RESUMO
The changes in postural tremor of the hand produced by moderate cooling of the muscles of one forearm have been investigated in 16 normal subjects and in 16 patients with essential tremor. In both groups, cooling produced a profound long lasting decrease in tremor level of the ipsilateral hand. In normal subjects, although cooling reduced the tremor size, the EMG of the active muscle clearly increased. Warming the limb in normal subjects produced an increase in tremor level and decrease in EMG. Cooling or warming the limb did not, however, significantly change the peak frequency which was quite stable for each subject. The results of cooling were compared with a brief period of ischaemia, which also reduces tremor size. Local cooling may be a useful manoeuvre for patients with essential tremor, and for others who wish to reduce their tremor temporarily in order to improve dexterity.
Assuntos
Temperatura Corporal , Antebraço/fisiologia , Músculos/fisiologia , Postura , Tremor/diagnóstico , Adulto , Idoso , Circulação Sanguínea , Eletromiografia , Feminino , Lateralidade Funcional , Humanos , Isquemia/fisiopatologia , Masculino , Pessoa de Meia-Idade , Radiocirurgia , Tremor/etiologia , Tremor/fisiopatologiaRESUMO
Postural tremor was recorded from psychiatric patients who had been treated with phenothiazine or butyrophenone neuroleptic drugs. None of the patients had previously been diagnosed as having extrapyramidal dysfunction. A significant number of these patients had abnormally low tremor frequencies. Low frequency tremors are often associated with Parkinson's disease (PD) so that some of these patients may have early signs of drug induced Parkinsonism (DIP). The results indicate that DIP is not necessarily characterised by a bilateral slow frequency tremor, but may initially be similar to idiopathic PD, even though its cause and prognosis are different.
Assuntos
Antipsicóticos/efeitos adversos , Doença de Parkinson Secundária/induzido quimicamente , Adolescente , Adulto , Idoso , Antipsicóticos/administração & dosagem , Butirofenonas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Exame Neurológico/efeitos dos fármacos , Doença de Parkinson Secundária/diagnóstico , Fenotiazinas , Postura , Tremor/induzido quimicamente , Tremor/diagnósticoRESUMO
The cause of essential (low-frequency) tremor is unknown and its relation to physiological (high-frequency) tremor is unclear. We assessed essential tremor in one patient before and after a stereotactic thalamic lesion. The procedure changed the size of the tremor in the right hand but not in the left. Persistence of a low-frequency component suggested that essential tremor was an additional feature superimposed on physiological tremor in this patient. The focus of essential tremor seems to be an autonomous central generator that is independent of physiological tremor mechanisms.
