Cognitive Functional Impairment and Hemodynamic Changes in Patients with Symptomatic Leukoaraiosis

Objective: The pathogenesis of leukoaraiosis is still unclear. Many studies have determined that changes in the hemodynamics associated with leukoaraiosis, impaired cerebrovascular reserve, and intracranial hypoperfusion can lead to various clinical manifestations such as motor or cognitive impairment. The purpose of this study was to investigate the relationship between cognitive functional changes and imaging characteristics in patients with symptomatic leukoaraiosis, and to observe the corresponding changes in hemodynamics. Methods: A total of 203 Han patients (aged 43 - 93 years) with symptomatic leukoaraiosis were included in this study. Head magnetic resonance imaging was semi-quantified according to the Fazekas grading standard. Then, each patient was evaluated in terms of cognitive (Montreal scale) and executive function (trail-making test A [TMTA] and TMTB). Specifically, the TMTA asks patients to connect points on a piece of paper numbered from 1 to 25 in order and the TMTB asks patients to arrange numbers and letters in alternating order. In the current work, revised versions of these tests used are to include numbers in square and circular shapes where the shapes needed to be arranged in alternating order. The time required to complete the TMTA and TMTB was recorded. The changes in the blood flow velocity of the middle cerebral artery were also observed using routine Transcranial Doppler ultrasound and the breath-holding test. The dynamic curves of blood flow velocity during the breath-holding test were examined. Results: The cognitive and executive functions of patients with leukoaraiosis are related to the classification of image-based disease characteristics. In this sense, the more serious the leukoaraiosis is, the larger the impairment of cognitive and executive function is. According to the breath-holding test, the peak pattern of the blood flow velocity in the middle cerebral artery was significantly different between the various grades of leukoaraiosis. The peak type of Fazekas grade 0 and I was in the same direction, while the peak type of Fazekas grade II and III was significantly opposed (both p Conclusions: The impairment of cognitive and executive functions in patients with leukoaraiosis correlates with the severity of image-based disease manifestations, which are generally depicted as intracranial hypoperfusion.

Complex Frequency Features for TCD Signal Analysis

In this paper, we report on using pattern recognition techniques for embolic signal(ES) detection based on transcranial doppler ultrasound(TCD) audio data collected via machine EMS-9(from Shenzhen Delicate Electronics, Co. Ltd).Firstly, we adopted complex discrete fourier transform to get spectra of audio recordings; secondly, we used principal component analysis(PCA) for the visualization of selected signals, which makes it easy and intuitive to verify whether a signal contains an embolic component; finally we designed the classifier with support vector machines(SVM) for detection. With contrast to traditional methods of ES detection systems, the proposed approach considers two channel signals from the audio data collected by single transducer, and there is no predefined features for classification. The primary experimental results on real data are promising.