Background: Alzheimer's disease (AD) and Binswanger's disease (BD) are among the most common neurodegenerative disorders associated with cognitive impairment and dementia. Using energy of lasers with low output power of the red or near-infrared spectrum region called Photobiomodulation Therapy (PBMT), is an achievement in the development of methods for the treatment of these diseases. Aims: The present study investigates the impact of Transcatheter Intracerebral Laser Photobiomodulation Therapy (PBMT) on the reduction of cognitive, mental impairment and dementia in patients with various Alzheimer's Disease and Binswanger's Disease stages. Methods: For the research, we selected 62 patients suffering from dementia, aged 34-81 (mean age 72.75), 25 men (40.32%), 37 women (59.68%). Test Group 1 - 48 patients previously diagnosed with Alzheimer's Disease. According to dementia severity, patients were subdivided: preclinical stage (dementia level TDR-0) - 4, mild stage (dementia level TDR-1) - 16, moderately severe stage (dementia level TDR-2) - 21, severe stage (dementia level TDR-3) - 7. Test Group 2 - 14 patients with previously diagnosed Binswanger's Disease. According to dementia severity, the patients were subdivided: mild stage (dementia level CDR-1) - 9, moderately severe stage (dementia level CDR-2) - 5. All patients underwent Transcatheter Intracerebral Laser Photobiomodulation Therapy (PBMT). Results: Test Group 1. Thanks to angiogenesis and neurogenesis stimulation using Transcatheter Intracerebral Laser Photobiomodulation Therapy (PBMT), in all 48 (100%) cases, cerebral blood supply and microcirculation improved, cerebral involutive and atrophic changes decreased. Patients showed persistently decreasing dementia, cognitive and mental abilities improvement. The vast majority began to correspond to the group with a milder disease stage. Test Group 2. Due to angiogenesis and neurogenesis stimulation, all 14 (100%) cases demonstrated stable dementia reduction, restoration of cognitive, mental functions and daily life activities. Conclusion: Transcatheter Intracerebral Laser Photobiomodulation Therapy (PBMT) is an effective, physiologically based method of stimulating cerebral angiogenesis and neurogenesis for Alzheimer's Disease and Binswanger's Disease patients. Due to complex laser exposure, patients show cerebral collateral and capillary revascularization, tissue metabolism improvement and cerebral regenerative processes development. Clinically, this leads to stable dementia level decrease, cognitive functions restoration and improvement in patients’ quality of life. The resulting clinical effect lasts for many years.