Fronto-temporal lobar degeneration: semantic variant primary progressive aphasia (advanced)

Case contributed by Dr Brad Hayhow

Presentation

Right-handed ex-officer worker initially presenting at age 58 with a 5 year history of progressive memory impairment and word-finding difficulties. Associated loss of social graces and increasingly concrete thinking. Prominent and severe expressive and receptive language impairment at clinical review aged 62.

Patient Data

Age: 60
Gender: Male

Mental State Examination

  • Neatly groomed and casually dressed gentleman wearing spectacles
  • Overtly suggestible and echopraxic, playing air guitar to music coming from adjacent room
  • "Impoverished, effortful and hesitant speech with marked word-finding and naming difficulties and frequent semantic paraphasias
  • What is mood?"
  • Irritable affect
  • No evidence of hallucinations

Neuropsychology testing:

Strengths: performs within expected premorbid limits on hands-on, performance-based, perceptual-based skills in the domains of problem solving, visual reasoning and visuo-spatial reconstruction.

Weaknesses: severe impairment of expressive and receptive language skills with significant and severe loss of conceptual semantic word meaning. Severely impaired information processing speed.

No evidence of classic executive function impairment.

Findings

Severe volume loss involving the anterior temporal lobes and mesial temporal structures, including hippocampal formations and amygdala, is again demonstrated and unaltered, with marked ex-vacuo dilation of the temporal horns. Pronounced involvement of the superior temporal gyri and presence of gliosis are features favouring frontotemporal dementia over Alzheimer's disease. Moderate out of keeping volume loss involving the frontal lobes is also unchanged. Scattered white matter foci of T2 hyperintensity are consistent with chronic microvascular ischaemia, mild for age. No diffusion restriction or parenchymal susceptibility artefact. Unfortunately perfusion studies are severely degraded by artefact and hence are non contributory.

Conclusion

Frontotemporal atrophy, with marked temporal predominance. Appearance is more consistent with frontotemporal dementia than Alzheimer's disease.

99mTc HMPAO SPECT scan demonstrating severe bilateral temporal hypoperfusion with a predilection for the left as well as moderate bilateral parietal and hypoperfusion. Incidental note is made of mildly decreased cingulate activity, but overall the findings favour a differential diagnosis of a fronto-temporal dementia.

Case Discussion

This patient initially presented with symtoms suggestive of a behavioural variant fronto-temporal dementia, although word finding difficulty was his earliest clinical manifestation and a language-variant fronto-temporal dementia was considered within the differential diagnosis.

Over a follow-up period of 4 years, expressive and receptive language impairment emerged as the dominant phenotype and source of occupational dysfunction. A formal diagnosis of semantic demantia was strongly supported by neuropsychological testing, with clear asymmetric fronto-temporal lobar degeneration on both structural and functional neuroimaging.

This case illustrates the potential for symptom cross-over between different FTLD variants, especially early in the course of illness, with a final diagnosis emerging only in the setting of longitudinal multidisciplinary assessment.

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Case Information

rID: 22360
Case created: 27th Mar 2013
Last edited: 20th Feb 2016
Inclusion in quiz mode: Included

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