Diadochokinesia

Diadochokinesia or diadochokinesis is the ability to make antagonistic movements in quick succession, alternately bringing a limb into opposite positions, as of flexion and extension or of pronation and supination.^[1] Speech-language pathology defines it as the speed necessary to stop a determined motor impulse and substitute it with its opposite. The relative timing of this kind of movements is also called alternate motion rates (AMR) or sequential motor rates (SMR).^[2]

Loss of ability (dysdiadochokinesia) is characteristic of cerebellar diseases. Many clinical tests may be employed to test for such disturbances.^[3]

• Alternating movements: Patient is told e.g. to pronate and supinate his hands in rapid succession, holding forearms vertically. In cerebellar diseases, the movements are irregular and inaccurate; in case of the pyramidal tract lesion the motion may be slowed or incomplete.
• Stewart-Holmes rebound sign: Patient tries to flex the elbow against applied resistance. When physician's grip is suddenly released, the patient should be able to deter it from rebounding. With cerebellar disease, the forearm may sway in several cycles. The patient may even strike himself if not guarded.
• Number of instrumental techniques can be used to investigate speech motor skills, such as imaging movement transduction and point tracking.^[4][5]

See also

• Dysdiadochokinesia
• Adiadochokinesia

References

1. Taber's Cyclopedic Medical Dictionary (21st ed.). F. A. Davis Company. 2009. p. 635. ISBN 978-0-8036-1559-5.
2. Juste, FS; Rondon, S; Sassi, FC; Ritto, AP; Colalto, CA; Andrade, CR (15 May 2012). "Acoustic analyses of diadochokinesis in fluent and stuttering children". Clinics. 67 (5): 409–414. doi:10.6061/clinics/2012(05)01. PMC 3351255. PMID 22666781.
3. LeBlond, [edited by] Richard F.; Brown, Donald D.; DeGowin, Richard L. DeGowin; illustrated by Elmer; Abel, Jim; Roach, Shawn (2009). DeGowin's diagnostic examination (9th ed.). New York: McGraw-Hill Medical. pp. 697–698. ISBN 978-0-07-164118-0.
4. Walsh, B; Smith, A (Dec 2002). "Articulatory movements in adolescents: evidence for protracted development of speech motor control processes.". Journal of speech, language, and hearing research : JSLHR. 45 (6): 1119–33. PMID 12546482.
5. Smith, A; Kleinow, J (Apr 2000). "Kinematic correlates of speaking rate changes in stuttering and normally fluent adults.". Journal of speech, language, and hearing research : JSLHR. 43 (2): 521–36. PMID 10757701.