Neurology diagnoses and treats disorders of the nervous system, including the brain, spinal cord, and nerves, as well as thought and memory.
Send us all your questions or requests, and our expert team will assist you.
Tremor is the most common movement disorder encountered in neurological practice. It is defined as an involuntary, rhythmic, oscillatory movement of a body part. Unlike other hyperkinetic disorders like chorea (which is random and flowing) or myoclonus (which is sudden and shock like), tremor is characterized by a relatively stable frequency and amplitude. It is produced by alternating or synchronous contractions of agonist and antagonist muscles.
The neurological basis of tremor lies in the disruption of the brain’s central oscillators. Just as the heart has a pacemaker, the brain has neural circuits that can generate rhythmic activity. Under normal conditions, these physiological oscillations are dampened. However, in pathological states, specific loops, primarily involving the cerebellum, thalamus, and brainstem—become hyper-synchronized, driving the rhythmic tremor output to the periphery.
Neurologists classify tremor based on its “activation condition”—when it happens. Resting tremor occurs when the muscle is completely relaxed and supported against gravity. Action tremor occurs during voluntary movement. Action tremor is further subdivided into postural (holding a position), kinetic (moving), and intention (approaching a target) tremor. This phenomenological classification is the first step in localizing the neurological lesion.
The anatomy of tremor is complex, but the cerebello-thalamo-cortical pathway is the central highway implicated in most tremor syndromes. The cerebellum is the brain’s error correction center. It receives information about where the limb is and where it should be. If the cerebellum or its outflow tracts are damaged or dysregulated, the error correction signal becomes unstable, resulting in oscillation.
Signals travel from the cerebellum to the thalamus (specifically the Ventral Intermediate Nucleus, or Vim), and then to the motor cortex. In conditions like Essential Tremor, it is believed that neurodegeneration or GABAergic dysfunction in the cerebellum disinhibits this pacemaker, sending a rhythmic “noise” signal through the network that manifests as shaking in the hands.
Resting tremor, the hallmark of Parkinson’s disease, involves a different circuit: the basal ganglia. The loss of dopamine producing cells in the substantia nigra disrupts the balance of the direct and indirect pathways. This leads to the emergence of pathological beta band oscillations (13-30 Hz) in the subthalamic nucleus and globus pallidus.
This abnormal rhythm locks the motor cortex into a synchronized state, preventing the fluid initiation of movement and generating the characteristic “pill rolling” tremor at rest. Unlike cerebellar tremor, which is an error in motion, basal ganglia tremor is a release of inhibition during stillness. It often abates when the patient initiates a voluntary action, illustrating the distinct physiology of these two systems.
It is important to understand that everyone has tremor. Physiological tremor is a high frequency, low amplitude oscillation inherent to the mechanical properties of the limbs and the firing rates of motor neurons. It is usually invisible to the naked eye. It becomes “enhanced physiological tremor” when visible, often driven by adrenaline, caffeine, or fatigue stimulating the peripheral beta adrenergic receptors.
Pathological tremor arises from a structural or functional defect in the nervous system. The frequency of the tremor often gives a clue to its origin. Orthostatic tremor, a rare condition where the legs shake only when standing still, has a very high frequency (13-18 Hz). Palatal tremor involves rhythmic movements of the soft palate and has a slow frequency (1-3 Hz), often linked to brainstem lesions.
Send us all your questions or requests, and our expert team will assist you.
A tremor is a rhythmic, back and forth oscillation that occurs at a regular speed, whereas a spasm is a sudden, irregular, and often sustained muscle contraction that does not oscillate.
Strong emotions release adrenaline (epinephrine), which stimulates the beta receptors in your muscles, temporarily increasing your natural physiological tremor to a visible level.
No, the most common cause of tremor is actually Essential Tremor, which is a different neurological condition; tremor can also be caused by medication, thyroid issues, or anxiety.
An intention tremor is a specific type of shaking that gets worse as your hand gets closer to the object you are trying to touch, usually indicating a problem in the cerebellum.
Yes, if the tremor affects the muscles of the larynx (voice box) or diaphragm, it can cause a shaky or quivering voice, which is common in Essential Tremor.
essential tremor About 10 million people in the United States deal with uncontrollable shaking, often in their hands. This is called essential tremor. It makes
Leave your phone number and our medical team will call you back to discuss your healthcare needs and answer all your questions.
Your Comparison List (you must select at least 2 packages)
