Global Transient Amnesia as the Predominant Symptom of Cardiac Myxoma: A Case Report.

BACKGROUND The most common neurological symptoms from cardiac myxoma-induced stroke include territories of middle cerebral arteries, rendering posterior stroke less common. Although transient global amnesia usually has a benign prognosis, amnesia in the setting of concerning cerebellar symptoms should raise the suspicion for posterior circulation involvement. These benign-appearing symptoms can be manifestations of an acute cerebrovascular accident (CVA). This unusual presentation can delay workup for underlying pathology. CASE REPORT A 67-year-old woman presented to the local emergency department after an episode of global amnesia that lasted about 15 minutes and was associated with some dizziness. The patient also reported a history of chronic disequilibrium. The head CT scan was negative for any acute findings. A follow-up MRI of the brain demonstrated acute small lacunar infarcts within the left cerebellum and right parietal lobe. An echocardiogram was performed due to concern for the cardioembolic source, which revealed left atrial myxoma. She was transferred to a tertiary center for immediate surgical intervention due to the high risk of embolization associated with the condition. The patient subsequently underwent successful surgical excision of the lesion. CONCLUSIONS Cardiac myxoma, although a rare cause of posterior stroke, needs prompt intervention as it is associated with a high risk of systemic embolization, including recurrent CVA. Transient global amnesia is an atypical presentation of cardiac myxoma that can easily be overlooked, delaying timely diagnosis and prompt intervention. Early recognition and surgical resection are crucial to prevent potentially life-threatening consequences.

Diagnostic yield of diffusion-weighted brain MR imaging in patients with cognitive impairment: Large cohort study with 3,298 patients.

OBJECTIVE: There is a paucity of large cohort-based evidence regarding the need and added value of diffusion-weighted imaging (DWI) in patients attending outpatient clinic for cognitive impairment. We aimed to evaluate the diagnostic yield of DWI in patients attending outpatient clinic for cognitive impairment. MATERIALS AND METHODS: This retrospective, observational, single-institution study included 3,298 consecutive patients (mean age ± SD, 71 years ± 10; 1,976 women) attending outpatient clinic for cognitive impairment with clinical dementia rating ≥ 0.5 who underwent brain MRI with DWI from January 2010 to February 2020. Diagnostic yield was defined as the proportion of patients in whom DWI supported the diagnosis that underlies cognitive impairment among all patients. Subgroup analyses were performed by age group and sex, and the Chi-square test was performed to compare the diagnostic yields between groups. RESULTS: The overall diagnostic yield of DWI in patients with cognitive impairment was 3.2% (106/3,298; 95% CI, 2.6-3.9%). The diagnostic yield was 2.5% (83/3,298) for acute or subacute infarct, which included recent small subcortical infarct for which the diagnostic yield was 1.6% (54/3,298). The diagnostic yield was 0.33% (11/3,298) for Creutzfeldt-Jakob disease (CJD), 0.15% (5/3,298) for transient global amnesia (TGA), 0.12% (4/3,298) for encephalitis and 0.09% (3/3,298) for lymphoma. There was a trend towards a higher diagnostic yield in the older age group with age ≥ 70 years old (3.6% vs 2.6%, P = .12). There was an incremental increase in the diagnostic yield from the age group 60-69 years (2.6%; 20/773) to 90-99 years (8.0%; 2/25). CONCLUSION: Despite its low overall diagnostic yield, DWI supported the diagnosis of acute or subacute infarct, CJD, TGA, encephalitis and lymphoma that underlie cognitive impairment, and there was a trend towards a higher diagnostic yield in the older age group.

Sensitivity of diffusion-weighted magnetic resonance imaging in transient global amnesia as a function of time from symptom onset.

