Lempel-Ziv complexity in schizophrenia: a MEG study

Clin Neurophysiol. 2011 Nov;122(11):2227-35. doi: 10.1016/j.clinph.2011.04.011. Epub 2011 May 17.

Abstract

Objective: The neurodevelopmental-neurodegenerative debate is a basic issue in the field of the neuropathological basis of schizophrenia (SCH). Neurophysiological techniques have been scarcely involved in such debate, but nonlinear analysis methods may contribute to it.

Methods: Fifteen patients (age range 23-42 years) matching DSM IV-TR criteria for SCH, and 15 sex- and age-matched control subjects (age range 23-42 years) underwent a resting-state magnetoencephalographic evaluation and Lempel-Ziv complexity (LZC) scores were calculated.

Results: Regression analyses indicated that LZC values were strongly dependent on age. Complexity scores increased as a function of age in controls, while SCH patients exhibited a progressive reduction of LZC values. A logistic model including LZC scores, age and the interaction of both variables allowed the classification of patients and controls with high sensitivity and specificity.

Conclusions: Results demonstrated that SCH patients failed to follow the "normal" process of complexity increase as a function of age. In addition, SCH patients exhibited a significant reduction of complexity scores as a function of age, thus paralleling the pattern observed in neurodegenerative diseases.

Significance: Our results support the notion of a progressive defect in SCH, which does not contradict the existence of a basic neurodevelopmental alteration.

Publication types

  • Controlled Clinical Trial

MeSH terms

  • Adult
  • Aging / physiology*
  • Aging / psychology
  • Cerebral Cortex / anatomy & histology
  • Cerebral Cortex / growth & development
  • Cerebral Cortex / physiopathology*
  • Cognition Disorders / diagnosis
  • Cognition Disorders / etiology
  • Cognition Disorders / physiopathology
  • Disease Progression
  • Female
  • Humans
  • Magnetoencephalography / methods*
  • Male
  • Schizophrenia / diagnosis*
  • Schizophrenia / physiopathology*
  • Schizophrenic Psychology*
  • Signal Processing, Computer-Assisted
  • Young Adult