Publications by authors named "H Helakari"
Introduction: The cerebrospinal fluid dynamics in the human brain are driven by physiological pulsations, including cardiovascular pulses and very low-frequency (< 0.1 Hz) vasomotor waves. Ultrafast functional magnetic resonance imaging (fMRI) facilitates the simultaneous measurement of these signals from venous and arterial compartments independently with both classical venous blood oxygenation level dependent (BOLD) and faster arterial spin-phase contrast.
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- Misdiagnosis of Alzheimer's disease, behavioral variant of frontotemporal dementia (bvFTD), and schizophrenia is common due to overlapping symptoms, particularly in early-onset cases.
- A study on 234 participants using BOLD signal variability revealed that bvFTD patients showed significantly higher variability compared to those with AD and schizophrenia, correlating with clinical assessment scores.
- The coefficient of variation (CV) demonstrated strong diagnostic accuracy for bvFTD and showed progression over a year, indicating its potential as a biomarker for distinguishing bvFTD from AD and SZ and monitoring disease progression.
Background/objective: Obesity is a risk factor for several brain-related health issues, and high body-mass index (BMI) is associated with an increased risk for several neurological conditions, including cognitive decline and dementia. Cardiovascular, respiratory, and vasomotor brain pulsations have each been shown to drive intracranial cerebrovascular fluid (CSF) flow, which is linked to the brain metabolite efflux that sustains homeostasis. While these three physiological pulsations are demonstrably altered in numerous brain diseases, there is no previous investigation of the association between physiological brain pulsations and BMI.
View Article and Find Full Text PDFThe eye possesses a paravascular solute transport pathway that is driven by physiological pulsations, resembling the brain glymphatic pathway. We developed synchronous multimodal imaging tools aimed at measuring the driving pulsations of the human eye, using an eye-tracking functional eye camera (FEC) compatible with magnetic resonance imaging (MRI) for measuring eye surface pulsations. Special optics enabled integration of the FEC with MRI-compatible video ophthalmoscopy (MRcVO) for simultaneous retinal imaging along with functional eye MRI imaging (fMREye) of the BOLD (blood oxygen level dependent) contrast.
View Article and Find Full Text PDFIntroduction: Sleep increases brain fluid transport and the power of pulsations driving the fluids. We investigated how sleep deprivation or electrophysiologically different stages of non-rapid-eye-movement (NREM) sleep affect the human brain pulsations.
Methods: Fast functional magnetic resonance imaging (fMRI) was performed in healthy subjects ( = 23) with synchronous electroencephalography (EEG), that was used to verify arousal states (awake, N1 and N2 sleep).