Simulation of facial expressions using person-specific sEMG signals controlling a biomechanical face model

Purpose

Functional inoperability in advanced oral cancer is difficult to assess preoperatively. To assess functions of lips and tongue, biomechanical models are required. Apart from adjusting generic models to individual anatomy, muscle activation patterns (MAPs) driving patient-specific functional movements are necessary to predict remaining functional outcome. We aim to evaluate how volunteer-specific MAPs derived from surface electromyographic (sEMG) signals control a biomechanical face model.

Methods

Muscle activity of seven facial muscles in six volunteers was measured bilaterally with sEMG. A triple camera set-up recorded 3D lip movement. The generic face model in ArtiSynth was adapted to our needs. We controlled the model using the volunteer-specific MAPs. Three activation strategies were tested: activating all muscles \((\hbox {act}_\mathrm{all})\), selecting the three muscles showing highest muscle activity bilaterally \((\hbox {act}_3)\)—this was calculated by taking the mean of left and right muscles and then selecting the three with highest variance—and activating the muscles considered most relevant per instruction \((\hbox {act}_\mathrm{rel})\), bilaterally. The model’s lip movement was compared to the actual lip movement performed by the volunteers, using 3D correlation coefficients \((\rho )\).

Results

The correlation coefficient between simulations and measurements with \(\hbox {act}_\mathrm{rel}\) resulted in a median \(\rho \) of 0.77. \(\hbox {act}_3\) had a median \(\rho \) of 0.78, whereas with \(\hbox {act}_\mathrm{all}\) the median \(\rho \) decreased to 0.45.

Conclusion

We demonstrated that MAPs derived from noninvasive sEMG measurements can control movement of the lips in a generic finite element face model with a median \(\rho \) of 0.78. Ultimately, this is important to show the patient-specific residual movement using the patient’s own MAPs. When the required treatment tools and personalisation techniques for geometry and anatomy become available, this may enable surgeons to test the functional results of wedge excisions for lip cancer in a virtual environment and to weigh surgery versus organ-sparing radiotherapy or photodynamic therapy.

     

The effect of exercise training in symptomatic patients with grown-up congenital heart disease: a review

Introduction: The number of grown-up congenital heart disease (GUCH) patients is steadily increasing. Unfortunately, the majority of these patients suffer from late sequelae, with heart failure being the most common cause of death. Exercise training is beneficial and safe in patients with acquired heart failure, as well as in asymptomatic GUCH patients. However, its effect remains unknown in symptomatic GUCH patients. This could cause reticence on positive sports advice, with possible counterproductive effects.

Areas covered: A review of current literature was performed to evaluate the effect of exercise training in symptomatic (NYHA≥2) GUCH patients. The search yielded a mere three studies including symptomatic patients, and another six studies including also patients in NYHA 1 without making clear distinction between the NYHA subgroups.

Expert commentary: Suboptimal trial designs, low patient numbers, and homogeneity of investigated cardiac anomalies make this review insufficient to draw definite conclusions. However, all studies describe overall positive effects of exercise training in symptomatic GUCH patients in terms of exercise capacity and quality of life. There were no safety concerns. Larger-scaled, randomized controlled trials are needed to obtain certainty.     

Periprocedural embolic events related to carotid artery stenting detected by diffusion-weighted MRI: comparison between proximal and distal embolus protection devices.

