• Rapidly developing delirium or dementia (over the course of a few weeks or months)
• Blurred vision (sometimes)
• Changes in gait (walking)
• Hallucinations
• Lack of coordination (for example, stumbling and falling)
• Muscle twitching
• Muscle stiffness
• Myoclonic jerks or seizures
• Nervous, jumpy feelings
• Personality changes
• Profound confusion, disorientation
• Sleepiness
• Speech impairment

CJD is rarely confused with other types of dementia (such as Alzheimer's disease) because in CJD, symptoms progress much more rapidly. Both forms of CJD are distinguished by extremely rapid progression from onset of symptoms to disability and death.

Early in the disease, a neurological and mental status examination will show memory problems and changes in other mental functions. Later in the course of the disease, a motor system examination will show muscle twitching and spasm, a strong startle response, and an increase in muscle tone. There may also be weakness and loss of mucle tissue (muscle wasting) and abnormal reflexes or increased normal reflex responses.

There is loss of coordination related to visual-spatial perception changes and changes in the cerebellum, the area of the brain that controls coordination (cerebellar ataxia). An eye examination shows areas of blindness that the person may not realize are present.

Tests used to diagnose this condition may include:

• Brain MRI
• EEG
• Spinal tap
• Blood tests to rule out other forms of dementia and to look for markers that sometimes accompany the disease

Ultimately, the disease can only be confirmed by brain biopsy or autopsy.