Generalizable Deep Learning-based Sleep Staging Approach for Ambulatory Textile Electrode Headband Recordings.

Reliable, automated, and user-friendly solutions for the identification of sleep stages in home environment are needed in various clinical and scientific research settings. Previously we have shown that signals recorded with an easily applicable textile electrode headband (FocusBand, T 2 Green Pty Ltd) contain characteristics similar to the standard electrooculography (EOG, E1-M2). We hypothesize that the electroencephalographic (EEG) signals recorded using the textile electrode headband are similar enough with standard EOG in order to develop an automatic neural network-based sleep staging method that generalizes from diagnostic polysomnographic (PSG) data to ambulatory sleep recordings of textile electrode-based forehead EEG. Standard EOG signals together with manually annotated sleep stages from clinical PSG dataset (n = 876) were used to train, validate, and test a fully convolutional neural network (CNN). Furthermore, ambulatory sleep recordings including a standard set of gel-based electrodes and the textile electrode headband were conducted for 10 healthy volunteers at their homes to test the generalizability of the model. In the test set (n = 88) of the clinical dataset, the model's accuracy for 5-stage sleep stage classification was 80% (κ = 0.73) using only the single-channel EOG. The model generalized well for the headband-data, reaching 82% (κ = 0.75) overall sleep staging accuracy. In comparison, accuracy of the model was 87% (κ = 0.82) in home recordings using the standard EOG. In conclusion, the CNN model shows potential on automatic sleep staging of healthy individuals using a reusable electrode headband in a home environment.

Associations between serum homocysteine, holotranscobalamin, folate and cognition in the elderly: a longitudinal study.

OBJECTIVES: To examine the associations between serum homocysteine (tHcy), holotranscobalamin (holoTC, the biologically active fraction of vitamin B12) and folate and cognitive functioning in a longitudinal population-based study of Finnish elderly subjects. SUBJECTS AND DESIGN: tHcy, holoTC and folate were measured at baseline in 274 dementia-free subjects aged 65-79years from the Cardiovascular Risk Factors, Aging and Dementia study. Subjects were re-examined 7years later, and global cognition, episodic memory, executive functioning, verbal expression and psychomotor speed were assessed. RESULTS: Higher baseline tHcy levels were associated with poorer performance in global cognition, relative difference: 0.90 [95% confidence interval (CI) 0.81-0.99]; episodic memory: 0.87 (95% CI 0.77-0.99); executive functions: 0.86 (95% CI 0.75-0.98); and verbal expression: 0.89 (95% CI 0.81-0.97) at follow-up. Increased holoTC levels were related to better performance on global cognition: 1.09 (95% CI 1.00-1.19); executive functions: 1.11 (95% CI 1.01-1.21); and psychomotor speed: 1.13 (95% CI 1.01-1.26). After excluding 20 cases of incident dementia, increased tHcy remained associated with poorer performance in episodic memory, execution functions and verbal expression. Higher holoTC levels tended to be related to better performance in executive functions and psychomotor speed, while elevated serum folate concentrations were significantly related to higher scores in global cognition and verbal expression tests. CONCLUSIONS: tHcy, holoTC and folate levels are related to cognitive performance 7years later even in nondemented elderly subjects. Randomized trials are needed to determine the impact of vitamin B12 and folate supplementation on preventing cognitive decline in the elderly.

Homocysteine and holotranscobalamin and the risk of Alzheimer disease: a longitudinal study.

OBJECTIVE: To examine the relation between serum levels of homocysteine (tHcy) and holotranscobalamin (holoTC), the active fraction of vitamin B12, and risk of incident Alzheimer disease (AD) in a sample of Finnish community-dwelling elderly. METHODS: A dementia-free sample of 271 subjects aged 65-79 years derived from the Cardiovascular Risk Factors, Aging, and Dementia (CAIDE) study was followed up for 7 years to detect incident AD. The association between serum tHcy and holoTC with AD was analyzed with multiple logistic regression after adjusting for several potential confounders, including common vascular risk factors. RESULTS: The odds ratios (ORs) (95% confidence interval [CI]) for AD were 1.16 (1.04-1.31) per increase of 1 µmol/L of tHcy at baseline and 0.980 (0.965-0.995) for each increase of 1 pmol/L baseline holoTC. Adjustment for several potential confounders including age, sex, education, APOE ε4 allele, body mass index, Mini-Mental State Examination, smoking, stroke, and blood pressure did not alter the associations: ORs (95% CI) for AD became 1.19 (1.01-1.39) for tHcy and 0.977 (0.958-0.997) for holoTC. Adjusting for holoTC attenuated the tHcy-AD link (OR changed from 1.16 to 1.10, 95% CI 0.96-1.25). The holoTC-AD relationship was less influenced by controlling for tHcy (OR changed from 0.980 to 0.984, 95% CI 0.968-1.000). Addition of folate did not change any of the results. CONCLUSIONS: This study suggests that both tHcy and holoTC may be involved in the development of AD. The tHcy-AD link may be partly explained by serum holoTC. The role of holoTC in AD should be further investigated.

