Islands of memory in H.M. and other patients with global episodic amnesia: a mini review.

We reviewed the performance of global episodic amnesic patient H.M. Although he was affected by severe anterograde and retrograde amnesia (i.e. global amnesia), he occasionally showed some "islands" of residual intact memory. Therefore, we also searched for the presence of islands of memory in other global amnesic patients with the aim of comparing their performance with that of H.M. We sustain that islands of memory might be guided by residual brain structures and memory mechanisms that are not affected by lesions causing global episodic amnesia. Finally, we considered some possible cues for the treatment of amnesia guided by the presence of islands of memory.