Treatment of Essential Tremor with Long-Chain Alcohols: Still Experimental or Ready for Prime Time? PMC

This means sodium oxybate could only serve for temporary improvement rather than long-term control. In addition, the best effect of the drug was observed in patients who reported improvement of symptoms with small doses of alcohol. These side effects will not only limit the practical use of sodium oxybate but also bring up safety issues.

These characteristics make it nearly impossible for ethanol to serve as long-term control or modulation of the frequency of paroxysms. Furthermore, the ameliorative effects of ethanol may lead to alcoholism especially in those symptomatic patients. As reported in most cases, ethanol of small doses could achieve the best therapeutic effects on patients of ethanol-responsive movement disorders. However, to maintain the same treatment effects, repeated doses are necessary and dose of ethanol increases over time (18). With increasing frequency and rising doses due to tolerance, consumption of ethanol can cause irreversible damage to brains, livers, and other organs (93).

Alcoholism in essential tremor

When ingested orally, it could be quickly absorbed and cross the blood–brain barrier, converted into GHB within the brain (97). It is proved to be an agonist of most GABAB receptors as well (98), which also suggests that it might deliver a similar effect to ethanol. Low-voltage-activated (LVA) calcium (Ca) channels, known as T-type Ca2+ channels, belong to voltage-gated Ca2+ channels with high-voltage-activated (HVA) Ca2+ channels and intermediate-voltage-activated (IVA) Ca2+ channels. Normally, the opening of HVA Ca2+ channels needs a large membrane depolarization, while a weak depolarization near the resting membrane potential could trigger the LVA Ca2+ channels, with IVA in between. Part of LVA Ca2+ channels stay inactivated under normal circumstances (70) (Figure 1).

Finally, a single patient with PHM demonstrated transient increased DWI signal in the cerebellum and thalami, and these signal abnormalities remitted as the patient’s myoclonus subsided [71]. Taken together, these studies in animal and man of coeliac, EPM1 and PHM demonstrate a central role of the cerebellum and Purkinje cells in the generation of myoclonus. Impairment of glutamate pathways, especially different glutamatergic receptors, contributes to the onset of ERMDs such as ET and MD (78). One candidate alternation is the glutamate transporter mainly located in astrocytes, excitatory amino acid transporter 2 (EAAT2). These receptors uptake glutamate into astrocytes to regulate the concentration of glutamate in the extracellular space (Figure 1).

Benefits and risks of pharmacological treatments for ET

Pedrosa demonstrated that the effect of EtOH on ET tremor is due to normalization of cerebellar activation [78]. We propose that the improvement of varied hyperkinetic movement disorders with modest doses of EtOH or GHB does
derive from a simple pharmacologic effect on the GABA-A, GABA-B or GHB receptors. Instead, we propose that
modest alcohol and essential tremor doses of GHB or EtOH possess a specific and novel ability to normalize pathologic hypermetabolism of the cerebellar Purkinje cells and deep cerebellar nuclei. We further propose that
Purkinje cell dysfunction
(either aberrant activation or abnormal synchronous firing)
is the unifying feature linking these varied hyperkinetic disorders.

Botulinum toxin type A injection and alprazolam were found possibly useful with less quality evidence or conflicting results in different studies [38]. To date, among all the definite LVA Ca2+ channel blockers, only ethosuximide and zonisamide were reported to have effects on animal models (74, 106, 107), but little clinical efficacy was found in ethosuximide (108). GABAB receptors (GABABRs), belonging to G protein-coupled receptors, perform different functions according to their location. When located presynaptically, activated GABABRs prevent the release of neurotransmitters like GABA and glutamate. Postsynaptic GABABRs, however, could induce hyperpolarization and slow inhibitory postsynaptic potentials (IPSP) and suppress glutamate receptors as well.

Atenolol vs. propranolol in ET. A controlled, quantitative study

Myoclonus-dystonia being the second common disease in ERMDs, ~76.9% of reported patients of myoclonus-dystonia (MD) were responsive to ethanol (31). Neurophysiological (32), structural (33), functional (34), and metabolic (35) studies also support the cerebellum as the subcortical generator underlying motor symptoms in MD. Two post-mortem studies of coeliac disease patients with cortical myoclonus have demonstrated selective loss of Purkinje cells, illustrating that isolated cerebellar pathology can generate cortical myoclonus [62,63]. In EPM-1 (Unverricht-Lundborg disease), another disorder with prominent cortical myoclonus and EtOH-response, a post-mortem study showed a similar loss of Purkinje cells with involvement of the dentate nucleus [64,65]. Many patients with EPM1 do not appear to have cerebellar atrophy on routine MRI imaging, but an MRI/MRS study of a cohort of patients demonstrated mild atrophy of cerebellar hemispheres, medulla and basis pontis [66]. Cystatin B, the protein affected by EPM1, is selectively expressed in Purkinje cells and some molecular layer neurons in the developing and adult rat [67].

However, both drugs could bring up various irreversible adverse effects soon after regular intake, and longer-term survey reveals that approximately half of patients would discontinue consumption eventually due to tolerance or side effects. Such condition is possibly because of differences between the lesion locations and acting sites of these drugs. Recent clinical trials, as a result, focused more on relatively safe, efficient, concentric drugs. Currently available and recommended pharmacotherapies for ET are often limited by suboptimal treatment effects, frequent adverse effects, and drug interactions. Here, we review the literature on the first clinical trials on 1-octanol and its metabolite octanoic acid (OA) for the treatment of ET. We examined 100 alcoholics who had had no alcohol for more than 21 days, 100 controls, and 50 patients with essential tremor.

The final patient was afflicted with predominant axial jerks triggered by actions such as pouring. In a safety analysis of MRg-FUS thalamotomy (186 patients reported in 5 studies with variable follow-up duration), a total rate of 1.6% procedure-related serious adverse events was reported. Milder side effects varied between 9 and 49% and were mostly sensory and gait disturbances, transient or mild (79%) or moderate causing some impact in daily living (20%). Unilateral MRIgFUS thalamotomy had been shown to be safe from a cognitive standpoint.

Deja una respuesta

Tu dirección de correo electrónico no será publicada. Los campos obligatorios están marcados con *

Este sitio usa Akismet para reducir el spam. Aprende cómo se procesan los datos de tus comentarios.