Phase synchronization analysis of prefrontal tissue oxyhemoglobin oscillations in elderly subjects with cerebral infarction

• Published in: Medical physics (Lancaster) Vol. 41; no. 10; pp. 102702 - n/a
• Main Authors: Han, Qingyu, Li, Zengyong, Gao, Yuanjin, Li, Wenhao, Xin, Qing, Tan, Qitao, Zhang, Manyu, Zhang, Yixun
• Format: Journal Article
• Language: English
• Published: United States American Association of Physicists in Medicine 01.10.2014
• Subjects: Aged; Algorithms; biochemistry; Biochemistry; Beer; Spirits; Wine; Vinegar; Microbiology; Enzymology; Mutation or genetic engineering; bioelectric potentials; Biological material, e.g. blood, urine; Haemocytometers; Biological signal processing; biological tissues; brain; cerebral infarction; Cerebral Infarction - physiopathology; cerebral oxygenation; Cochlear implants; Coherence; Digital computing or data processing equipment or methods, specially adapted for specific applications; diseases; Female; Fourier Analysis; Fourier transform spectroscopy; Frequency analyzers; functional connectivity; geriatrics; Humans; Hypertension - physiopathology; infrared spectra; Integral transforms; Male; medical signal processing; molecular biophysics; near‐infrared spectroscopy; neurophysiology; oxygen; Oxyhemoglobins - metabolism; Periodicity; Prefrontal Cortex - physiopathology; proteins; Rest; Signal Processing, Computer-Assisted; Spectroscopy, Near-Infrared - methods; Spectrum analysis; spontaneous oscillations; synchronisation; Synchronization in the nervous system; Time series analysis; Tissues; wavelet phase coherence; Wavelet transform; wavelet transforms; Wavelets
• ISSN: 0094-2405; 2473-4209; 2473-4209
• DOI: 10.1118/1.4896113

Purpose: This study aims to assess the phase relationship of prefrontal tissue oxyhemoglobin oscillations using wavelet phase coherence analysis of cerebral Delta [HbO2] signals in cerebral infarction (CI) patients during the resting state. Methods: Continuous recordings of near‐infrared spectroscopy signals were obtained from the left and right prefrontal lobes in 21 subjects with CI (Group CI, age: 76.6 ± 8.5 yr) and 21 healthy elderly subjects (Group Healthy, age: 69.0 ± 7.4 yr) during the resting state. The Group CI was further divide into two groups: CI with hypertension and CI without hypertension. The phase synchronization between left and right prefrontal Delta [HbO2] oscillations in four frequency intervals (I, 0.6–2 Hz; II, 0.145–0.6 Hz; III, 0.052–0.145 Hz; and IV, 0.021–0.052 Hz) was analyzed using wavelet phase coherence method. Results: The phase coherences in intervals III and IV were significantly lower in CI with hypertension than in healthy elderly subjects (F = 12.974, p = 0.001 for III and F = 10.073, p = 0.004 for interval IV). The phase coherence of CI without hypertension in interval III was significantly lower than in healthy elderly subjects (F = 9.909, p = 0.004). Also, the phase coherence in interval IV was significantly lower in CI with hypertension than in CI without hypertension (F = 5.665, p = 0.028). Also, the phase agreement in interval IV showed evident difference between Group CI with hypertension and without hypertension. Conclusions: The difference in phase characteristics of prefrontal tissue oxyhemoglobin oscillations between the CI patients and healthy elderly indicates altered phase synchronization. Moreover, the CI combined with hypertension would aggravate this process. This study provides new insight into the phase dynamics of cerebral oxygenation and may be useful in assessing the risk for stroke.