BACKGROUND: The objective was to systematically evaluate the sensitivity of diffusion-weighted magnetic resonance imaging (DW-MRI) for transient global amnesia (TGA) across various time frames compared to the reference-standard clinical criteria. METHODS: All indexed publications related to TGA and MRI through June 2020 were retrieved by a medical librarian. Two independent reviewers identified original research studies of adults with a clinical diagnosis of TGA using Caplan and Hodges and Warlow criteria (reference standard) who were evaluated with DW-MRI. Pooled estimates and its 95% confidence intervals (CI) for the proportion of acute TGA patients with positive DW-MRI (i.e., sensitivity) were obtained using random-effects meta-analysis for various time frames. Quality assessment was performed using the revised Quality of Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. RESULTS: After screening 665 reports, we identified 81 potentially relevant studies. Twenty-three studies representing 1688 patients met eligibility criteria, but not all studies had data available for meta-analysis. The pooled sensitivity (also described as positivity rate) of DW-MRI was 15.6% (95% CI = 2.6%-35.0%) between 0 and 12 h from symptom onset, 23.1% (95% CI = 6.1%-45.7%) at 0-24 h, 72.8% (95% CI = 40.8%-96.3) at 12-24 h, 68.8% (95% CI = 44.8%-88.8%) at 24-36 h, 72.4% (95% CI = 59.8%-83.5%) at 36-48 h, 82.8% (95% CI = 54.7%-99.6%) at 48-60 h, 66.9% (95% CI = 47.5%-83.9%) at 60-72 h, and 72.0% (95% CI = 30.1%-100.0%) at 72-96 h. There was significant concern for risk of bias in the QUADAS-2 domains of patient selection and index test, yielding a low level of certainty in the pooled estimates. CONCLUSION: DW-MRI lesions are uncommon in patients with TGA early after symptom onset, but the sensitivity (i.e., positivity rate) of DW-MRI increases with time. Despite the limited quality of existing evidence, obtaining an early DW-MRI in patients with clinical diagnosis of TGA in the acute setting is likely a low-yield test.

Conventional cardiovascular risk factors in Transient Global Amnesia: Systematic review and proposition of a novel hypothesis.

Transient Global Amnesia (TGA) is an enigmatic amnestic syndrome. We conducted a systematic review to investigate the relationship between the conventional cardiovascular risk factors and TGA. MEDLINE, CENTRAL, EMBASE and PsycINFO were comprehensively searched and 23 controlled observational studies were retrieved. The prevalence of hypertension, diabetes mellitus, dyslipidemia and smoking was lower among patients with TGA compared to Transient Ischemic Attack. Regarding the comparison of TGA with healthy individuals, there was strong evidence suggesting a protective effect of diabetes mellitus on TGA and weaker evidence for a protective effect of smoking. Hypertension was associated with TGA only in more severe stages, while dyslipidemia was not related. In view of these findings, a novel pathophysiological hypothesis is proposed, in which the functional interactions of Angiotensin-II type-1 and N-methyl-D-aspartate receptors are of pivotal importance. The whole body of clinical evidence (nature of precipitating events, associations with migraine, gender-based association patterns) was integrated.

[GABAB receptor autoimmune encephalitis presenting as transient epileptic amnesia].

This case was a 50-year-old healthy woman. After repeated transient amnesia, she developed tonic-clonic seizures and was admitted to our hospital. The brain MRI showed FLAIR hyperintensities in the left temporal lobe and EEG showed an epileptic discharge starting from the left temporal region. Based on these findings, we diagnosed temporal lobe epilepsy associated with acute limbic encephalitis. While she experienced recurrent transient amnesia, her cognitive functions were preserved except for her memory. These symptoms and EEG findings were consistent with transient epileptic amnesia (TEA). Acute limbic encephalitis that occurred in a healthy middle-aged woman may be antibody-mediated encephalitis, requiring immediate immunotherapies. In this case, GABAB receptor antibodies in cerebrospinal fluid were found positive. This is the first report showing that TEA was caused by GABAB receptor autoimmune encephalitis.

[Ictal EEG pattern of transient epileptic amnesia in acute phase of non-herpetic limbic encephalitis].

A 60-year-old, right-handed woman was admitted to our hospital for amnesia as the only neurological abnormal findings following the autonomic symptoms and transient episodes of loss of awareness. EEG during the amnesia showed rhythmic alpha activity arising from the left mid-temporal region. Although this ictal activity showed evolution in the frequency and amplitude, the location was limited in the bilateral temporal areas. After the EEG evaluation, her amnesia was resolved immediately, suggesting that her presentation was transient epileptic amnesia (TEA). Meanwhile, given the clinical course and MRI findings (high intensity in the bilateral mesial temporal areas, more on the left), she was diagnosed with non-herpetic limbic encephalitis and treated with steroid and anti-epileptic drugs, leading to the positive outcome. The ictal EEG findings during TEA as the one of the presentation in acute phase of non-herpetic limbic encephalitis may contribute to further investigation of underlying mechanism of TEA.

Long-Term Risk of Stroke After Transient Global Amnesia in Two Prospective Cohorts.

