The symptoms that persist create an overall feeling of "brain fog". Significant changes in personality can be present, and will vary according to the underlying cause, the severity of the inflammation, and delays in treatment. Affected individuals may also have a variety of neurocognitive impairments such as difficulty processing information (e.g. poor concentration, slowed thought), difficulty with planning and making decisions, and substantial memory deficits. For many people, these deficits affect nearly all spheres of their daily activity, severely impacting overall daily functioning levels and posing a significant burden to families and caretakers. A variety of pain symptoms can be associated with ME, including chronic headaches and significant muscle pain (myalgia). Sleep disturbances including abnormal sleep patterns and "unrefreshing" sleep, where a person does not feel refreshed upon waking may also occur. Additional neurological symptoms may include an inability to focus vision, impaired depth perception, loss of proprioception, visual-spatial disorientation, sensitivity to sunlight, muscle weakness, unsteadiness, and poor coordination.