Illustrative Through writing and drawing, you can easily identify various tremors

When people develop symptoms of tremor, having them do simple writing and drawing tasks can help confirm the diagnosis
.
These tasks, although taking some time to complete, provide a wealth of clinical information, and common causes of tremor have characteristic patterns
on these tests.
This article describes how to maximize the diagnostic value
of these handwritings.

Each type of tremor has a unique expression
in writing and painting.
There is no absolute right or wrong
in the specific operation of handwriting checking.
During the examination, it is best to ask the patient to perform 3 tasks in full: writing, drawing spirals, drawing straight lines
.

In the writing check, the writing example used in this article is "Mary had a little lamb.
"
Usually, it is sufficient for the patient to do it once, but in some cases, the symptoms will become more pronounced
after the patient has written repeatedly.
For example, people with Parkinson's disease have a gradual decrease in font size when writing, which may need to be expressed by task addition
.

In the patterned examination, the doctor first draws the Archimedean spiral and asks the patient to redraw the sample, first with the dominant hand and then with the non-dominant hand
.
There are also doctors who like to dangle the gesture as an example, and let the patient determine the size
of the drawing himself.

Finally, the patient is asked to draw a horizontal line and a vertical line with each hand, at least 10 cm
long.
If there are no significant abnormalities in the drawing results, the patient is asked to lift their hand off the paper during the task to amplify the patient's tremor manifestations
.

The following table lists the handwriting findings
of the various types of tremor.
Example illustrations will be used to illustrate the handwriting characteristics
of different tremors.

Even for experienced movement disorder specialists, early essential tremor and mild bilateral dystonic tremor are among
the most difficult types of tremor to distinguish.
This is where writing and drawing tasks come into
play.

Essential tremor is characterized by small amplitude (less than 1cm) and high frequency (8~12Hz), in order to make it easier to see whether the patient's amplitude and frequency are stable, the patient can be required to draw a straight line perpendicular to the tremor axis at a stable rate, and the frequency can be calculated
by timing.

A: Archimedes spiral shows a unidirectional tremor axis of 8 o'clock ~ 2 o'clock, suggesting the possibility of essential tremor, but it is not clear whether the amplitude and frequency of tremor are constant
.
However, the straight line drawn by the patient shows a regular tremor frequency, with the line amplitude drawn perpendicular to the tremor axis more pronounced, and it can be seen that the amplitude
is indeed constant.

B: Shaky notes in the patient's writing suggest essential tremor or dystonic tremor
.
The Archimedes spiral drawn by the patient shows that the right hand spiral is the 8~2 o'clock tremor axis, and the left hand spiral is the 10~4 o'clock tremor axis, which suggests essential tremor
.
However, due to the overlap of turns due to severe tremor, it is difficult to judge the amplitude and frequency
from the spiral.
Through the drawing of the straight line, it can be seen that the left hand (main) vertical line has 18 tremors in 2 seconds, with an estimated frequency of 9Hz
.

C: In this example, a plot drawn by a patient with severe essential tremor shows a clear large tremor in the unidirectional axis, with fairly regular amplitude and frequency, and bilateral symmetry
.
An increase in spiral spacing can sometimes be seen in severe essential tremor, which may reflect manifestations
of ataxia as part of the disease.

Fig.
1 Essential tremor

In contrast to essential tremor, dystonic tremor is often multidirectional.

The Archimedean spiral drawn by the patient can clearly show this feature
.
Because dystonic tremor can affect both the proximal shoulder, elbow, and distal hand muscles, the direction of the tremor is also different
.
It is important to note that axial analysis of the Archimedes spiral does not conclusively distinguish dystonic tremor
.

More clues
can be obtained by observing the magnitude of the tremor.
In dystonic tremor, the patient's tremor axis and amplitude fluctuate, and this fluctuation makes the patient's pattern look "dumb"
.
Tremors are usually asymmetrical and less frequent (< 7 Hz), and abnormal posture of the arm may occur, causing the patient to put so much pressure on the nib that the task cannot be completed<b12>.
Sometimes patients with dystonic tremor have much more difficulty writing than drawing, reflecting the task specificity
of dystonia.

A: Tremor occurs in all parts of the spiral, suggesting a multidirectional axis
.
The amplitude and frequency of tremor also varies, taking on a dull appearance
.

