COORDINATION EXAM: ABNORMAL EXAMPLES
Speech Rapid Alternating Movements Dysarthria
Impaired speech articulation of cerebellar origin is characterized by being slow, indistinct, and scanning (scanning refers to decomposition of words into monosyllabic parts and loss of normal phrasing and intonation).
A cerebellar intention tremor (1st scene in this movie) arises mainly from limb girdle muscles and is maximal at the most demanding phase of the active movement. This must be distinguished from a postural tremor (fine distal 8-13 Hz)(2nd scene) or resting tremor (coarse distal 5-6 Hz pill-rolling type of tremor)(3rd scene).
Increased range of movement with lack of normal recoil to original position is seen in cerebellar disease.
The patient is unable to stop flexion of the arm on sudden release so the arm may strike the chest and doesn't recoil to the initial position. This is most likely due to failure of timely triceps contraction.
Hand Rapid Alternating Movements
Movements are slow and irregular with imprecise timing. Inability to perform repetitive movements in a rapid rhythmic fashion is called dysdiadochokinesia.
Under (hypometria) and over (hypermetria) shooting of a target (dysmetria) and the decomposition of movement (the breakdown of the movement into its parts with impaired timing and integration of muscle activity) are seen with appendicular ataxia.
Foot rapid alternating movements
Movements are slow and irregular with imprecise timing of agonist and antagonist muscle action.
Same as finger-to-nose except for the lower extremities. For both the upper and lower extremities, it is important to always compare right versus left.
The patient with ataxia of the lower extremity will have difficulty placing the heel on the knee with a side-to-side irregular over- and undershooting as the heel is advanced down the shin. Dysmetria on heel-to-shin can be seen in midline ataxia syndromes as well as cerebellar hemisphere disease so there is overlap between the two types of ataxias for this finding.
Patient's feet will be placed wider apart then usual in order to maintain balance (broad or wide-based station). Midline ataxias cause instability of station with eyes opened or closed.
Wide-based, unsteady, irregular steps with lateral veering; ataxia is most prominent when sudden changes are needed such as turning, standing up or stopping.