Become a master at effectively inducing and recognizing extrapyramidal symptoms (EPS) when performing a clinical examination for extrapyramidal motor dysfunction. In this video, you'll learn the clinical signs of extrapyramidal disorders and how to conduct the neurological examination accordingly.
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[00:00:00] Basal ganglia disorders are associated with either too much or too little movement. Hypokinetic movement disorders refer to too little movement. As seen in Parkinson's disease and Parkinsonism. Hyperkinetic movement disorders are characterized by an excess of movement. The classic hypokinetic movement disorder is Parkinson's disease. It occurs as the result of a loss of dopamine-producing neurons
[00:00:30] in the substantia nigra of the midbrain. Recall that the indirect pathway generally results in decreased motor activity with the loss of nigra dopamine, there is an excess of activity of the indirect pathway within the basal ganglia, resulting in the excess globus pallidus interna activity suppressing the thalamocortical tracts, which normally promote activation of the motor neurons and thus the
[00:01:00] corticospinal tract. Parkinson's disease is classically associated with a series of movement issues. Rigidity is present and has a characteristic called cogwheeling due to ratchet-like action, the tremor tendency in parts. The resting tremor has a pin-rolling characteristic although many Parkinson's patients also have a postural tremor. Bradykinesia is a slowness or poverty of movement often best seen in the face. There is a decreased blink rate
[00:01:30] and the lack of vocal projection as well. Postural instability refers to the gait festination and tendency to fall backward or retropulsed. Often the tremor and cogwheeling appear unilaterally early during the disease. Parkinsonism refers to the appearance of features of Parkinson's disease in a patient, which may be due to other pathology of the nervous system. Etiologies of Parkinsonism include Parkinsonian syndromes
[00:02:00] such as the multiple system atrophy, drug-induced or iatrogenic causes like exposure to Reglan or antipsychotics, strokes in the striatal nigra tracts or the substantia nigra or other dementias like normal pressure hydrocephalus. When examining for Parkinson's disease, one should observe the patient's movements particularly the gait and the face. In addition to the classic Parkinsonian gate known as festination,
[00:02:30] one will also see bradykinesia including a decreased blink rate. Observe for the presence of the typical tremor, which has a four to eight hertz pin-rolling characteristic present at rest. If you ask the patient to do something with the affected hand, you can see the tremor suppress. cogwheel rigidity is elicited by moving a limb at two joints. One can rotate the wrist inflection and extension while flexing and extending the elbow for instance.
[00:03:00] Sometimes having the patient tap with the opposite hand while doing this maneuver can make the cogwheeling more pronounced. Lastly, you should also test for retropulsive tendencies with the pull test. Hyperkinetic movement disorders are characterized by an excess of involuntary movement that we can classify by type. Chorea refers to brief, abrupt, involuntary jerking movements. Chorea is the classic symptom seen in patients with Huntington's disease. Ballism
[00:03:30] is a rare form of Chorea, characterized by involuntary jerking or flinging movements of the limbs often affecting proximal muscles. Tics are involuntary sudden rapid repetitive movements of any group of muscles often involving the face and may affect the voice with grunts or vocalizations. These are a common characteristic of Tourette Syndrome. Dystonias are involuntary sustained muscle contractures causing unnatural twisting or posturing.
[00:04:00] To best illustrate hyperkinetic movement disorders, we can look at the clinical disorder of Huntington's disease. Huntington's disease is a genetic disorder with an insidious onset characterized by involuntary chorea formic movements and cognitive changes with psychiatric manifestations. The pathology involves the loss of neurons in the caudate and putamen. This leads to a favoring of the direct pathway, which facilitates motor activity of the cortex.
[00:04:30] Loss of GABA inhibition in the globus pallidus results in increased cortical motor enhancement and chorea results. The loss of neurons in the caudate and putamen can be readily seen on CT scan or MRI.