Dowse and Kesteven found degeneration of the nerve-cells of the anterior pyramids, changes in the olivary body, nucleus of the ninth nerve, laminæ and corpus dentatum of the cerebellum and of the anterior cornua of the spinal cord. Also cortical sclerosis of the right lateral column of the cord and miliary changes in the white matter of the corpus striatum and hemispheres.3
3 Ross, Diseases of the Nervous System, vol. ii. p. 797.
In this disease, as in chorea, there must be two classes of cases—those in which there is no lesion to be discovered after death, and others in which there are changes throughout the brain and spinal cord more or less widespread. The cases in which the disease comes on suddenly from some moral shock probably belong to the former class; while in cases which have come on gradually during senility one would expect to find organic changes in the nervous system. Ross4 suggests that the cause of the tremor is probably a diminution in the conductivity of the fibres of the pyramidal tract, which prevents impulses from the cortex reaching the muscles in sufficiently close proximity to produce a continuous contraction. This, however, does not explain the cause of the tremor in the cases where it began suddenly from fright.
4 Op. cit., p. 798.
DIAGNOSIS.—The only diseases with which paralysis agitans may be confounded are disseminated sclerosis, senile tremor, and chorea in the aged. From senile tremor it may be distinguished from the fact that it begins before old age—that the tremor is more excessive and the gait and facial expression are distinctive. Chorea in old persons resembles paralysis agitans, but is not progressive, the tremor is not lessened as a rule by voluntary effort, and the peculiar gait and expression of the face are wanting.
There are many points of difference between paralysis agitans and disseminated sclerosis, as can be seen below:
| PARALYSIS AGITANS. | DISSEMINATED SCLEROSIS. |
| Tremor ceases on voluntary effort, or is not increased by it. | Tremor induced by muscular effort, and ceases during repose. |
| Tremor regular and fine. | Coarse tremor, becoming more so during voluntary effort. |
| Face expressionless; tremor of face rare. | Facial muscles affected; nystagmus frequent. |
| No tremor of head. | Tremor of head generally present. |
| Belongs to advanced age. | Usually comes on before middle age. |
| Propulsion (festination) and retrogression. | Staggering walk. |
TREATMENT.—The results of treatment are not encouraging. Cases have been reported in which cures were effected, but it is doubtful if they were true instances of paralysis agitans. Hyoscyamus and conium have been given with temporary relief to the tremor. Trousseau recommends strychnia, but Charcot declares that it aggravated the cases in which he gave it. Hammond advises the use of galvanism, at the same time giving strychnia or phosphorus. I have seen one case in which decided relief was obtained from arsenic hypodermically, and another in which the patient was benefited for a long time while taking small doses of strychnia combined with iron and quinine, and at the same time static electricity was applied.