Background and Purpose- Transient global amnesia (TGA) is known as a benign syndrome, but recent data from neuroradiological studies support an ischemic cause in some cases, which might suggest an increased susceptibility to cerebrovascular events. We determined the long-term risk of stroke after a first TGA in 2 independent prospective cohorts. Methods- In 2 independent prospective cohorts of patients with TGA (OXVASC [Oxford Vascular Study], population-based; NU (Northern Umbria) cohort, TGA registry), cardiovascular risk factors and long-term outcomes, including stroke and major cardiovascular events, were identified on follow-up. Cardiovascular risk factors were treated according to primary prevention guidelines. In OXVASC, the age-/sex-adjusted risk of stroke during follow-up was compared with that expected from the rate in the underlying study population. Results- Among 525 patients with TGA (425 NU and 100 OXVASC), mean (SD) age was 65.1 (9.5) years and 42.5% male. Hypertension (58.1%), dyslipidemia (40.4%), and smoking (36.4%) were the most frequent cardiovascular risk factors. The risk of stroke was similar in the 2 cohorts, with a pooled annual risk of 0.6% (95% CI, 0.4-0.9) and a 5-year cumulative risk of 2.7% (1.1-4.3). Moreover, the stroke risk in OXVASC cases was no greater than that expected in the underlying study population (adjusted relative risk=0.73; 0.12-4.54; P=0.74). Conclusions- TGA does not carry an increased risk of stroke, at least when cardiovascular risk factors are treated according to primary prevention guidelines.

Transient global amnesia associated with sildenafil use: report of one case / Amnesia global transitoria asociada al uso de sildenafil: informe de un caso

ABSTRACT A 69 years old male with erectile dysfunction lasting 2 years, took 50 mg of sildenafil for having sex with his wife at about 6 o'clock in the morning. One hour later his wife detected that he had an anterograde memory impairment: this was interpreted as a confusional state. The neurological examination suggested a transient global amnesia (TGA). EEG and cerebral magnetic resonance imaging were non-informative and memory deficits resolved within 24 h. Therefore, a TGA was diagnosed. Since no other trigger was detectable, sildenafil was deemed responsible for its occurrence,

Se reporta el caso de un individuo de sexo masculino de 69 años con disfunción eréctil, que ingiere 50 mg de sildenafil con objetivo de facilitar el mantener relaciones sexuales con su esposa. Una hora después, su esposa nota que su marido presenta una alteración de su memoria anterógrada, lo que fue interpretado como un estado confusional. Evaluado clínicamente su examen neurológico es sugerente de una amnesia transitoria anterógrada. El EEG y las imágenes por resonancia magnética no muestran hallazgos significativos y el déficit de memoria remite dentro de 24 h. en vista de su evolución, se diagnostica una amnesia global transitoria. Como no se identifica otro gatillante, se consideró que el cuadro fue causado por sildenafil..

Transient global amnesia: clinical features and prognostic factors suggesting recurrence / Amnesia global transitoria: características clínicas y factores pronósticos sugestivos de recurrencia

ABSTRACT The risk of recurrence of new amnesia events in patients having previously experienced transient global amnesia (TGA) ranges between 2.9-23.8%. Objective: Our objective was to search for recurrence predictors in TGA patients. Methods: Retrospective analysis to identify recurrence predictors in a cohort of 203 TGA patients from a single center in Buenos Aires, Argentina, diagnosed between January 2011 and March 2017 Clinical features and complementary studies (laboratory results, jugular vein Doppler ultrasound and brain MRI) were analyzed. Comparison between patients with recurrent versus single episode TGA was performed, applying a multivariate logistic regression model. Results: Mean age at presentation was 65 years (20-84); 52% were female. Median time elapsed between symptom onset and ER visit was two hours, with the average episode duration lasting four hours. Mean follow-up was 22 months. Sixty-six percent of patients referred to an identifiable trigger. Jugular reflux was present in 66% of patients; and 22% showed images with hippocampus restriction on diffusion-weighted MRI. Eight percent of patients had TGA recurrence. Patients with recurrent TGA had a more frequent history of migraine than patients without recurrence (37.5% vs. 14%; p = 0.03). None of the other clinical characteristics and complementary studies were predictors of increased risk of recurrence. Conclusions: Patients with migraine may have a higher risk of recurrent TGA. None of the other clinical characteristics evaluated allowed us to predict an increased risk of recurrence. Although the complementary studies allowed us to guide the diagnosis, they did not appear to have a significant impact on the prediction of recurrence risk.

