Do these two expressions have the same meaning?

1- Tetanic contractions in the skeletal muscles 2- Rythmic shaking of the hands

(These two expressions are supposed to be two symptoms of Parkinson’s disease ,however I am told that this is repetition)

  • $\begingroup$ I think both for the purpose of convincing your instructors, and for the purpose of asking a well-researched SE question, it would be better if you started with trying to make your case. Why do you think they should be considered distinct? What have you learned about these symptoms yourself? Telling a test grader "these should be considered distinct!" is less convincing than "these should be considered distinct because A, B, C, D". I worry that giving you an answer here that you use to debate a test grade is similar to doing homework for you. $\endgroup$
    – Bryan Krause
    Commented Jul 13, 2020 at 16:56
  • $\begingroup$ I really appreciate your point of view and admit I have to do better research . But I wish you would at least answer this question : do you consider them distinct? $\endgroup$
    – user261947
    Commented Jul 13, 2020 at 20:24
  • $\begingroup$ No, I won't, for the reasons I've stated. $\endgroup$
    – Bryan Krause
    Commented Jul 13, 2020 at 20:29

1 Answer 1


Tetanic contractions and tremor are different phenomena.

Tetanic contraction (or tetanus) refers to sustained contraction of a muscle subjected to high-frequency stimulation. With this high frequency, a new contraction begins before the previous one has ended. Thus the contractions get 'summed up'. You could see this interesting video for a demonstration.

Tremor is an involuntary shivering movement which is caused by alternating contractions of opposing muscle groups. The causes are many, ranging from physiologic tremor to degenerative disorders of the nervous system (such as Parkinson disease).

Note that tetanic contractions are not a symptom of Parkinson disease. In fact they are not a symptom of anything at all, inasmuch as they are a physiological property of isolated muscle. Tremor, on the other hand, is a phenomenon seen in muscle groups, and is one of the core symptoms of Parkinson disease.

  • $\begingroup$ What about “rythmic muscle contractions” ? As it is stated here (g.co/kgs/Pvd27p) as a symptom. $\endgroup$
    – user261947
    Commented Jul 17, 2020 at 18:11
  • $\begingroup$ @user261947 The Google page is probably referring to myoclonus, which is sometimes seen in Parkinson disease. $\endgroup$
    – Adhish
    Commented Jul 17, 2020 at 19:08

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