Midlife smoking, apolipoprotein E and risk of dementia and Alzheimer's disease: a population-based cardiovascular risk factors, aging and dementia study.

AIM: To elucidate the effect of midlife smoking on the risk of dementia and Alzheimer's disease (AD), and the possible modification of this relation by the apolipoprotein E (APOE) ε4. METHODS: Participants of the Cardiovascular Risk Factors, Aging and Dementia study were randomly selected from population-based samples originally studied in midlife (1972, 1977, 1982 or 1988). After an average follow-up of 21 years, 1,449 persons (73%) aged 65-79 years took part in a reexamination in 1998. RESULTS: Smoking in midlife increased the risk of dementia (odds ratio, OR: 4.93; 95% CI: 1.51-16.11) and AD (OR: 6.56; 95% CI: 1.80-23.94) among the APOE ε4 carriers, but not among the APOE ε4 noncarriers. CONCLUSION: Midlife smoking was associated with an increased risk of dementia and AD later in life only among those individuals carrying the APOE ε4 allele. These results suggest that the association between smoking and AD may be complex and vary according to genotype.

Genetic variability of fragmented stands of pedunculate oak (Quercus robur) in Finland.

The genetic structure of 33 natural Quercus robur stands in Finland was studied using 13 allozyme loci to analyze the effects of fragmentation in a wind-pollinated tree species. The present fragmented and discontinuous distribution of oak is a result of both short-term human impact and long-term climatic and geological change, including post-glacial land uplift. In accordance with general expectations, genetic diversity in small populations was lower than that in large populations, and differentiation among small populations was higher than that among large populations. Heterozygote deficiency was more pronounced in large populations, which is proposed to be a Wahlund effect created by either spatial sub-structuring or the existence of synchronized flowering lineages. Also genetic differentiation was higher and diversity lower in Finland than the estimates reported for Central Europe. There were differences in the genetic structure on sites of different geological age. We suggest that on most geologically old sites drift has a prominent effect whereas on younger sites also founder effects may be important.

Submonolayer growth with anomalously high island density in hyperthermal deposition.

We present a rate equation model for submonolayer island growth under conditions where hyperthermal deposition techniques such as low-energy ion deposition are employed to achieve smooth layer-by-layer growth. By asymptotic analysis, we demonstrate that the model exhibits stationary behavior with well-defined dynamic and growth exponents beta and chi, respectively, in the limit of small and high detachment rates. We verify these predictions by using the particle coalescence simulation method. The simulations reveal the existence of a relatively sharp transition regime with an increasing detachment rate of adatoms from high values of the growth exponent beta approximately 1 to much smaller values of beta determined by detachment and island diffusion processes. Our numerical results for the island size distribution indicate an anomalously high number of small islands, in agreement with available experimental data.

Instability and wavelength selection during step flow growth of metal surfaces vicinal to fcc(001).

We study the onset and development of ledge instabilities during growth of vicinal metal surfaces using kinetic Monte Carlo simulations. We observe the formation of periodic patterns at [110] close packed step edges on surfaces vicinal to fcc(001) under realistic molecular beam epitaxy conditions. The corresponding wavelength and its temperature dependence are studied in detail. Simulations suggest that the ledge instability on fcc(1,1,m) vicinal surfaces is controlled by the strong kink Ehrlich-Schwoebel barrier, with the wavelength determined by dimer nucleation at the step edge. Our results are in agreement with recent continuum theoretical predictions, and experiments on Cu(1,1,17) vicinal surfaces.

Evolution of substance P immunofluorescent nerves in callus tissue during fracture healing.

