A blacksmith, aged seventeen years, already treated three times for recurrent chorea, suffered from slow contractions of the shoulder muscles, involving the elevators and internal and external rotators successively, and accompanied by movements of the head and arm, and by twitches of the quadriceps. Nothing seemed to have any influence over these movements except sleep. The faradic excitability of the shoulder muscles was augmented, the galvanic excitability diminished. Application of the constant current to the head and back sufficed to effect a cure in three weeks.
Marina proposes the term athetotic myospasm for these incessant slow alternating contractions, impulsive myospasm being employed to signify convulsive movements of more than one muscular group, purposive yet irresistible, as in tic and chorea major. Simple myospasm consists of single twitches in individual muscles, recalling those produced by electrical excitation. If several muscles are implicated, the condition is one of multiple myospasm or myoclonus.
TICS AND TREMORS
All tremors, whether they occur during muscular repose or muscular activity, are distinguished by the relative restriction of their range and the regularity of their time. The tremors of paralysis agitans, disseminated sclerosis, senility, toxæmia, hysteria, ex-ophthalmic goitre, etc., are not liable to be mistaken for tic.
It is true, of course, that tremor is sometimes combined with choreiform or athetotic movements in patients with psychical stigmata.[190] A proposal, too, has been made to unite hereditary and functional tremor and to describe them as a tremor neurosis.[191]
However simple be the diagnosis between tremor and tic, it is worth while to note in passing the etiology they may have in common. In a case recorded by van Gehuchten an intention tremor of the right arm co-existed with a tic of the right sternomastoid.
A sudden twitch of the whole body Letulle particularises as a "tic of starting," and Noir too thinks that a start of this nature may constitute a tic, but we are inclined to consider it a generalised reflex.
TICS AND PROFESSIONAL CRAMPS
We have already had occasion to enlarge on the distinguishing features of professional or occupation cramps, spasms, or neuroses. Writers, pianists, violinists, flutists, dressmakers, telegraphists, watchmakers, milkers, knackers, blacksmiths, shoemakers, tailors, dancers, embroiderers, barbers, etc., etc., are all liable to suffer from occupation cramps. In every case the condition is one of inability to perform the professional movement, and that alone.
Grasset proposes to separate intra-professional from post-professional spasm, the former consisting in the impossibility of making the necessary professional movements, the latter in the involuntary over-reproduction of the familiar act. Properly speaking, the post-professional spasm is a tic.