Fronto-temporal lobar degeneration - semantic variant

Case contributed by Dr Brad Hayhow


55 year old married engineer presenting with 5 year history of progressive cognitive decline and loss of social and occupational function particularly due to progressive deterioration in language function.

Patient Data

Age: 55
Gender: Male

 There is severe temporal lobe atrophy, somewhat worse on the left side. The hippocampi are also affected but not disproportionately so. Prominence of  the left Sylvian fissure is mild, and attributed to the temporal atrophy. There is also mild biparietal atrophy, without significant frontal lobe atrophy. Apparent volume loss of the posterior aspect of the corpus callosum is more pronounced than usually seen from vascular indentation alone. The volume of the posterior fossa structures is preserved. A mildly prominent cisterna magna is noted - a normal variant. There is no  hydrocephalus. No abnormal signal, diffusion restriction or magnetic susceptibility is seen.

Cognitive Examination


Bedside Cognitive Profile (NUCOG)

Attention 12/20
Visuoconstructional: 16/20
Memory: 17.5/20
Executive: 11.5/20
Language: 14/20

Total: 71/100


Nuclear medicine

99mTc HMPAO SPECT study with Neurostat analysis demonstrating decreased cerebral perfusion with a predilection for the left anterior temporal lobe

Case Discussion

This patient's primary presenting complaint was progressive deterioration in language function, most specifically relating to semantic knowledge. Striking deficits of recognition, naming and abstraction on bedside cognitive examination with fluent but empty speech, word approximations and anosognosia on mental state examination. Otherwise healthy and well with no personal or family history of medical or psychiatric illness.

A language-variant frontotemporal dementia (primary progressive aphasia) was suspected.

Structural neuroimaging demonstrated marked asymmetric temporal lobe atrophy more promininently affecting the left side - an impression that correlated to asymmetric hypometabolism on functional neuroimaging. The pathological diagnosis was frontotemporal lobar degerenation.

Clinical neuropsychology further resolved the pathological diagnosis to semantic dementia on account of preserved fluency of speech and intact repetion, but marked impairment of semantic knowledge and recognition.

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