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EEG abnormalities in early and late onset Alzheimer's disease: understanding heterogeneity
  1. Hanneke de Waal1,
  2. Cornelis J Stam2,
  3. Marinus A Blankenstein3,
  4. Yolande A L Pijnenburg1,
  5. Philip Scheltens1,
  6. Wiesje M van der Flier1
  1. 1Alzheimer Centre, Department of Neurology, VU University Medical Centre, Amsterdam, The Netherlands
  2. 2Department of Clinical Neurophysiology, VU University Medical Centre, Amsterdam, The Netherlands
  3. 3Department of Clinical Chemistry, VU University Medical Centre, Amsterdam, The Netherlands
  1. Correspondence to H de Waal, Alzheimercenter VU University Medical Centre, PO Box 7057, 1007 MB Amsterdam, the Netherlands; h.dewaal{at}vumc.nl

Abstract

Objective To compare differences in severity and type of electroencephalography (EEG) abnormalities between early and late onset Alzheimer's disease (AD) and to assess the influence of APOE genotype on this association, in order to understand the biological differences in AD according to age at onset

Method Of 460 probable AD patients and 336 patients with subjective complaints, serving as controls, EEG and APOE genotype were obtained. Subjects were categorised by age into a younger (≤65 years) and an older group (>65 years), based on age at diagnosis. Severity and type of EEG abnormalities were visually assessed. Severity of EEG abnormalities ranged from normal to slightly abnormal to moderately severe. EEG abnormalities were characterised as only focal abnormalities, only diffuse abnormalities or both focal and diffuse abnormalities.

Results Logistic regression revealed that younger AD patients more often had EEG abnormalities, which were more severe, with a predominance of both focal and diffuse abnormalities. In controls, we observed the opposite, as older controls more often had EEG abnormalities than younger controls. Furthermore, APOE ε4 negative AD patients had more severe EEG abnormalities than APOE ε4 positive AD patients, while no such effect was observed in controls. There was no interaction between age at onset and APOE ε4 genotype.

Conclusion Early onset and APOE ε4 negative AD patients present with more severe EEG abnormalities than late onset and APOE ε4 positive AD patients. These results suggest that in younger patients, AD manifests with more prominent functional brain changes.

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Footnotes

  • Linked articles 224030.

  • See Editorial Commentary, p 2

  • Funding The Alzheimer Centre VUmc is supported by Alzheimer Nederland and Stichting VUmc fonds. The clinical database structure was developed with funding from Stichting Dioraphte.

  • Competing interests None.

  • Ethics approval The study was approved by the ethical review board of VU University Medical Centre.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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