RESUMEN El riesgo de recurrencia de nuevos eventos de amnesia en pacientes que han experimentado previamente Amnesia Global Transitoria (AGT) oscila entre el 2.9-23.8%. Objetivo: Nuestro objetivo fue buscar predictores de recurrencia en pacientes con AGT. Métodos: Análisis retrospectivo de una cohorte de 203 pacientes con AGT de un único centro en Buenos Aires, Argentina, diagnosticados entre enero-2011 y marzo-2017 Se analizaron las características clínicas y los estudios complementarios (laboratorio, Doppler de vena yugular y RM encéfalo). Se comparó el grupo de AGT recurrente versus episodio único, aplicando un modelo de regresión logística multivariada. Resultados: la edad promedio de presentación fue de 65 años (20-84); 52% mujeres. La mediana del tiempo transcurrido entre el inicio de los síntomas y la visita a la sala de emergencia fue de 2 horas, con una duración promedio del episodio de 4 horas. El seguimiento medio fue de 22 meses. 66% de los pacientes tuvieron un desencadenante identificable. El reflujo yugular estuvo presente en el 66% de los pacientes y el 22% mostró imágenes restrictivas en DWI a nivel hipocampal. 8% de los pacientes presentaron recurrencia. Los pacientes con AGT recurrente tuvieron un historial de migraña más frecuente (37.5% vs. 14%; p=0.03). Ninguna de las otras características clínicas y estudios complementarios fueron predictores de mayor riesgo de recurrencia. Conclusiones: los pacientes con migraña pueden tener un mayor riesgo de recurrencia de AGT. Ninguna de las otras características clínicas evaluadas nos permitió predecir un mayor riesgo de recurrencia. Aunque los estudios complementarios nos permitieron orientar el diagnóstico, no pareció tener un impacto significativo en la predicción del riesgo de recurrencia.

Medical Procedure-Related Transient Global Amnesia.

BACKGROUND: Transient global amnesia (TGA) is an interesting clinical syndrome characterized by sudden memory loss for recent events and an inability to retain new memories usually lasting several hours and recovering spontaneously. We conducted a literature search of medical procedure-related TGA and its predisposing conditions. METHODS: We performed PubMed searches using the keyword "transient global amnesia" combined with "procedure," "test," "therapy," or various other individual medical procedures. In addition, we described 2 cases of gastroscopy-related TGA. RESULTS: Eighty-nine patients with medical procedure-related TGA in 49 articles were summarized. The most common procedure was cerebral angiography (n = 45), followed by coronary angiography (n = 10) and general anesthesia (n = 9). After categorization, neurological procedures were most common (n = 46, 51.7%), followed by cardiac (n = 17, 19.1%), anesthetic (n = 11, 12.4%), gastrointestinal (n = 4, 4.5%), and pulmonary (n = 2, 2.2%) procedures. CONCLUSIONS: Diverse cases of medical procedure-related TGA have been reported in the literature. Valsalva-associated activities, emotional stress with anxiety, and acute pain were predisposing conditions. An understanding of medical procedure-related TGA may be important for clinicians who perform such medical procedures.

Adult-onset neuronal intranuclear inclusion disease presented transient global amnesia-a case report.

A 65-year-old man had a transient amnesia for about 3 hours. Similar symptoms appeared three years ago. He did not manifest dementia, cerebellar ataxia and involuntary movements. Peripheral neuropathy was observed by the neurophysiological examinations. Diffusion weighted image showed high intensity signal in the area of the corticomedullary junction of the frontal to parietal lobes and immunohistochemical studies of biopsied skin revealed many intranuclear inclusion bodies. Adult-onset neuronal intranuclear inclusion disease was diagnosed. As there was no similar member in his family, he was a sporadic case. Clinical characteristics of his amnesia was fulfilled with the criteria of transient global amnesia (TGA). The transient disturbance of limbic system was suspected.

