COGNITIVE NEUROPSYCHOLOGY: CASE STUDIES ON MEMORY

CLIVE WEARING

Clive Wearing was a professional musician who developed herpes simplex encephalitis in 1985, causing extensive damage to the hippocampus and surrounding medial temporal structures, alongside frontal lobe involvement. This resulted in one of the most severe documented cases of amnesia. He presents with profound anterograde amnesia, meaning he cannot form new long-term memories, with awareness lasting only a few seconds before resetting. He also shows extensive retrograde amnesia, having lost the majority of his autobiographical past, although fragments of emotional memory remain, most notably his attachment to his wife.

Despite this, his procedural memory remains intact. He can still play the piano and conduct music with fluency, demonstrating that motor and skill-based memory operate independently from episodic and semantic systems. In daily life, he repeatedly experiences the sensation of “waking up” for the first time, requiring constant care and supervision. His case provides strong evidence that the hippocampus is essential for consolidating short-term memories into long-term memory, while also demonstrating that long-term memory is not a single unitary system.

H.M. (HENRY MOLAISON)

Henry Molaison underwent bilateral removal of the medial temporal lobes in 1953 as a treatment for severe epilepsy. This included significant portions of the hippocampus. While the surgery successfully reduced seizures, it resulted in a profound and permanent memory disorder. H.M. exhibited severe anterograde amnesia, being unable to transfer information from short-term to long-term memory. He could retain information briefly, but once attention shifted, the information was lost. He also displayed temporally graded retrograde amnesia, losing memories from the years immediately prior to surgery, while earlier childhood memories remained relatively intact.

Crucially, his procedural memory was preserved. He learned new motor tasks, such as mirror tracing, showing improvement over time despite having no conscious recollection of practising them. In everyday functioning, he was unable to live independently, frequently repeating conversations and lacking continuity of experience. His case provided decisive evidence for the role of the hippocampus in memory consolidation and established a distinction between impaired declarative memory and intact procedural memory.

K.F.

K.F. suffered brain damage following a motorcycle accident, affecting the left parietal and occipital regions. Unlike Clive Wearing and H.M., his impairment was not centred on long-term memory but on short-term memory, particularly for verbal information. His digit span was severely reduced to around one or two items, indicating a marked deficit in verbal short-term storage. However, his visual-spatial short-term memory remained relatively preserved, suggesting that short-term memory is not a single system but composed of distinct subsystems.

Importantly, his long-term memory was intact. He could form and retain new long-term memories, directly contradicting the assumption of the Multi-Store Model that information must pass through a unitary short-term store before entering long-term memory. In daily life, this meant he could function more independently than in the other two cases, although he experienced clear difficulties with verbal processing. His case provided key support for the Working Memory Model, particularly the distinction between the phonological loop and the visuospatial sketchpad.

SYNTHESIS AND THEORETICAL SIGNIFICANCE OF AMNESIA CASE STUDIES TO MEMORY MODELS

Taken together, these cases demonstrate that memory is not a single system but a set of functionally and neurologically distinct processes. Clive Wearing and H.M. show that damage to the hippocampus disrupts the formation of new declarative memories while leaving procedural memory intact, supporting the existence of multiple long-term memory systems. K.F. challenges the idea of a single short-term store and provides evidence for separate verbal and visual subsystems within working memory.

Collectively, these cases dismantle the simplicity of the Multi-Store Model and support more complex, multi-component accounts of memory. They show that different brain regions underpin different types of memory, and that dissociations between these systems can be observed following localised brain damage