Disease Description (Causes and Symptoms)

Definition: Prosopagnosia is a symptom in which a person cannot recognize people's faces despite having no visual impairment or language disorder. Although they can recognize individual features such as the eyes, nose, and mouth, they cannot integrate the entire face to identify who the person is.
Pathophysiology: It occurs due to damage to the inferior occipitotemporal lobe, particularly areas involved in face recognition such as the fusiform face area. Right-sided lesions are important, but the condition is usually more pronounced when bilateral damage occurs.
Main causes: Cerebral infarction (stroke), cerebral hemorrhage, traumatic brain injury, brain tumors, degenerative diseases (e.g., Alzheimer's disease and semantic memory impairment), and congenital causes (developmental prosopagnosia).
Symptoms:
- Inability to recognize familiar people's faces (they may be identifiable through nonfacial cues such as their voice or clothing).
- Onset pattern: It may occur suddenly (with vascular or traumatic lesions) or worsen gradually (with degenerative diseases).
- Associated findings: Superior visual field defects, and sometimes color vision abnormalities or reading impairment (when associated visual areas are damaged).

Treatment Methods

Treatment of the underlying cause is the priority:
- Acute vascular lesions: Standard stroke treatment and prevention of recurrence (including antiplatelet or anticoagulant therapy and risk-factor management).
- Structural lesions (such as tumors): Appropriate surgery, radiation therapy, or anticancer treatment.
- Traumatic injury: Neurosurgical and rehabilitative treatment.
- Degenerative diseases: Standard medication and cognitive therapy for the underlying disease (e.g., Alzheimer's disease), although these do not completely correct face recognition itself.
Symptomatic and rehabilitative approaches:
- Training in compensatory strategies: Training to identify people using nonfacial cues such as their voice, gait, clothing, and name tags.
- Cognitive rehabilitation (visual recognition training), occupational therapy, speech therapy (when necessary), and psychosocial support.
- Assistive technology: Use of apps and devices that assist with identifying people (be aware of privacy concerns and the risk of malfunction).
Medication: There are no specific medications targeting face recognition itself. Medication for the underlying disease (such as dementia) should follow the relevant guidelines.
Precautions:
- Because the condition can cause social misunderstandings and isolation, family members and acquaintances should be informed, and environmental support is needed.
- When using assistive technologies such as smartphone apps, consider their accuracy and privacy issues.

Items/materials to prepare:
- A list of currently used medications (including prescriptions, OTC medications, and supplements).
- Copies of previous medical records and brain imaging results (such as MRI/CT), if available.
- Notes recording when the symptoms began and how they have progressed (whether they began suddenly or worsened gradually, with 2–3 example situations).
- A list of accompanying symptoms (memory decline, language impairment, visual field defects, headaches, etc.).
- Family history (developmental prosopagnosia, dementia, etc.).
- A caregiver or acquaintance who can accompany the patient (to help explain the situation).
Items that are helpful to submit or explain to the doctor in advance during the outpatient visit:
- Specific examples of not recognizing faces (when, where, and whose face was involved).
- Difficulties in daily life caused by the symptoms (social and occupational effects).
- Any recent history of brain injury (stroke, trauma, etc.) or cognitive decline.

What do you think is the cause of this symptom? What additional tests are needed?
What findings can be expected on MRI or neuropsychological testing? Is fMRI/FDG-PET needed?
How much improvement can be expected with treatment, and what is the prognosis?
What strategies do you recommend to reduce safety or social problems in daily life?
What goals and duration will rehabilitation (cognitive rehabilitation and occupational therapy) involve, and how effective is it?
How should I explain this to my family and workplace and ask for help?

Can MRI (or functional imaging) determine whether the damaged area is the inferior occipitotemporal lobe responsible for face recognition, and whether it is on the right or left? How does the lesion location affect the prognosis?
What additional tests are needed to distinguish whether the symptoms are developmental (congenital) or acquired (due to brain injury or dementia), such as the Cambridge Face Memory Test or a neuropsychological assessment?