Amnésia global transitória: epidemiologia, fisiopatologia, clínica e terapêutica / Global transient amnesia: epidemiology, pathophysiology, clinical features and therapeutics

A amnésia global transitória (AGT) é um quadro súbito de amnésia global, não acompanhada de outros déficits neurológicos, com duração de duas a 24 horas e cuja recuperação se dá espontaneamente. A incidência na população geral está estimada em 5-10 casos/100.000 pessoas/ano. Diferentes mecanismos fisiopatológicos, como fatores vasculares ou epiléticos, têm sido propostos para explicar a AGT, sendo consensual que haja acometimento transitório de regiões do hipocampo e do giro para-hipocampal. Além da amnésia anterógrada acompanhada por amnésia retrógrada, o paciente apresenta desorientação (tempo/espaço), estando preservadas outras habilidades cognitivas, como memória semântica e capacidades visuo-construtivas. Esses déficits tendem a remitir após 24h, sendo o prognóstico favorável na maioria dos casos. O diagnóstico diferencial de AGT é amplo e diversas condições clínicas, como eventos cérebro-vasculares, epilepsias, infecções e intoxicações podem mimetizá-lo, de modo que uma investigação clínica cuidadosa é imperativa. As recorrências não são frequentes nos quadros típicos. A AGT não requer tratamento específico, mas devem ser tratados fatores de risco cardiovascular eventualmente identificados durante a propedêutica de AGT. O clínico deve esclarecer o paciente a respeito do caráter benigno da AGT. Estudos com seguimento longitudinal dos pacientes são necessários para maior compreensão dos mecanismos fisiopatológicos da AGT e para melhor compreensão clínica e neuro- biológica dos déficits cognitivos apresentados por esses pacientes.

Global transient amnesia (GTA) is a clinical syndrome characterized by the sudden onset of anterograde and retrograde amnesia, without permanent neurological deficits, and which presents complete remission spontaneously within 2 to 24 hours. The incidence of GTA in the general population ranges from 5 to 10 cases per 100.000 individuals/ year. Different pathophysiological mechanisms have been proposed for GTA, such as vascular or epileptic factors, and it is consensual that there is transitory involvement of hippocampal and parahippocampal gyri in this condition. In addition to anterograde and retrograde amnesia, GTA patients typically present time-space disorientation, with the preservation of other cognitive abilities, such as semantic memory and visuoconstructive capacities. The differential diagnosis includes stroke, epilepsy, infections and intoxication, and a careful clinical investigation is essential to establish the GTA diagnosis. Recurrence is uncommon in typical cases and, in general, no specific treatment is required. However, clinical investigation of GTA may eventually disclose cardiovascular risk factors; these factors should be treated when identified. GTA is considered a benign condition, with good clinical and cognitive prognostics in most of the cases. More studies are needed to advance the current knowledge on the pathophysiology and on the neural basis of the transitory cognitive impairment observed in GTA.

Transient global amnesia in immediate postoperative period: A diagnostic dilemma.

INTRODUCTION: Transient Global Amnesia (TGA) is short-term inability to form new memories despite otherwise normal neurological function. There is associated anterograde and retrograde amnesia. The memory loss is often accompanied by repetitive questioning and temporal disorientation while higher cognitive functions are preserved. The symptoms usually resolve by 24h. CASE REPORT: We present an interesting case of 31year old female who was planned for robotically assisted right sided pyeloplasty. 30min after emergence from anaesthesia patient was disoriented, with retrograde and anterograde amnesia, but neurological function was intact. Neurologic imaging revealed no abnormality. 36h later patient was able to recall everything. DISCUSSION: The pathogenesis of TGA has more recently been attributed to cerebral venous hypertension resulting from retrograde jugular venous flow. Precipitating events are Valsalva manoeuvre, emotion/stress/pain, Excessive exertion, sexual intercourse and swimming in cold water. CONCLUSION: TGA presents dramatically, it needs to be differentiated from cerebral event. It resolves on its own. But one needs to be aware of existence of such an entity.

Transient global amnesia: a study with Tc-99m ECD SPECT shortly after symptom onset and after recovery.

PURPOSE: Transient global amnesia (TGA) is characterized by sudden loss of memory of recent events, transient inability to retain new information, and retrograde amnesia. We investigated the changes of regional cerebral blood flow in patients with TGA shortly after symptom onset and after recovery using Tc-99m-ethyl cysteinate dimer single-photon emission computed tomography (Tc-99m ECD SPECT) and statistical parametric mapping (SPM) analysis. METHODS: Six right-handed patients with TGA were studied using Tc-99m ECD SPECT shortly after symptom onset and after recovery. As a control group, six healthy individuals were also studied. Images were analyzed using SPM8 using voxel-based analysis to estimate the differences between TGA patients and controls. RESULTS: There was significant hypoperfusion in the left hippocampus, left thalamus, and bilateral cerebellum. In the follow-up SPECT scan, hypoperfusion in hippocampus and thalamus were restored, while hypoperfusion was noted in the temporoparietal region. CONCLUSION: Our results suggest that the underlying mechanism of TGA may be temporary ischemia in the hippocampus and thalamus. There was significant restoration of perfusion in the hippocampus and thalamus after recovery from TGA.