PURPOSE: To evaluate and compare the efficacy of proximal versus distal embolus protection devices (EPD) during carotid artery angioplasty/stenting (CAS) based on diffusion-weighted magnetic resonance imaging (DW-MRI). METHODS: Forty-four patients (31 men; mean age 68 years, range 48-85) underwent protected CAS and had DW-MRI before and after the intervention. The cohort was analyzed according to the type of EPD used: a proximal EPD was deployed in 25 (56.8%) patients (17 men; mean age 66 years, range 48-85) and a distal filter in 19 (14 men; mean age 70 years, range 58-79). Fifteen (60.0%) patients with proximal protection were symptomatic of the target lesion; in the distal protection group, 10 (52.6%) were symptomatic. RESULTS: New lesions were seen on the postinterventional DW-MRI in 28.0% (7/25) of the proximal EPD group versus 32.6% (6/19) of those with a distal filter (p = NS). The majority were clinically silent. The new lesions in the vascular territory of the stented carotid artery in the group as a whole and per patient were fewer in the proximal EPD group (p = NS). No significant differences were noted in the T(2) appearance of the new lesions or the number of new lesions observed away from the vascular territory of the stented artery. CONCLUSION: Proximal embolus protection devices show a nonsignificant trend toward fewer embolic events, which warrants large-scale studies. Furthermore, proximal protection devices can be useful to control and treat acute in-stent thrombosis.     

Melatonin effects on sleep, mood, and cognition in elderly with mild cognitive impairment

Abstract: The effects of immediate-release melatonin on circadian rest-activity profiles, cognition, and mood were investigated in ten elderly individuals with self-reported sleep-wake disturbances. Melatonin (6 mg), administered 2 hr before habitual bedtime, enhanced the rest-activity rhythm and improved sleep quality as observed in a reduction in sleep onset latency and in the number of transitions from sleep to wakefulness. However, total sleep time was not significantly increased nor was wake within sleep significantly reduced. The ability to remember previously learned items improved along with a significant reduction in depressed moods. No side effects or contraindications were reported by any of our participants during the 10 day trials. These data suggest that melatonin can safely improve some aspects of sleep, memory, and mood in the elderly in short-term use.     

The efficacy and safety of low- and high-dose fixed combinations of irbesartan/hydrochlorothiazide in patients with uncontrolled systolic blood pressure on monotherapy: the INCLUSIVE trial

This multicenter, prospective, open-label, single-arm study determined the efficacy and safety of irbesartan/hydrochlorothiazide (HCTZ) fixed combinations in patients (n=1005), aged 18 years and older, with uncontrolled systolic blood pressure (SBP) of 140-159 mm Hg (130-159 mm Hg for type 2 diabetes mellitus) after at least 4 weeks of antihypertensive monotherapy. Treatment was sequential: placebo (4-5 weeks), HCTZ 12.5 mg (2 weeks), irbesartan/HCTZ 150/12.5 mg (8 weeks), and irbesartan/HCTZ 300/25 mg (8 weeks). Enrolled patients (n=844) were aged 57.3+/-11.2 years; 52% were women, 23% were African American, and 14% were Hispanic. Thirty percent had type 2 diabetes mellitus, 46% had metabolic syndrome, and baseline blood pressure was 154.0+/-10.3/91.3+/-8.8 mm Hg. The mean change in SBP from placebo end to the primary end point, Week 18 (intent-to-treat population, n=736) was -21.5+/-14.3 mm Hg (p<0.001). The mean change in diastolic blood pressure (DBP) was -10.4+/-8.7 mm Hg (p<0.001). The mean Week 18 SBP/DBP was 132.9+/-13.8/81.1+/-9.7 mm Hg. Overall, 77% (95% confidence interval, 74%-80%) of patients achieved SBP goal (<140 mm Hg; <130 mm Hg for type 2 diabetes mellitus); 83% (95% confidence interval, 80%-86%) achieved DBP goal (<90 mm Hg; <80 mm Hg for type 2 diabetes mellitus); and 69% (95% confidence interval, 66%-72%) achieved dual SBP/DBP goal. Treatments were well tolerated. This irbesartan/HCTZ treatment regimen achieved SBP goals in more than 75% of patients uncontrolled on monotherapy.     

