Prosopagnosia

Key points at a glance

Key points of this disease

• Prosopagnosia is a neuro-ophthalmologic disorder characterized by selective impairment of face recognition and identification, broadly divided into perceptual and associative types.
• Developmental prosopagnosia (DP) occurs in approximately 2–2.5% of the general population, while acquired prosopagnosia (AP) results from cerebrovascular disease, tumors, trauma, etc.
• Lesions are most often located in the bilateral inferior occipitotemporal lobes (especially the fusiform face area); unilateral cases overwhelmingly involve the right hemisphere.
• It is frequently accompanied by cerebral color blindness, topographic agnosia, and homonymous hemianopia.
• Diagnosis involves a combination of multiple neurocognitive function tests (CFMT, BFRT, etc.) and imaging tests, but a gold standard has not been established.
• There is no established effective treatment; management focuses on treating the underlying disease and teaching compensatory strategies.
• In posterior circulation stroke, prosopagnosia may be the only neurological sign, so careful attention is needed to avoid overlooking it.

1. What is prosopagnosia?

Prosopagnosia, also called face blindness, is a neuro-ophthalmologic disorder characterized by a selective impairment in the ability to recognize and identify faces. The term originates from the Greek words “prosopon” (face) + “a” (negation) + “gnosia” (knowledge). It is classified as a type of visual agnosia, where individuals cannot recognize family members’ faces or expressions but can identify them by voice or gestures. Sometimes, one’s own face in the mirror may appear unfamiliar.

In 1947, Joachim Bodamer first comprehensively described the condition and proposed the term “prosopagnosia.” ¹⁾²⁾

Classification

Perceptual type

Definition: The inability to perceive or recognize faces.

Responsible region: Associated with damage to the medial occipital lobes (fusiform gyrus) bilaterally.

Associative Type

Definition: Faces can be perceived, but identification and semantic processing are impaired.

Responsible site: Associated with lesions of the anterior temporal lobe (amygdala and hippocampus).

Furthermore, based on the pathogenesis, it is broadly divided into two types.

• Developmental type (DP): Lifelong difficulty in face recognition without obvious brain damage. Autosomal dominant and polygenic inheritance patterns have been suggested. ¹⁾ The prevalence in the general population is approximately 2–2.5% in adults and 1.2–4% in children. ³⁾ It frequently co-occurs with autism spectrum disorder, Alzheimer’s disease, and epilepsy. ³⁾
• Acquired type (AP): Caused by brain damage. The frequency is unknown, but case reports are scattered. ²⁾

Capgras syndrome (a delusion that close relatives are impostors) has also been suggested to involve the same brain regions as prosopagnosia.

Q How common is prosopagnosia?

A

The developmental type is present in approximately 2–2.5% of the general adult population and 1.2–4% of children. ³⁾ The exact frequency of the acquired type is unknown, but case reports are scattered. ²⁾

2. Main Symptoms and Clinical Findings

Subjective Symptoms

• Difficulty recognizing familiar faces: Unable to recognize faces of known individuals such as family, friends, and colleagues. ¹⁾
• Difficulty identifying people in photographs: Cannot tell who the person in a photograph is. ¹⁾
• Distorted perception of faces: Some patients report that faces appear distorted, like a “clown.” In a 58-year-old woman with right occipital lobe hemorrhage, distortion of the mouth area was particularly noticeable. ¹⁾
• Mirror-image prosopagnosia: Some individuals cannot recognize their own face in a mirror or photograph.
• Use of compensatory cues: Attempts to identify individuals using non-facial cues such as voice, clothing, or gestures. ²⁾
• Comorbid topographic disorientation: Often accompanied by navigation difficulties. ¹⁰⁾
• Psychosocial impact: Leads to anxiety, depression, and social isolation. ³⁾

Clinical Findings (Findings Confirmed by Physician Examination)

• Visual acuity: Near and distance vision may be normal.
• Homonymous hemianopia: Left homonymous hemianopia suggests a lesion in the right occipital lobe. It may be accompanied by left superior homonymous quadrantanopia (in cases of right temporal lobe lesions). ⁸⁾
• Superior quadrantanopia: Often occurs in cases of bilateral temporo-occipital lobe damage.
• Complicated by cerebral color vision abnormality: Caused by damage to the color vision center in the lingual gyrus and fusiform gyrus of the ventral occipital lobe. It is binocular, associated with good visual acuity and upper quadrantanopia, and often accompanied by prosopagnosia.
• Complicated by topographic agnosia: More common in cases of bilateral temporo-occipital lobe damage.
• Pau city of neurological findings: Focal motor deficits are often absent, and the NIH Stroke Scale may be 0. ¹⁾

Assessment of higher-order visual dysfunction

Patients’ symptoms are often vague, so it is important to perform specific tests based on the symptoms predicted from the lesion location.

