Age and medication effects on rhythmic responses in ADHD: Possible oscillatory mechanisms?

Hilla Ben-Pazi*, Ruth S. Shalev, Varda Gross-Tsur, Hagai Bergman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

Voluntary motor responses in children with attention-deficit hyperactivity disorder (ADHD) may reflect underlying neuronal oscillatory mechanisms. The aims of this study were: (1) to corroborate the presence of rhythmic motor abnormalities on tapping test in children with attention-deficit hyperactivity disorder, shown in previous studies; (2) to delineate the characteristics of ADHD children demonstrating these rhythmic abnormalities; (3) to assess the impact of methylphenidate (Ritalin) on this abnormal motor phenomenon. The study was designed in a double blind manner. Sixty-four ADHD children aged 6-12 years and 60 matched controls underwent a finger tapping test (1-5 Hz). We measured the abnormal rhythmic tapping with and without methylphenidate treatment in a double blind design. Conventional statistical analysis was used to assess the correlation of the presence of motor abnormality with various clinical characteristics (such as degree of hyperactivity/impulsivity). Fifty-six percent of children with ADHD compared to 8% of controls demonstrated abnormal rhythmic responses at a mean frequency of 3.1 ± 0.9 Hz. These erroneous voluntary movements were more common in children with a greater degree of hyperactivity, in younger children but not significantly altered by methylphenidate treatment. Surprisingly, abnormal rhythmic responses showed less variability than found for responses for which the tapping was adequately paced, suggesting different motor control processes for normal and abnormal paced tapping. We speculate that rhythmic tapping responses reflect abnormal oscillatory mechanisms involved in ADHD, exacerbated in younger children with ADHD and in those in whom the hyperactivity/impulsivity is more pronounced.

Original languageAmerican English
Pages (from-to)412-416
Number of pages5
JournalNeuropsychologia
Volume44
Issue number3
DOIs
StatePublished - 2006

Bibliographical note

Funding Information:
This study was supported by the National Institute for Psychobiology in Israel Founded by the Charles E. Smith family. We thank Asaf Regev and Ayelet Ben-Sasson for statistical analysis and Navah Badihi for research assistance. We would like to thank the children, parents and teachers for their time and effort.

Keywords

  • Finger tapping test
  • Frequency
  • Methylphenidate
  • Motor
  • Voluntary

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