An involuntary, rhythmic muscle contraction that causes shaking is known as a tremor. This movement disorder is a symptom arising from a problem in the parts of the brain that control movement. While tremors can occur at any age, they are particularly common among older adults. They can range from barely noticeable to movements that significantly interfere with daily living activities. Any new or worsening tremor warrants a medical evaluation to determine the underlying cause.
Defining the Types of Hand Tremors
Clinicians classify tremors based on when the shaking occurs. The two primary categories are resting tremors and action tremors. A resting tremor happens when the affected body part is fully relaxed and supported against gravity, such as when the hands are resting in the lap. This type of tremor typically lessens or disappears entirely during voluntary movement.
Action tremors, conversely, occur when the muscle is engaged in a voluntary contraction. This category is further subdivided into several types based on the activity. A postural tremor is present when holding a position against gravity, like keeping the arms outstretched. A kinetic tremor occurs during any purposeful movement, such as writing or bringing a cup to the mouth.
Primary Neurological Conditions
The most frequent cause of hand shaking in older people stems from two distinct neurological conditions: Essential Tremor (ET) and Parkinson’s Disease (PD). ET is significantly more common, characterized primarily by an action tremor. The shaking is most apparent when the person is actively using their hands, such as eating or writing, and often affects both sides of the body symmetrically.
The tremor associated with ET commonly involves the head, causing a “yes-yes” or “no-no” motion, and can also affect the voice. Although the exact cause remains unknown, ET is often hereditary, with a genetic component suspected in roughly half of all cases.
PD, by contrast, is classically associated with a resting tremor, manifesting when the hand is completely at rest. The tremor often begins on one side of the body and may present as a characteristic “pill-rolling” motion between the thumb and forefinger. PD is a progressive neurodegenerative disorder.
The key differentiating symptoms in PD include bradykinesia (slowness of movement), rigidity (stiffness), and postural instability (balance problems). These additional motor features, along with the unilateral onset of the tremor, help distinguish PD from Essential Tremor. The underlying pathology involves the loss of dopamine-producing cells in a specific area of the brain.
Non-Neurological and Reversible Factors
Tremors are not always caused by a neurological disorder; many factors can induce or enhance a benign tremor. Medication-induced tremor is a common occurrence, as many drugs can interfere with the nervous system’s control over muscle movement. Common culprits include certain anti-seizure medications, asthma drugs, and some psychiatric medications.
Systemic medical conditions can also trigger or worsen hand shaking by affecting the body’s metabolism. An overactive thyroid gland (hyperthyroidism) can lead to a fine, rapid tremor. Similarly, low blood sugar (hypoglycemia) can cause temporary shakiness that resolves once blood glucose levels are corrected.
Lifestyle factors and psychological states are also significant contributors to enhanced physiologic tremor, which is the high-frequency, low-amplitude shaking present in all people. Stress, anxiety, fatigue, and the consumption of too much caffeine can all amplify this natural tremor, making it noticeable and disruptive.
Medical Evaluation and Treatment
A medical evaluation begins with a detailed history and a physical examination to characterize the tremor. The neurologist will observe the tremor’s frequency and amplitude, and determine whether it is a resting or action tremor. Specific tasks, such as drawing a spiral or holding a position, are used to observe the tremor’s manifestation.
To rule out non-neurological causes, blood tests are often performed to check for hormonal imbalances, such as thyroid dysfunction, or other metabolic issues. In cases of diagnostic uncertainty, specialized imaging or neurological tests may be used to help differentiate between conditions.
Treatment strategies are highly dependent on the underlying cause, with the goal of improving the patient’s quality of life. For Essential Tremor, first-line treatments often include beta-blockers, such as propranolol, or anti-seizure medications like primidone. In contrast, Parkinson’s Disease tremors are typically managed with medications that increase or mimic the effects of dopamine.
When a tremor is medication-induced, the physician may adjust the dosage or switch to an alternative drug. For severe, medication-refractory tremors, surgical options like Deep Brain Stimulation (DBS) or focused ultrasound may be considered. Occupational therapy can also provide adaptive strategies and tools, such as weighted utensils, to help manage the impact of hand shaking on daily activities.