Tibial fractures were experimentally produced in rats. The fractures were allowed to heal spontaneously. Samples of callus tissue were studied by a specific immunohistochemical method for substance P, the peptide which is found in sensory nerves and probably plays a role in nociceptive nerve transmission. The control periosteum contained a rich network of substance P immunofluorescent nerves. The early callus tissue also contained such sensory nerves, the peak frequency of which was at the end of the second week. It is proposed that the substance P-containing nerves play a protective nociceptive role during fracture healing.

A prospective study of the treatment of severe tears of the lateral ligament of the ankle.

A prospective randomized clinical study was undertaken to compare bandaging, plaster cast immobilisation and operative treatment for recent tears of the lateral ligament of the ankle. The follow-up period was two years. Subjectively, only the fear of giving-way showed a clear difference in favour of operative repair. Objective evaluation, including stress radiographs, demonstrated no statistical differences between the three methods of treatment. Although bandaging appeared somewhat less satisfactory with respect to the resulting stability of the ankle, the differences were not statistically significant. The lateral ligament in patients over 40 years of age showed a statistically significant tendency to heal less well than that of younger patients. Severe ankle sprains in patients under 40 years of age should preferably be treated by operation, especially in younger patients and if the person is physically active. Lateral ligament tears in patients over 40 years of age should be treated conservatively and a secondary reconstruction carried out later, if necessary.

Acute dislocation of the patella. Clinical, radiographic and operative findings in 64 consecutive cases.

The clinical, radiographic and operative findings in 64 consecutive acute dislocations of the patella were analyzed. Both patellofemoral joints were symptomless before dislocation in 58 patients. The sulcus angle of the femur on the affected side was larger than on the contralateral side in one half, and a fresh marginal patellar fracture was demonstrated in one third of the cases. The stability of the patella could not be reliably estimated in tangential views taken with the knee in 20 degrees flexion; especially false negative findings were numerous.

Scanning electron microscopical study of the effects of crystalloid and water-soluble glucocorticoids on articular cartilage.

A comparative scanning electron microscopical study on the topical effects of glucocorticoids on rat knee cartilage was undertaken. Water-soluble and crystalloid 'depot'-form glucocorticoids were tested. Cartilage destruction was dependent on the number of injections and was clearly more pronounced in the knees injected with crystalloid glucocorticoid. We conclude that repeated injection of the joint with glucocorticoids should be given only after careful consideration of the clinical state.

The halo brace in unstable fractures of the cervical spine: a review of 14 cases.

A series of 14 patients with unstable fractures of the cervical spine, treated initially with skull traction and a few days later with a halo-thoracic brace, is described. Nine of the injuries were fractures of the odontoid process and the rest were at various levels. No patient with major neurological defects was included in the halo brace treatment. The halo brace provides significant advantages, including immediate mobilization with less time in hospital and less nursing. The results of the present series are encouraging; stable conditions were achieved in all cases.

Flexor tendon division at "no-man's land" of the hand treated by primary suture and passive controlled mobilization.

Flexor tendon injuries to the no-man's land of the hand previously exclusively treated by delayed operation and tendon grafting can be treated successfully by primary suture and postoperative controlled passive mobilization. Ten patients with flexor divisions of fourteen fingers were operated on using a modified Kessler technique and mobilized passively under control. The outcome in two tendons was poor, in one it was fair and in all the others good. The reason for the poor result in the two cases was suture leakage. Primary tendon repair should be preserved for clean uncomplicated tendon divisions. Sufficient experience in surgery of the hand is necessary to achieve good results.

Healing of experimental ligament rupture: findings by scanning electron microscopy.

The medial collateral ligaments of the knee joints of 16 rats were cut. Sixteen ligaments were allowed to heal spontaneously while the others were immediately sutured under the microscope. Four sham-operated immobilized rats served as controls. The ligamentous healing was registered after 4-5 weeks of immobilization under a scanning electron microscope (SEM). In the control ligaments, collagen bundles of variable thickness were observed as the main supporting elements. Numerous thin fibers were seen between the bundles. The surgically corrected ligaments showed a microstructural picture often difficult to distinguish from the controls. The unsutured ligaments, however, showed a much more variable picture. In some unsutured cases ligamentous regeneration was blocked by extensive scar formation. In many unsutured cases, however, signs of ligamentous regeneration were observed. It was noted that the SEM is a useful and sophisticated tool for studies on ligament healing.