Short-term Memory Impairment
There is a small group of patients who suffer from an extremely intense amnesia, and yet who do not appear to exhibit any other evidence of general intellectual impairment. Though uncommon, such patients are of great interest because they enable us to distinguish certain features of the normal and amnesiac memories.
Patients of this kind can appear quite normal when you first meet them. Their speech and manners are quite conventional, and they are normally able to discuss memories of childhood without difficulty. Some appear quite conscious of their memory difficulties; others less so. If they are, they have a tendency to look for ways to conceal it.[*]
So what aspects of an amnesiac’s long-term memory remain undamaged? Semantic recall can be quite normal: a ‘pop-quiz’ on geography, politics, and other aspects of general knowledge may leave them with quite a respectable score. Perceptual–motor skills can also be attained at a normal rate, both the learning of new processes, and the retention of information after an interval. One patient, a writer, was able to compose a poem and to recite it again a few days later. He was, however, quite unable to recall writing the poem, and quite curious about its details. It was as if it came, he commented, “from somewhere outside.”
This, it should be said, is fairly typical. He had no memory of the notebook in which he had written it, or even his own pen, pencil and rubber.[+] He could use them when he had to, though.
[The Home Encyclopaedia of Human Psychology, ed. G. O’Bannon, p.145]
appears entirely normal / semantic memory normal / motor skills normal / perceptual skills normal
may – or may not – be aware of his/her problem