action tremor


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tremor

 [trem´or, tre´mor]
an involuntary trembling of the body or limbs; it may have either a physical or a psychological cause. Early symptoms include trembling of the hands and nodding of the head. Tremors are often associated with parkinson's disease, which affects nerve centers in the brain that control the muscles. They also occur in cerebral palsy, hyperthyroidism, and withdrawal from narcotics or alcohol. They tend to develop as one of the results of aging, and are sometimes symptoms of temporary abnormal conditions such as insulin shock, or of poisoning, especially metallic poisoning. They sometimes appear with a high fever resulting from an infection. Tremors of psychological origin take many forms, some minor and some serious. Violent, uncontrollable trembling is often seen in certain phases of severe mental disorders. If there is no physiological cause, they may be a sign of general tension.
action tremor rhythmic, oscillatory movements of the outstretched upper limb when voluntary movements are attempted, as when writing or lifting a cup; it may also affect the voice and other parts. Called also intention tremor and volitional tremor.
coarse tremor that involving large groups of muscle fibers contracting slowly.
essential tremor a hereditary tremor with onset at varying ages, usually at about 50 years of age, beginning with a fine rapid tremor (as distinct from that of parkinsonism) of the hands, followed by tremor of the head, tongue, limbs, and trunk; it is aggravated by emotional factors, is accentuated by volitional movement, and in some cases is temporarily improved by alcohol.
fine tremor one in which the vibrations are rapid.
flapping tremor asterixis.
intention tremor action tremor.
parkinsonian tremor a type of resting tremor commonly seen with parkinsonism, consisting of slow, regular movements of the hands and sometimes the legs, neck, face, or jaw; it typically stops upon voluntary movement of the part and is intensified by stimuli such as cold, fatigue, and strong emotions.
physiologic tremor a rapid transient tremor of extremely low amplitude found in the limbs and sometimes the neck or face of normal individuals, only subtly detectable on an electromyogram and seldom visible to the naked eye; it may become accentuated and visible under certain conditions.
rest tremor (resting tremor) one occurring in a relaxed and supported limb, such as a parkinsonian tremor.
senile tremor one due to the infirmities of old age.
volitional tremor action tremor.

in·ten·tion trem·or

a tremor that occurs during the performance of precise voluntary movements, caused by disorders of the cerebellum or its connections.

action tremor

A tremor that occurs during any type of movement of an affected body part. 

Types
• Postural tremor—Occurs when maintaining a position against gravity—e.g., holding arms outstretched. 
• Kinetic tremor—Appears during movement of a body part, such as moving the wrists up and down.
• Intention tremor—Present during a purposeful movement toward a target, such as touching a finger to one’s nose during a medical exam. 
Task-specific tremor—Appears when performing highly skilled, goal-oriented tasks, such as handwriting or speaking. 
Isometric tremor—Occurs during a voluntary muscle contraction that is not accompanied by any movement.

in·ten·tion trem·or

(in-ten'shŭn trem'ŏr)
A tremor that occurs during the performance of precise voluntary movements, caused by disorders of the cerebellum or its connections.
Synonym(s): volitional tremor (2) .

in·ten·tion trem·or

(in-ten'shŭn trem'ŏr)
Tremor that occurs during performance of precise voluntary movements, caused by disorders of cerebellum or connections.
Synonym(s): action tremor.
References in periodicals archive ?
With a view to better defining the clinical phenomenological classification of PD, our group relabeled the different PD tremor types in what appeared to us to be a more intuitive and logical way, as follows: type I, pure resting tremor; type II, mixed action and resting tremor with similar frequencies (subdivided into re-emergent and continuous tremors); type III, pure action tremor; and type IV, mixed action and resting tremor with different frequencies.
Resting and action tremor were considered to have similar frequencies when the difference in frequency peaks was below 1.5 Hz.
Type II is mixed resting and action tremor with similar frequencies, divided, according to action tremor presentation, into type II-R (re-emergent) when there is a time lag (usually 5-20 seconds) and type II-C (continuous) when there is no time lag.
In our series, we found the most common tremor presentation in PD to be mixed resting and action tremor (51% of the patients).
Our study found that action tremor is prevalent in PD.
Interestingly, we found that 19% of our patients had pure action tremor, that is, essential tremor-like tremor.
The basis for action tremor in PD is not clear [5].
Furthermore, as a weighted limb test was not performed, some degree of misdiagnosis cannot be ruled out in cases of physiological action tremor. The classification of pure action tremor is difficult because rest tremor may be very mild and intermittent, especially when patients are treated with dopaminergic drugs.
In humans and rats, lead exposure may lead to acute and chronic progressive disorders in which action tremor is a prominent feature (Booze et al.
Postural and action tremors (tremors that occur during movement) are caused by multiple health problems.