Letters to the editor

Incidence of transient global amnesia in a Alcoi (Spain) The April 1990 issue of Acta Neurol Scand contains a very interesting paper by Koski & Marttilla about the frequency of transient global amnesia (TGA) in Turku. The authors found an annual TGA incidence rate of 10 per 100,000 population and 32 per 100,000 among those aged 50 years old (1). The rates found are clearly higher than those previously reported by others (2). To evaluate the incidence of first-ever TGA in the sanitary area of Alcoi (Community of Valencia), we have done an analysis of the TGA patients included in the archives of our hospital between June 1986 and June 1990. The area investigated comprised 133,915 people. A more complete description of the whole population of the health area or geographic, climatic, economic and other characteristics have been described elsewhere (3). The criteria for the diagnosis of TGA were previously described (4) and were: 1) transient amnestic attack with no direct relation to cranial trauma or whiplash; 2) evidence given by a witness to the inability to form new memories; 3) repetitive queries; 4) apparently normal behaviour and orientation; 5 ) evidence given by the witness of normal long-term memory; 6) presence of retrograde amnesia at least during the episode; and 7) absence of other neurological signs and symptoms during the event. During the period, 8 men and 8 women fulfilled all the described diagnostic criteria with a mean age of 62.1 years (standard deviation 10.8). TGA incidence data are shown in the table. The duration of the episodes lasted 5 to 30 min in 1 patient, 1 to 2 h in 2, and 2 to 24 h in 13 cases. Cranial CT scan was normal in 8 patients. Abnormalities included cere-

bra1 infarcts in 2 cases, cerebral atrophy in 3, intracranial calcifications in 2 and subaracnoidal hemorrhage in 1. Four patients had a history of migraine, 2 had hypertension and 1 case had previously been treated for encephalitis. The age, sex distribution and duration of the events in our patients were similar to other series (9, but our TGA incidence data indicate that TGA is less common in Alcoi than in Turku. Our experience lets us conclude that we agree that TGA is more common than has usually been proposed, but we are not able to find the highest rates described in Turku. Consequently, our data suggest that the different criteria of ascertainment (6, 7), or the existence of geographic differences in the incidence rates may explain these findings. New studies of the incidence rate of TGA are warranted. References RJ. Transient global amnesia: inci1. KOSKIKJ, MARTILLA dence in an urban population. Acta Neurol Scand 1990: 81: 358-360. 2. MILLERJW, PETERSEN RC, METTEREJ et al. Transient global amnesia: clinical characteristic and prognosis. Neurology 1987: 37: 133-731. J, BOLUMARF, MARTINR et al. Multiple 3. MATIAS-GUIU sclerosis in Spain: an epidemiological study of Alcoy health region, Valencia. Acta Neurol Scand 1990: 80: 479-483. J, COLOMER R, SEGURA A, CODINA A. Cra4. MATIAS-GUIU nial CT scan in transient global amnesia. Acta Neurol Scand 1986: 13: 298-301. JAM. Transient global amnesia: an amnestic TIA. 5. FREDERIKS In: MARKOWITSCH HJ, ed. Transient global amnesia and related disorders. Toronto: Hogrefe & Huber, 1990, 28-47. 6. MATIAS-GUIU J, CODINAA. Transient global amnesia: criteria and classification. Neurology 1986: 36: 441-442. LR. Transient global amnesia. In: VINKEN P, BRUYN I . CAPLAN G, KLAWANS H, eds. Handbook of clinical neurology. Amsterdam: Elsevier, 1985: 205-218.

Table

All people 50 years or older

Annual incidence rate per 100,000 inhabitants

95% Confidence intervals

2.98 3.93

1.50-4.42 1.25-6.25

Matias-Guiu, J. Blanquer, R . Falip, A . Oltra, M , Martin Virgen de Los Lirios Hospital Alicante, Spain

J.

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Incidence of transient global amnesia in a Alcoi (Spain)

Letters to the editor Incidence of transient global amnesia in a Alcoi (Spain) The April 1990 issue of Acta Neurol Scand contains a very interesting...
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