3. Causes and Risk Factors

Causes of Acquired Type (AP)

• Cerebrovascular disorders: Cerebral infarction in the posterior circulation (especially the posterior cerebral artery territory) and intracranial hemorrhage are the most common. Cerebral infarction of the posterior cerebral artery is the most frequent cause of occipital lobe damage.
• Brain tumors: Primary brain tumors (incidence 10.8/100,000 person-years), metastatic brain tumors (24.2/100,000 person-years). Compression of the inferior longitudinal fasciculus (ILF) may be a cause. ²⁾⁸⁾⁹⁾
• Infections/encephalitis: Encephalitis including anti-NMDA receptor encephalitis, neurodegenerative diseases (e.g., Alzheimer’s disease), head trauma. ²⁾
• COVID-19: There are reports of persistent prosopagnosia after COVID-19 infection (e.g., a 28-year-old woman noticed face recognition difficulties 2 months after onset). ¹⁰⁾
• Migraine: Multiple reports of transient prosopagnosia during the aura phase. In a study of 143 migraine patients, 7 (about 5%) experienced prosopagnosia. ⁶⁾
• Others: epilepsy, carbon monoxide poisoning, cerebral venous thrombosis (right transverse sinus), etc. ⁹⁾⁶⁾

Causes and Epidemiology of Developmental Prosopagnosia (DP)

• Persistent difficulty recognizing faces throughout life without obvious brain damage.
• An autosomal dominant inheritance pattern has been suggested. ¹⁾
• In children with cortical visual impairment (CVI), prosopagnosia is one of the most common abnormalities, observed in 15 out of 20 cases (75%).

Risk Factor Checklist

History of head trauma, hypertension, diabetes, coronary artery disease, stroke, Alzheimer’s disease, Parkinson’s disease, and current medications.

Prevention and Daily Care

The main cause of acquired prosopagnosia is cerebrovascular disease. Management of hypertension, diabetes, and arrhythmias is an important preventive measure. If you suddenly notice difficulty recognizing faces, seek medical attention promptly as it may indicate a stroke.

Q Can migraines also cause prosopagnosia?

A

There are multiple reports of transient prosopagnosia occurring during the aura phase of migraines. ⁶⁾ In a study of 143 migraine patients, about 5% experienced prosopagnosia, which is thought to be related to the proximity of the fusiform gyrus and migraine-related brain regions. ⁶⁾

4. Diagnosis and Examination Methods

Diagnosis is made clinically. No single gold standard has been established.

Neurocognitive function tests

Major facial recognition tests are shown below.

Test name	Abbreviation	Assessment content
Cambridge Face Memory Test	CFMT	Face memory and identification
Benton Facial Recognition Test	BFRT	Face matching
Cambridge Face Perception Test	CFPT	Face similarity judgment
Bielefeld Famous Faces Test	BFFT	Identification of famous people

• CFMT: Memorize 6 faces and identify them from 3 choices. The most widely used test. In COVID-19 sequelae cases, CFMT showed clear impairment at 55.6% (normal average 80%). ¹⁰⁾ In TKI-treated cases, it improved from 44% before treatment to 75% after 1 month of treatment. ⁹⁾
• BFRT/CFMT: Assess face matching and are suitable for evaluating associative prosopagnosia.
• Famous Faces Test: COVID-19 cases could identify only 29.2% of 48 recognized faces (normal 83.6%). ¹⁰⁾
• Self-Report Questionnaire: Free online questionnaires for prosopagnosia are also available.

Imaging Diagnosis

• MRI/CT: Essential for identifying the lesion site. Diagnosis is made using brain MRI or CT, and the findings are correlated with visual field defects and associated neurological symptoms.
• DTI (Diffusion Tensor Imaging): Can evaluate the relationship between abnormalities in the inferior longitudinal fasciculus (ILF) and face recognition disorders. ⁸⁾
• fMRI: Can assess activity in the fusiform face area (FFA), occipital face area (OFA), and posterior superior temporal sulcus (pSTS). ⁴⁾

Differential Diagnosis

It is necessary to rule out psychogenic visual disturbance, psychiatric disorders (including Capgras syndrome), and metabolic diseases. ¹⁾

Caution: Do not miss posterior circulation stroke

Posterior circulation stroke is approximately 2.5 times more likely to be missed than anterior circulation stroke (37% vs 16%). Since prosopagnosia may be the only symptom, differentiation from stroke is important. ¹⁾

Q Is there a standard test for the definitive diagnosis of prosopagnosia?

