The 4-5 Hz tremor is most apparent when the arm is fully relaxed (supported and at rest, in an armchair). It is increased by mental calculation and stress and best seen during walking. It is reduced by action and intention (tricks used by the patients to hide the tremor). The classical description is the "pill-rolling" rhythmic alternating opposition of the thumb and forefinger. Some patients have postural tremor in particular conditions (holding a phone) with a different frequency (6 Hz).
This is the most disabling feature in PD as it involves the whole range of motor activity with a decrease in amplitude and rhythm of movement. Automatic movements disappear. Bradykinesia is well explored in the motor items of UPDRS III, the Unified Parkinson Disease Rating Scale (finger tapping, alternating pronation/supination movements, foot tapping, etc.), with rapid decline in amplitude and frequency.
Abnormal tone is observed when the patient is relaxed and the limb passively flexed and extended. Passive circling movements are better to test rigidity, as the patient cannot voluntarily "help" the passive movement (whereas active movement is sometimes superimposed to the passive movement during simple flexion-extension movements).
The Froment sign is classically described as an increase in tone of the limb during contralateral active movements. The actual sign, described by Jules Froment, was an increase of tone in the examined limb as the patient bent to reach a glass of water on the table (both postural adaptation and voluntary movement of the contralateral limb).
The cogwheel phenomenon is not pathognomonic of PD or parkinsonism and reflects the underlying tremor (can be observed in severe and disabling postural tremor) (2,3).
This is observed when the patient moves spontaneously (rising from a chair, pivoting when turning, etc.). The patient will take extra steps in pivoting and may have a careful gait. Postural challenge consists of a thrust to the shoulders (the examiner stays behind the patient to prevent a fall and the patient is instructed to resist the thrust). According to the UPDRS III score, one can observe a retro-pulsion (more than one step backward), but the patient recovers unaided (score 1); absence of postural response, the patient would fall if not caught by the examiner (score 2); the patient is very unstable, tends to lose balance spontaneously (score 3); the patient is unable to stand without assistance (score 4). This pull test is not standardized and each neurologist has his or her own technique. As a consequence, the examiner may adapt (consciously or not) the intensity of the thrust to the expected reaction of the patient! (see video segment 1.)
Only scores 0 (normal) and 1 are observed in PD until a later stage. In contrast, early postural instability is observed in MSA (with walking difficulties) and particularly in PSP (cardinal sign). Spontaneous falls (without warning or obstacle, occasional then frequent) occur in PSP (4) with loss of anticipatory postural reflexes, reactive postural responses, or rescue and protective reactions (the patient does not use his arms to keep balance and does not throw out his arms to break the fall and protect the head from injuries).
At an early stage of parkinsonism, slowing and shuffling of gait with dragging of the affected limb is common. A flexed posture of the arms (unilateral then bilateral) with a loss of arm swing is observed.
In contrast, in "vascular" parkinsonism or normal-pressure hydrocephalus, the arm swing is preserved or even exaggerated (to keep the balance) and the arms are not flexed. In that case, "parkinsonism" predominates in the lower limbs (thus the name of "lower body parkinsonism"). The "marche a petits pas" described by Dejerine is suitable for the description of these patients. The gait is characterized by short quick steps, initially without dragging or shuffling the feet on the ground (in contrast to PD), with start and turn hesitation (take several steps on turning), slight wide base (but can be narrow), and moderate disequilibrium (described by Nutt and colleagues as "frontal gait disorder") (5). Visual clues (contrasted lines on the ground) do not help these patients (in contrast to PD). The diagnosis of vascular origin (differential diagnosis from degenerative parkinsonism) is made by the company it keeps: pyramidal signs, dysarthria and pseudo-bulbar signs, urinary disturbances, cognitive signs, and stepwise progression with past medical history of acute motor deficits. In time, patients may develop a magnetic gait (the feet are glued to the ground) and astasia-abasia (they do not know how to walk anymore). Overall, the gait is different from those of patients with late PD or even PSP or MSA.
Gait disorders in PSP have been described as "subcortical disequilibrium." This gait pattern is characterized by a severe postural instability, loss of postural reflexes (cf. supra), and inappropriate response to disequilibrium (e.g., when rising from a chair, the patient will extend the trunk and neck and fall backward). The gait is also impaired by the disequilibrium, and is characterized by a wide base. Some patients do not hesitate to walk briskly, and are careless of the risk of falls (as if they did not realize they were in danger of falling).
Freezing and gait ignition failure are defined by a marked difficulty with initiating gait and difficulties maintaining locomotion in front of various obstacles (door, modification of the pattern of the floor, turning). They are observed at a late stage in PD or at earlier stages in MSA patients. They may be associated with various gait disturbances. Pure gait ignition failure is a different disorder, still poorly defined and, to date, with few clinical-pathological correlations (mostly associated with PSP).
In summary, a parkinsonian syndrome is easily explored, and may take only a few minutes. Spontaneous movements (or the lack of them) are observed when the patient and spouse are providing the medical history. Clumsiness and slowness are detected when patients are searching for documents or glasses in their bag, and when they take off or put on their jacket and shirt (buttons). Writing a few sentences will demonstrate the micrographia; walking in the examination room or corridor will help to detect a resting tremor, loss of arm swing, flexed posture, general slowness, and difficulties of gait and turning. The pull test will explore postural instability. In the end, the UPDRS III motor score will give a quantification of the severity of the parkinsonian syndrome.
Was this article helpful?
Are you sick of feeling like the whole world Is spinning out of control. Do You Feel Weak Helpless Nauseous? Are You Scared to Move More Than a Few Inches From The Safety of Your Bed! Then you really need to read this page. You see, I know exactly what you are going through right now, believe me, I understand because I have been there & experienced vertigo at it's worst!