Françoise Coyette

Acquisition of a novel vocabulary in an amnesic patient

This study explored the ability of a severe amnesic patient (AC) to acquire new vocabulary words. We compared AC’s knowledge of words entered into the French lexicon during three different periods: before 1920, between 1965 and 1985, and after 1986 (i.e. after the onset of his amnesia). AC’s knowledge was assessed by asking him to give, for each word, its definition (word-definition task), the general domain to which the word belonged (‘domain’ task), and to generate a sentence containing the word (sentence-generation task). Finally, we administered a recognition task in which AC had to select, for each word, its correct definition amongst four definitions. For all of these tasks, the results showed that AC’s performance was similar to that of four control subjects matched for age, education, and profession. In particular, there was no difference with regard to AC’s knowledge of words entered into the language after the onset of his amnesia. Therefore, these results indicate that, despite his profound amnesia, AC was able to learn normally new vocabulary words. More generally, they confirm that, at least is some cases, semantic learning can be spared in amnesia.

A case of long-lasting but reversible isolated amnesia of unknown aetiology

We report the case of a 64-year-old man with an acute isolated and prolonged transient amnesic state, The underlying aetiology remained obscure, Brain magnetic resonance examination demonstrated only non-specific slight and transitory signal intensity abnormalities within the left hippocampus on TP-weighted images, Electroencephalographic studies showed repetitive periodical and prolonged bursts of rhythmic theta activity, originating from the left fronto-temporal region, but no typical epileptiform discharges, As an epileptic origin could not be excluded, anti-epileptic treatment was administered. Subsequently, electroencephalographic abnormalities disappeared completely after a few days, On follow-up, repetitive clinical and neuropsychological comprehensive evaluations showed that the mnesic capacities improved slowly and gradually. The gradual improvement concerned time and place orientation first of all and was followed thereafter by improvement of explicit memory and the capacity to learn new information. Clinically, at this stage, the patient appeared appropriately orientated, according to the medical staff and his family, although memory tests remained abnormal. The memory deficit lasted similar to 3 months but was followed by complete recovery. In our discussion, we consider possible aetiologies for transient amnesia with emphasis on an epileptic as opposed to a vascular aetiology by focal hippocampal ischaemia.