A

A single gold standard has not been established. Evaluation is performed using a combination of multiple neurocognitive function tests such as CFMT and BFRT, along with identification of lesion sites via MRI/CT. Self-assessment questionnaires can also be used as supplementary tools.

5. Standard Treatment

Currently, there is no established effective treatment for prosopagnosia. Treatment of the underlying disease and prevention of further brain damage are the top priorities.

Treatment of underlying disease

• In case of cerebral infarction: Consider thrombolytic therapy with t-PA or endovascular treatment in the very early stage. Administer antiplatelet drugs (e.g., aspirin) or anticoagulants (e.g., warfarin) to prevent recurrence. In cardioembolic stroke, it is important to search for the embolic source.
• In case of metastatic brain tumor: Conservative treatment with corticosteroids (dexamethasone 16 mg/day) and mannitol osmotic therapy. Complete recovery has been reported. ²⁾ Options also include surgical resection plus Gamma Knife radiosurgery. ⁸⁾
• In case of brain metastasis from EGFR-mutant lung adenocarcinoma: Administration of a tyrosine kinase inhibitor (osimertinib 80 mg/day) led to tumor shrinkage within one month and recovery from prosopagnosia (CFMT 44%→75%) in one case. ⁹⁾

Compensatory Treatment

• Verbalization training of facial details: May be effective for retraining face recognition ability, but evidence is limited.
• Use of non-facial cues: Instruct patients to use cues other than the face, such as voice, clothing, and gestures.
• Visual rehabilitation: If accompanied by reduced vision, low-vision rehabilitation is recommended.

Spontaneous Recovery

Rarely, spontaneous recovery occurs. There is a report of complete recovery in about 8 weeks in a case of right occipital lobe hemorrhage. ¹⁾ The prognosis of visual field defects after cerebral infarction is poor in elderly patients, but recovery may occur in younger patients.

Surgical Precautions

When resecting metastatic brain tumors, even in the non-dominant hemisphere, preoperative planning using DTI-based tractography is important for surgeries near the ILF. There are reports of worsened prosopagnosia postoperatively. ⁸⁾

Q Can prosopagnosia be cured?

A

There is no established treatment, and spontaneous recovery is rare. Improvement may occur with treatment of the underlying disease (e.g., cerebral infarction, tumor). ¹⁾²⁾ Training in compensatory strategies (using cues other than the face, such as voice, clothing, and gestures) has shown some effectiveness.

6. Pathophysiology and Detailed Mechanisms

Visual Information Processing Pathways

Visual information is first received in the V1-V2 visual cortex and then transmitted to the V3-V5 visual association areas.

• Ventral stream = “what” pathway: Involved in form and color vision in area V4, and leads to the temporal lobe for object recognition.
• Dorsal stream = “where” pathway: Involved in spatial relationships and motion vision in area V5, and leads to the parietal lobe.

Neural network for face recognition

Core network:

• Occipital face area (OFA): Processes initial face structure. ⁴⁾
• Fusiform face area (FFA): Processes facial identity, with right hemisphere dominance. ⁴⁾
• Posterior superior temporal sulcus (pSTS): Processes dynamic features such as expressions. ⁴⁾

Extended network: The anterior temporal lobe (biographical and semantic information), amygdala/limbic system (emotional processing), and intraparietal sulcus (attention) are involved. ⁴⁾

Role of the inferior longitudinal fasciculus (ILF)

The inferior longitudinal fasciculus is a white matter fiber bundle connecting the occipital lobe and the anterior temporal lobe, corresponding to part of the ventral pathway. Damage to the ILF leads to disruption of the face recognition network. There is a tendency for right-sided predominance. ⁸⁾ Unlike glial tumors, brain metastases tend to displace rather than infiltrate white matter fibers, resulting in high accuracy of DTI tractography. ⁸⁾

Lesion location

• Usually, both inferior occipitotemporal lobes are affected.
• In unilateral cases, the lesion is almost always on the right side.
• Responsible site for apperceptive type: bilateral medial occipital lobes.
• Responsible site for associative type: left medial temporo-occipital region (lingual gyrus, fusiform gyrus, parahippocampal gyrus, posterior inferior temporal gyrus).

