Hemiparkinsonism due to a pontomesencephalic cavernoma: improvement after resection. Case report

Localizing parkinsonism based on focal brain lesions

Bradykinesia, rigidity, and tremor frequently co-occur, a clinical syndrome known as parkinsonism. Because this syndrome is commonly seen in Parkinson's disease, symptoms are often attributed to cell loss in the substantia nigra. However, parkinsonism occurs in several other neurological disorders and often fails to correlate with nigrostriatal pathology, raising the question of which brain region(s) cause this syndrome. Here, we studied cases of new-onset parkinsonism following focal brain lesions. We identified 29 cases, only 31% of which hit the substantia nigra. Lesions were located in a variety of different cortical and subcortical locations. To determine whether these heterogeneous lesion locations were part of a common brain network, we leveraged the human brain connectome and a recently validated technique termed lesion network mapping. Lesion locations causing parkinsonism were functionally connected to a common network of regions including the midbrain, basal ganglia, cingulate cortex, and cerebellum. The most sensitive and specific connectivity was to the claustrum. This lesion connectivity pattern matched atrophy patterns seen in Parkinson's disease, progressive supranuclear palsy, and multiple system atrophy, suggesting a shared neuroanatomical substrate for parkinsonism. Lesion connectivity also predicted medication response and matched the pattern of effective deep brain stimulation, suggesting relevance as a treatment target. Our results, based on causal brain lesions, lend insight into the localization of parkinsonism, one of the most common syndromes in neurology. Because many patients with parkinsonism fail to respond to dopaminergic medication, these results may aid the development of alternative treatments.10.1093/brain/awy161_video1awy161media15815555971001.

Headache and Tremor: Co-occurrences and Possible Associations

BACKGROUND

Tremor and headache are two of the most prevalent neurological conditions. This review addresses possible associations between various types of tremor and headache, and provides a differential diagnosis for patients presenting with both tremor and headache.

METHODS

Data were identified by searching MEDLINE in February 2015, with the terms "tremor" and terms representing the primary headache syndromes.

RESULTS

Evidence for an association between migraine and essential tremor is conflicting. Other primary headaches are not associated with tremor. Conditions that may present with both tremor and headache include cervical dystonia, infectious diseases, hydrocephalus, spontaneous cerebrospinal fluid leaks, space-occupying lesions, and metabolic disease. Furthermore, both can be seen as a side effect of medication and in the use of recreational drugs.

DISCUSSION

No clear association between primary headaches and tremor has been found. Many conditions may feature both headache and tremor, but rarely as core clinical symptoms at presentation.

Neuropsychological deficits associated with destruction of the right nigrostriatal pathway

Hemiparkinsonism secondary to a vascular mesencephalic lesion is infrequent; these patients offer an exceptional opportunity to study neuropsychological alterations attributable to unilateral dopaminergic denervation, shedding light on the pathophysiology of cognitive disorders in early-stage idiopathic Parkinson's disease (PD). From the investigation of our case, we conclude that destruction of the right nigrostriatal pathway is accompanied by deficits in executive functioning and verbal/visual memory similar to those observed in many patients with early-stage idiopathic PD. The more complex neuropsychological dysfunction developed by other PD patients must therefore be related to the additional involvement of other brain structures.