduced ongoing brain activity in the lower frequency range (<40Hz), and emphasized its higher (>40Hz), gamma range components. Further, our results show that CS increased the spectral correlation across multiple frequency bands in the low and high gamma ranges, and between the alpha and beta bands of the MEG. Finally, MEG sources localized in the auditory cortices and nearby regions exhibited abnormal spectral activity that was suppressed by CS. These results provide promising evidence in favor of the Thalamocortical Dysrhytmia (TCD) hypothesis of tinnitus, and suggest that CS may prove to be an effective treatment of tinnitus when targeted to brain regions exhibiting abnormal spontaneous activity.