Longitudinal Cerebral Perfusion Change in Transient Global Amnesia Related to Left Posterior Medial Network Disruption.

BACKGROUND: The pathophysiology of transient global amnesia (TGA) is not fully understood. Previous studies using single photon emission computed tomography (SPECT) have reported inconclusive results regarding cerebral perfusion. This study was conducted to identify the patterns of regional cerebral blood flow (rCBF) in TGA patients via longitudinal SPECT analysis. An association between the observed SPECT patterns and a pathophysiological mechanism was considered. METHODS: Based on the TGA registry database of Seoul National University Bundang Hospital, 22 TGA patients were retrospectively identified. The subjects underwent initial Tc-99m-ethyl cysteinate dimer (ECD) SPECT within 4 days of an amnestic event and underwent follow-up scans approximately 6 months later. The difference in ECD uptake between the two scans was measured via voxel-based whole brain analysis, and the quantified ECD uptake was tested using a paired t-test. RESULTS: The TGA patients had significantly decreased cerebral perfusion at the left precuneus (P<0.001, uncorrected) and at the left superior parietal and inferior temporal gyrus according to the voxel-based whole brain analysis (P<0.005, uncorrected). A difference in the quantified ECD uptake between the 2 scans was also found at the left precuneus among the 62 cortical volumes of interest (P = 0.018, Cohen's d = -0.25). CONCLUSION: We identified left hemispheric lateralized hypoperfusion that may be related to posterior medial network disruption. These findings may be a contributing factor to the pathophysiology of TGA.

[Transient global amnesia: A descriptive study of 12 Polynesian patients]. / Ictus amnésique: étude descriptive de 12 patients polynésiens.

INTRODUCTION: According to the criteria of Hodges and Warlow, transient global amnesia is defined by sudden onset of isolated anterograde amnesia of spontaneous resolution within one to twenty-four hours. Its pathophysiological mechanisms are still uncertain. METHODS: In a retrospective study, we have analyzed epidemiological, clinical and MRI data from twelve patients admitted to the only neurological department of French Polynesia for transient global amnesia corresponding to the criteria of Hodges and Warlow between January 2010 and December 2013. RESULTS: The median age of the cohort was 61.5 (53-72), the sex ratio was 1. Ten patients had one or more cardiovascular risk factors, 3 had migraine headaches and 3 had anxiodepressive disorders. Among triggers found, the occurrence during the rest was noted in one case. Retrograde amnesia was observed in 42% of cases, repetitive questioning in 75% of cases, anxious bewilderment in 67% of cases and disorientation in 33% of cases. The median episode duration was 9 hours and the duration of hospitalization was 3 days. Three patients had a recurrence. MRI was abnormal in all patients and showed diffusion-weighted hyperintensities in right (n=8), left (n=3) and bilateral (n=1) hippocampi. CONCLUSION: Epidemiological, clinical and MRI data from our cohort are similar to those from the literature except for the highest prevalence of cardiovascular risk factors and the most frequent right hippocampus involvement. Transient global amnesia occurring exceptionally while sleeping was also observed in one of our patients.

Transient memory impairment and transient global amnesia induced by photodynamic therapy.

Photodynamic therapy (PDT) is a commonly used and effective treatment option for nonmelanoma skin cancer. Apart from local side-effects such as pain, oedema and erythema, no major adverse events occur in the majority of cases. Here we report on five patients who developed memory deficits such as transient global amnesia immediately after PDT for actinic keratosis. All PDT treatments were performed according to standard therapy protocols. The reported patients had a memory gap for the entire procedure, as well as for the consecutive emergency medical care. Other common neurological causes such as stroke or epileptic seizures were excluded. No focal neurological deficits were detectable. The symptoms had a fairly rapid onset following red-light illumination and were reversible without sequelae within 1-24 h. No correlation of the condition and pain during the illumination could be revealed. Magnetic resonance imaging of the brain revealed punctuated lesions in the hippocampus as a potential morphological correlate in one patient. The association between amnestic syndromes and PDT is novel and has not previously been reported. Even though PDT is considered a safe treatment modality, the possibility of neurological adverse events, albeit rare, should be kept in mind.