Could Lightening Like Flashes In Head Be A Symptom Of Dementia?

Hello, i am the carer for a 71 year old woman who has paralysis of the left side of her body. She also has stage 5-6 vascular dementia. She has asked me to find some information on something she is experiencing at the moment. She tells me she has lightening like flashes in her head and wonders if this is part of her dememtia ?