The concept of akinesia.

The concept of akinesia deserves to be looked at again in the light of recent work on Parkinsonism, particularly those findings which have resulted from the use of L-dopa in Parkinsonian syndromes. Akinesia and bradykinesia are integral parts of such syndromes, at times even constituting their essential element. Akinesia belongs to a group of psychomotor syndromes, the semiology and pathogenesis of which were the subject of numerous discussions at the beginning of this century. As we have pointed out elsewhere, akinesia cannot be defined solely in terms of its own characteristics: it must be understood equally in its paradoxical aspects--"paradoxical kinesia" in post-encephalitic Parkinsonism in particular, and "paradoxical akinesia" in Parkinsonian patients treated with L-dopa.