​Agnosia


Agnosia is a rare disorder that makes you lose the ability to recognize objects, faces, voices, or places previously known. It is specific for a given sensory modality. 

There are three main types of agnosia: 

  • Visual: This is the most common type of agnosia, in which you are not able to recognize objects or faces. It includes:

    • Prosopagnosia, that is, the inability to identify faces even though the person is known 

    • Agnostic Alexia, that is, the inability to recognize written pieces (including letters and words)

    • Colour Agnosia, that is, the inability to discriminate between colours and therefore cannot name the colour

    • Object Agnosia, that is, the inability to name objects

    • Simultanagnosia, that is, the inability to recognize a whole image although individual details are recognized

  • Auditory: People with auditory agnosia are unable to recognize sounds and language to varying degrees, depending on the severity of the disease. It includes:

    • Auditory/verbal information agnosia, that is, the inability to hear words

    • Auditory agnosia, that is, the inability to hear environmental sounds such as a car starting or a dog barking

    • Receptive amu​sia, that is, the inability to hear music

  • Tactile: This type of agnosia is the inability to identify objects by touch.

Agnosia can result from: 

  • Strokes 

  • Brain injury 

  • Dementia

  • Tumour

  • Developmental disorders

  • Overexposure to environmental toxins

  • Other neurological conditions

The symptoms of agnosia, depending on the type of agnosia you may be suffering from, are as follows: 

  • Inability to recognize objects

  • Inability to recognize people

  • Inability to recognize sounds

  • Inability to recognize a familiar sound

  • Inability to recognize a familiar shape

  • Inability to recognize a familiar smell

  • Inability to recognize a familiar object

  • Inability to recognize a familiar person

  • Inability to identify a familiar stimulus 

If you or a loved one is facing similar symptoms, it is recommended that you consult with your doctor immediately. You can obtain additional information and expert medical advice from the Mind and Brain Service Line​ at The Aga Khan University Hospital.

Your time with your doctor may be limited, so make sure to prepare for your visit beforehand. Here are some tips to help get you started.

There is no specific test that confirms a diagnosis of agnosia. It is based on your doctor’s judgment about what is the most likely cause of your symptoms. Your doctor will attempt to rule out other causes of your symptoms such as:

  • General memory disorder

  • Capgras Syndrome (an irrational belief that a familiar person or place has been replaced with an imposter)

  • Mental retardation (intellectual disability suffered by people with lower than average IQ)

  • Dementia (type of disease associated with loss of memory and brain function)

  • Head Trauma (e.g. in a car accident)

  • Your doctor will also conduct a series of tests to determine what particular type of agnosia you may have including trying to identify sounds, objects, faces etc. A variety of psychophysical tests can be conducted to identify the nature of the process that is disrupted in an individual. 

Brain damage that causes agnosia may be identified through imaging techniques, including: 

  • Magnetic Resonance Imaging (MRI) scan: in this test, a machine uses a magnetic field and radio waves to create detailed images of your brain. 

  • Computerized Tomography (CT) scan: this is an imaging method that creates a two-dimensional image of the brain using X-ray technology.

There is no direct cure for agnosia but there are therapies available to help manage it. The primary difficulty in treating is that you are unaware of the problem or may refuse to recognize it as such. Lack of awareness of the problem can lead to denial of its existence and consequently lead you to resist seeking help or treatment. 

Once you show the willingness to seek treatment, your doctor can offer you comprehensive, state-of-the-art medical care. Forms of available treatment are:

  • Verbal strategies: Using verbal descriptions of objects or people that you may not recognize will help you to recognize them based on this description more easily than through visual cues.

  • Alternate cues: These may be useful if you are suffering from environmental agnosia. Alternate cues include colour cues, definitive characteristics (such as a scar or birthmark) in order to recognize the individual.

  • Organizational strategies: These are helpful if you have visual agnosia, making it easier to identify objects as opposed to relying solely on visual cues.

The Aga Khan University Hospital offers various support services to help with managing or recovering from the disease or condition. These include but are not limited to nutrition, physiotherapy, rehabilitation, specialized clinics and some patient support groups. Your doctor or nurse will advise you accordingly.

The Aga Khan University Hospital offers financial assistance to those who are in need and fulfil the eligibility criteria. For further information, you can contact the Patient Welfare Department. You can find the contact number of the Patient Welfare Department in the 'Important Numbers' section on the website homepage.

The financial counselling staff is available during office hours, at the main PBSD (Patient Business Services Department), to answer your financial queries on treatments' costs and authorize admissions on partial deposit as per hospital policies allow. The financial counsellor in the emergency room is open 24/7. You can find the contact number of the Patient Business Services in the 'Important Numbers' section on the website homepage.

Your doctor and or nurse will give you specific instructions about the prescribed medication. Please ensure that you take or use the prescribed medicine as advised. It can be dangerous to your health if you self-prescribe. Please inform the doctor or nurse beforehand if you have experienced any adverse reactions to any medications in the past. If you experience any symptoms of drug poisoning, overdose or severe reaction please contact the Pharmacy Service at The Aga Khan University Hospital immediately. You can find the contact number of the Pharmacy Services in the 'Important Numbers' section on the website homepage.



The information provided on our website is for educational purposes and not intended to be a substitute for medical advice, diagnosis or treatment. You should always seek the advice of your doctor or other healthcare professional provider. ​