Percutaneous transradial coronary palmaz-schatz stent implantation,guided by intravascular ultrasound

Intravascular ultrasound (IVUS) allows accurate assessment of stent deployment, its use being confined to the use of 8 French (F) guiding catheters. We evaluated the feasibility of combining transradial artery Palmaz-Schatz stent implantation through 6F guiding catheters with IVUS for assessment of stent diameter after delivery at moderate inflation pressures (10-12 atmospheres [atm]) with compliant balloons and after high pressure dilatations with balloons of intermediate compliance. In 8 consecutive patients, 12 stents were delivered with Scimed® Express^TM balloon catheters at 10-12 atm followed by IVUS (EndoSonics® CathScanner; Visions® FX 3.5F 20 MHz transducer). An ultrasound study was repeated after high pressure dilatations (16-20 atm) with Schneider® Magical Speedy^TM balloon catheters. The balloon diameters were derived from manufacturer provided specifications. In all patients the transducer could easily be advanced through the guiding catheters. Reference diameter of the stented segment was 3.7 ± 0.5 mm (2.7-4.5) and the diameter of Scimed® Express^TM balloons during inflation was 4.0 ± 0.3 mm (3.6-4.7). Stent diameter was 3.0 ± 0.1 mm (2.8-3.2) (P < 0.001 compared to the reference and the balloon diameter). The diameter of the Schneide® Magical Speedy^TM balloons at secondary dilatations with 16 ± 3 atm (14-20) was 4.1 ± 0.4 mm (3.3-4.5) (P = 0.50 compared to the initial balloon diameter). Final stent diameter was 3.3 ± 0.4 mm (2.9-4.1) (P = 0.02 compared to the initial stent diameter). All stents were symmetrically deployed and well apposed. No damage to vessel or stents was detected after passage of the transducer. Thus ultrasound guided stenting via 6F guiding catheters is feasible, and high pressure dilatations with balloons of intermediate compliance results in better stent expansion than after 10-12 atm inflations with compliant balloon catheters.     

Safety of long-term interruption of successful antiretroviral therapy: the ATHENA cohort study

We studied the dynamics of CD4 cell counts after the interruption of virologically successful highly active antiretroviral therapy (HAART) in 139 patients. Changes in CD4 cell counts during HAART interruption followed a biphasic pattern: an initial rapid decline during the first month followed by a slow decrease. During 48 weeks of follow-up mean CD4 cell counts remained just above the mean pre-HAART level. This limits the feasibility of structured treatment interruptions for patients with low nadir CD4 cell counts.     

Age-related changes in processing positive and negative feedback: Is there a positivity effect for older adults?

Older people sometimes show a bias toward the processing of positive information. In this study, we used an event-related potential approach to examine whether such a positivity bias is also present during feedback processing in older adults. Our results suggest that a fast initial monitoring process, as reflected in the feedback-related negativity (FRN), is sensitive to the expectancy of events irrespective of their valence for older (aged 70–77 years) as well as younger (aged 20–27 years) adults. In contrast, in a later evaluation process, associated with memory updating and indexed by the P300, both age groups preferably processed unexpected positive feedback. However, younger adults additionally differentiated between unexpected negative and expected feedback while older adults did not, probably due to a lower working memory capacity.     

Magnetic resonance spectroscopy with transcranial direct current stimulation to explore the underlying biochemical and physiological mechanism of the human brain: A systematic review

A large body of molecular and neurophysiological evidence connects synaptic plasticity to specific functions and energy metabolism in particular areas of the brain. Furthermore, altered plasticity and energy regulation has been associated with a number of neuropsychiatric disorders. A favourable approach enabling the modulation of neuronal excitability and energy in humans is to stimulate the brain using transcranial direct current stimulation (tDCS) and then to observe the effect on neurometabolites using magnetic resonance spectroscopy (MRS). In this way, a well‐defined modulation of brain energy and excitability can be achieved using a dedicated tDCS protocol to a predetermined brain region. This systematic review was guided by the preferred reporting items for systematic reviews and meta‐analysis and summarises recent literature studying the effect of tDCS on neurometabolites in the human brain as measured by proton or phosphorus MRS. Limitations and recommendations are discussed for future research. The findings of this review provide clear evidence for the potential of using tDCS and MRS to examine and understand the effect of neurometabolites in the in vivo human brain.