While there are many possible causes of dementia, the symptoms are what define the condition. In order to de diagnosed with dementia, a person needs to have difficulty in more than one cognitive area, e.g. memory and language ability, or memory and reasoning ability. Cognitive problems that are common in dementia include:

• Memory loss that tends to worsen with time.
• Difficulty concentrating.
• Reduced problem-solving skills.
• Impaired judgment and reasoning capability.
• Impaired recognition (agnosia) of people or objects.
• Hallucinations or delusions.
• Altered sleep patterns.
• Impaired skilled motor function (apraxia).
• Sever confusion or disorientation.
• Absent or impaired language ability (aphasia).
• Personality changes.
• Irritability.
• Indecisiveness.
• No emotional responses (flat affect) or inappropriate responses.
• Inability to function in social situations or social isolation.
• Decreased concern for appearance.
• Loss of ability to care for oneself.
• Decreased interest in daily living activities.