Knee jerk responses in infants at high risk for cerebral palsy: an observational EMG study

Elisa G. Hamer, Linze J. Dijkstra, Siebrigje J. Hooijsma, Inge Zijdewind, Mijna Hadders-Algra*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

8 Citations (Scopus)

Abstract

BACKGROUND: Following our clinical observation of tonic responses in response to the knee jerk in infants at very high risk for cerebral palsy (VHR infants), we systematically studied tonic responses, clonus, and reflex irradiation. We questioned (i) whether these responses occurred more often in VHR infants than in typically developing (TD) infants, and (ii) whether they were associated with abnormal general movement quality.

METHODS:Twenty-four VHR and 26 TD infants were assessed around 3 mo corrected age. Surface electromyograms of leg, trunk, neck, and arm muscles were recorded while eliciting the knee jerk. All assessments were video-recorded.

RESULTS:VHR infants more often than TD infants showed tonic responses in the ipsilateral quadriceps and hamstring (Mann Whitney U; P = 0.0005 and P = 0.0009), clonus (Chi-square; P = 0.0005) and phasic responses in the contralateral quadriceps and hamstring (Mann-Whitney U; P = 0.002 and P = 0.0003, respectively). Widespread reflex irradiation occurred in VHR and TD infants. Definitely abnormal general movements and stiff movements were associated with tonic responses (Mann Whitney U; P = 0.0005, P = 0.007, respectively) and clonus (Mann-Whitney U; P = 0.003 and P = 0.0005) in the ipsilateral quadriceps.

CONCLUSION: Similar to clonus, tonic responses may be regarded as a marker of a loss of supraspinal control. Reflex irradiation primarily a neurodevelopmental phenomenon of early ontogeny.

Original languageEnglish
Pages (from-to)363-370
Number of pages8
JournalPediatric Research
Volume80
Issue number3
DOIs
Publication statusPublished - Sept-2016

Keywords

  • ABNORMAL GENERAL MOVEMENTS
  • PHASIC STRETCH REFLEX
  • RECIPROCAL EXCITATION
  • BICEPS-BRACHII
  • CHILDREN
  • INTERVENTION
  • SPASTICITY
  • CURRENTS
  • MUSCLES

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