Neural Basis of Developmental Type (DP)

A 25-year review (55 studies, 63 studies) has revealed the following: ⁴⁾

Manippa et al. (2023) conducted a scoping review integrating 25 years of neuroscientific findings. In DP, morphological, functional, and electrophysiological abnormalities are observed throughout the ventral visual pathway, and functional and anatomical connectivity between FFA-OFA and other face-sensitive regions is significantly impaired. fMRI studies show reduced face-selective responses in the right FFA and shrinkage of FFA clusters in DP. ERP studies show that N170 (a negative occipitotemporal potential at 150–200 ms), a marker of face-selective processing, exhibits abnormal patterns in DP. ⁴⁾

Holistic Processing Impairment

Face recognition depends on two mechanisms: configural processing and featural processing. ⁷⁾

Leong et al. (2025) showed that in patients with acquired prosopagnosia, impairment of the face inversion effect persists, while the part-whole effect and composite face effect may be preserved. This task-specific impairment persisted at reassessment 4 years later. ⁷⁾

---

7. Latest Research and Future Perspectives (Research-stage Reports)

For patients: Please read this carefully

The following content is currently at the research stage or in clinical trials, and is not standard treatment available at general hospitals. It is reference information for professionals regarding future medical developments.

Pharmacotherapy and nerve stimulation

Ma et al. (2023) examined intranasal oxytocin administration in 10 DP patients and 10 controls. Performance on two face processing tests improved under oxytocin inhalation. ³⁾

Non-invasive brain stimulation methods are also being studied. ³⁾

• Transcranial direct current stimulation (tDCS): Improvement in cognitive task performance has been reported. There is a report of improvement in associative prosopagnosia after COVID-19 with a combination of tDCS and symbolic art therapy.
• Transcranial random noise stimulation (tRNS): Improvement in neuroplasticity in perceptual learning has been reported, and combined effects with cognitive training are expected.
• Galvanic vestibular stimulation (GVS): Improvement in face perception has been reported in a 61-year-old patient with right brain damage.

Wearable Devices

Ma et al. (2023) developed an Android app + wearable eyepiece system with real-time face recognition mode and home training mode. Improvement in recognition was confirmed using inverted face simulations. ³⁾

Intervention Strategies for Children

Ma et al. (2023) organized intervention strategies for children with DP/AP, reporting restorative strategies (gaze scanning path training, facial feature discrimination training, holistic face processing training) and compensatory strategies (caricaturing, Feature Naming, semantic association). Feature Naming training was conducted in 14 sessions over one month in an 8-year-old DP patient, resulting in significant improvement in face recognition. ³⁾

Association with COVID-19

Kieseler et al. (2023) surveyed 54 patients with long COVID and found that over half reported reduced visual recognition and navigation abilities, suggesting that higher-order visual impairments may not be uncommon in long COVID. ¹⁰⁾

Neurocomputational approach

Faghel-Soubeyrand et al. (2024) used EEG and DNN model correspondence analysis to show that in patients with acquired prosopagnosia, the similarity of semantic processing is reduced from the P100 stage and persists across N170 and N400. This pattern was opposite to that of super-recognizers. ⁵⁾

---

8. References

1. Lampley P, Saggio MD, Boulet ML, et al. A Rare Case of Prosopagnosia Related to Intracranial Hemorrhage. Cureus. 2023;15(10):e47001.

2. Ivanova NI, Kyuchukova DM, Tsalta-Mladenov ME, et al. Prosopagnosia Due to Metastatic Brain Tumor: A Case-Based Review. Cureus. 2024;16(3):e57042.

3. Ma W, Xiao Z, Wu Y, et al. Face Blindness in Children and Current Interventions. Behav Sci. 2023;13(8):625.

4. Manippa V, Palmisano A, Ventura M, Rivolta D. The Neural Correlates of Developmental Prosopagnosia: Twenty-Five Years on. Brain Sci. 2023;13(10):1465.

5. Faghel-Soubeyrand S, Richoz AR, Woodhams J, et al. Neural computations in prosopagnosia. Cereb Cortex. 2024;34(5):bhae172.

6. Ley S. An Overview of Prosopagnosia as a Symptom of Migraine: A Literature Review. Curr Pain Headache Rep. 2025;29(1):33.

7. Leong BQZ, Ismail AMH, Estudillo AJ. Persistent task-specific impairment of holistic face processing in acquired prosopagnosia. Sci Rep. 2025;15(1):7892.

8. Weiss HK, Pacione DR, Galetta S, Kondziolka D. Prosopagnosia associated with brain metastasis near the inferior longitudinal fasciculus in the nondominant temporal lobe. J Neurosurg Case Lessons. 2021;1(25):CASE21130.

9. Soyama S, Matsuda R, Hontsu S, et al. Treatment of transient prosopagnosia with a tyrosine kinase inhibitor in a case of brain metastasis from EGFR-mutated lung adenocarcinoma. Surg Neurol Int. 2022;13:286.

10. Kieseler ML, Duchaine B. Persistent prosopagnosia following COVID-19. Cortex. 2023;163:1-15.