B: This patient is very forceful in the process of writing and drawing, consistent with the dystonic posture, and the spiral drawn by the left hand shows a multidirectional tremor axis
.
The researchers noticed that many dystonia patients tend to draw spirals
of more than 3 circles.
When the patient is asked to draw straight lines at a steady speed, the patient's tremor frequency is variable, especially vertical lines
.
On the horizontal line and spiral chart, the patient's tremor amplitude is asymmetrical, with a larger
right side.

C: The spirals and lines drawn by this patient also appear as variable tremor amplitude and frequency, resulting in a jerky
appearance.
However, in this case, the patient's writing was basically normal, with only a small tremor
.

Fig.
2 Dystonic tremor

People with Parkinson's disease usually write and draw slowly, and write small words with tight spiral turns
.
Small and slow writing is characterized by bradykinesia, which is the main motor feature
in patients with Parkinson's disease.
If the patient usually writes very little, drawing the spiral is more sensitive
for diagnosis.
In addition, a gradual decrease in the speed and size of writing occurs in some patients with Parkinson's disease, but not all patients have this manifestation
.

During the mapping process, nearly half of Parkinson's patients had action tremor
.
Parkinson's disease tremor has a similar axis to essential tremor, and a decrease in helix diameter and an increase in turns density are a differentiating point
.

A: The spiral drawn by a Parkinson's disease patient (right) is smaller and the turn is more compact
than the one drawn by the doctor.
There was no evidence of
action tremor in this case.

B: In this case, the patient presents with severe bilateral tremor, which was initially mistaken for essential tremor
.
When drawing the spiral, the patient draws the spiral with tight turns, a one-way tremor axis, and a very slow
process.
Tremor becomes more pronounced as the patient accelerates the drawing of the outer ring of the spiral, a common pattern
in Parkinson's disease.

C: In this case, the writing and spiral drawing of the right hand of the patient were basically within the normal range, and the spiral drawn by the left hand showed a slight tremor, and the overall size was slightly reduced
.
The lines drawn by the patient showed more amplitude and frequency variation than in the average Parkinson's disease patient, who had atypical Parkinson's disease motor tremor
.

Fig.
3 Parkinson's disease tremor

A key feature of functional tremor is inconsistency, so it is critical to compare tremor differences
between different writing and drawing in repeated examinations.
Although dystonic tremor is somewhat activity-dependent, functional tremor is more variable in comparison
.
The frequency of tremor can vary within a single spiral or after a change of hands, or it may be problematic when drawing a spiral clockwise, and counterclockwise has no effect
.
In addition, tremors that are often more severe
when drawing lines are usually worse than writing and drawing spirals.

A: In this case, the patient had tremor in both hands, but on the spiral drawn by both hands, the amplitude and frequency changed
.

B: When the patient draws the spiral in a clockwise and counterclockwise direction, there is a clear difference
in the resulting pattern.

C: In this case, the patient has been manifested as a one-way (8~2 o'clock direction) tremor
of the right hand (dominant side).
However, when the spiral is drawn repeatedly, the characteristics of the spiral are inconsistent, suggesting dysfunction
.
In addition, the patient's drawing spiral is completed quickly, but the drawing line keeps stuck, and it can be seen that the amplitude and density of the straight line drawn by the patient increase, especially on
the vertical line.

Figure 4 Functional tremor

Writing, drawing spirals, and drawing straight lines are a convenient and quick way to provide objective evidence of abnormal neurological symptoms and help identify
tremors.
Look for these features when differentiating tremor:

➤ Essential tremor - higher frequency, smaller amplitude, uniaxial, symmetrical;

➤ dystonic tremor - low frequency, variable or violent amplitude, asymmetric, multidirectional axis, large pen pressure;

➤Parkinson's disease tremor - words are getting smaller and smaller, spiral curves are tightly spaced, uniaxial, asymmetrical, slow completion;

➤ Functional tremor – Variable characteristics when completing tasks repeatedly or with both hands
.

Compiled by: Alty J, Cosgrove J, Thorpe D, et al.
How to use pen and paper tasks to aid tremor diagnosis in the clinic[J].
Practical Neurology, 2017:practneurol-2017-001719.