This 71-year-old right-handed retired medical secretary, LC, presented with a seven-year history of cognitive decline led by progressive difficulty recognising familiar faces. More recently she had been unable to recognise even close friends and relatives and increasingly relied on other cues to their personal identity (e.g., the type of car they drove). She had also experienced difficulty recognising voices over the telephone. Word finding difficulties were an early feature and she struggled in particular to retrieve personal and brand names. Increasingly she seemed unable to understand how to use everyday household items or to comprehend environmental sounds. Her family had noted an insidious change in her personality and social behaviour beginning around three years after the onset of prosopagnosia and characterised by development of a sweet tooth, reduced empathy, loss of humour and social sensitivity, and increasing self-centredness, with obsessionality around time-keeping, picture puzzles, and music. There was no history of topographical disorientation. There was a past history of severe claustrophobia with previous psychiatric contact but no other significant past personal or family history.
Neuropsychological assessment (summarised in Table 1) corroborated the clinical impression: LC showed deficits of famous face recognition and visual object identification, anomia, and reduced single word comprehension, but her speech was fluent and normally constructed and there was relative preservation of her mnestic, perceptual and executive functions. The general neurological examination was unremarkable. Brain MRI (Figure 1) showed selective atrophy predominantly affecting the anteroinferior and mesial temporal lobes, more marked in the right hemisphere, with less marked atrophy of perisylvian cortices bilaterally. Based on LC's characteristic neuropsychological and neuroanatomical phenotype, a clinical diagnosis of SemD presenting with progressive prosopagnosia was made. This clinical diagnosis was additionally in line with current consensus criteria for the semantic variant of progressive aphasia, acknowledging that a minority of patients in this group do present with prominent difficulties with person recognition.
A noteworthy feature of LC's history was striking attenuation of her previously disabling, longstanding claustrophobia following the onset of cognitive decline. She had been diagnosed by a psychiatrist with claustrophobia in her mid-twenties, and this had remained a significant issue throughout her adult life. Even in childhood, she had disliked being in crowded places such as the school chapel, and in her late teens and early twenties she exhibited mounting anxiety when in confined spaces including lifts, trains, aeroplanes, and other situations with no obvious route of escape. She would develop full-blown panic symptoms with sustained exposure to such situations and avoided them wherever possible, sometimes at the cost of considerable inconvenience (e.g., driving many kilometres out of her way to avoid road tunnels or planning vacations around her fear). There had been no suggestion of a generalised anxiety disorder nor any history of other phobic responses. Her family reported that LC's claustrophobia settled within several years of onset of her cognitive symptoms: she would, for example, now travel willingly on the London Underground and enter crowded lifts when accessing the platforms. A compelling illustration occurred some six years following symptom onset, when she agreed to have a brain MRI and underwent the procedure with no evidence of distress. Indeed, her family remarked that loss of her claustrophobia was the one positive outcome of LC's SemD diagnosis.
On specific enquiry, there was the suggestion of a more general alteration in LC's emotional responses. In earlier life she had been prone to fairly regular vociferous, angry outbursts; these had abated following the onset of cognitive decline. In addition, she now failed to react to situations likely to have provoked disgust premorbidly (e.g., leaving her washing machine filled with stagnant water and accumulating cartons of mouldy food in her house). In contrast to this reduction in certain strong premorbid emotional responses, LC had developed a craving for music (musicophilia), repeatedly requesting to hear the same repertoire of songs derived from Hollywood musicals. She evidently derived considerable pleasure from these songs and, before her family intervened, would stay up late into the night listening to them.