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[<A HREF="dbspdtremorglossary.html">Glossary of Terms</A>] |

[<A HREF="dbspdtremorabbrev.html">Abbreviations</A>]

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<p>

The recordings of this database are of rest tremor velocity in the index

finger of 16 subjects with Parkinson's disease (PD) who receive chronic

high frequency electrical deep brain stimulation (DBS) either uni- or

bi-laterally within one of three targets:</p>

<ul>

<li> Vim = the ventro-intermediate

nucleus of the thalamus (n=3), </li>

<li> GPi = the internal Globus pallidus (n=7), or</li>

<li> STN = the subthalamic nucleus (n=6).</li>

</ul>

<P>

This surgical procedure involves implanting an electrode into

subcortical structures (Vim, GPi or STN) for long-term stimulation at

frequencies greater than 100 Hz.  The mechanism by which high frequency

DBS suppresses tremor and reduces other symptoms in PD is unknown.</p>

<P>

Parkinson’s disease is characterized by the progressive loss of dopamine

neurons in the substantia nigra of the midbrain, and is associated with

motor symptoms including tremor (usually rest tremor, though sometimes

postural tremor), bradykinesia and rigidity.  In

Parkinson’s disease, tremor becomes more regular or harmonic, its

frequency is shifted to a lower range (typically 4–6 Hz), its amplitude

increases, the shape of its oscillations changes, and it fluctuates over

time.  These changes are subtle and intermittent at first, becoming more

permanent and obvious as the disease progresses.</p>

<div class="outer2"><div class="inner2">

<img src="g2.gif" alt="Parkinsonian rest tremor velocity recording (subject g2) under four conditions" style="width: 514px;">

<p style="width: 514px; margin: 1em auto; text-align: left;">

<em>Figure 1. Two seconds of Parkinsonian rest tremor velocity

(metres/second) recordings from subject g2 (stimulator implanted in the

GPi) under four conditions: (a) no stimulation and no medication, (b)

deep brain stimulation and no medication, (c) no stimulation and 150%

medication, (d) deep brain stimulation and 150% medication.  <B>Note the

zoomed vertical scale in (b), (c) and (d).</B></em></p>

</div></div>

<P>

Chronic high frequency deep brain stimulation of the Vim can decrease

tremor amplitude in a spectacular way.  Deep brain

stimulation of the GPi and STN have been shown to relieve not only

tremor but also other symptoms of PD such as rigidity and dyskinesia.

See Figure 1 for an example of the effect of deep brain stimulation of

the GPi on tremor.</p>

<P>

<div class="outer2"><div class="inner2">

<img src="vlaser.gif" alt="Velocity laser recording of rest tremor" style="width: 426px;">

<p style="width: 426px; margin: 1em auto; text-align: left;">

<em>Figure 2. Velocity laser recording of rest tremor.</em>

</p>

</div></div>

<P>

The raw data were obtained using a

low intensity velocity-transducing laser that was directed at a piece of

reflective paper on the subject’s index finger tip (Figure 2), with the output

voltage proportional to the velocity of the finger.</p>

<h2>DBS/Medication Conditions:</h2>

<p>Tremor was recorded for approximately 60 seconds under various

conditions:</p>

<ol>

<li> two conditions of DBS (on-off) and two conditions of medication

    (L-dopa on-off)<br>

    [total: 55 recordings of approx 60 seconds each]

<li> every 15 minutes when DBS was stopped for 60 minutes (medication off)<br>

    [total: 46 recordings of approx 60 seconds each]

</ol>

<p>Please note that not all subjects were tested under all conditions.</p>

<P>

For the "medication off" condition, the subject did not take

any medication for at least 12 hours.  For the "medication on"

condition, the subject took 150% of his or her morning dose of

dispersible Modopar and testing began after the neurologist determined

the medication had taken effect (approximately 40 minutes).</p>

<h2>Subjects:</h2>

<p>The 16 subjects can be divided into two groups: </p>

<ol>

<li> Subjects 1&ndash;8 with high amplitude tremor (HAT) who are receiving DBS

to relieve tremor (Group 1), and </li>

<li> Subjects 9&ndash;16 with low amplitude tremor (LAT) who are receiving DBS to

relieve other symptoms such as rigidity or dyskinesias (Group 2).</li>

</ol>

<p>The file <A HREF="subject_description.txt">subject_description.txt</A>

contains information on the 16 subjects:</p>

<div class="edbtable">

<table>

<tr><th>Information</th><th>Description</th></tr>

<tr><td>SUBJECT</td><td>2 character subject identification: <br>

Stimulation target (v=Vim, s=STN, g=GPi), and<br>

Subject number (1-16)</td></tr>

<tr><td>AGE</td><td>Age at the time of testing (years)</td></tr>

<tr><td>GENDER</td><td>Male (n=11) or female (n=5) </td></tr>

<tr><td>STIM TARGET</td><td>Vim = ventro-intermediate nucleus

of the thalamus<br>GPi = internal Globus Pallidus<br>STN=subthalamic

nucleus </td></tr>

<tr><td>BI/UNI-LATERAL</td><td>Bilateral stimulation (n=12) or

unilateral stimulation (n=4)</td></tr>

<tr><td>EFF FREQ</td><td>Frequency (Hz) of effective

stimulation (> 100 Hz) </td></tr>

<tr><td>INEFF FREQ</td><td>Frequency (Hz) of so-called ineffective

stimulation (< 100 Hz) </td></tr>

<tr><td>INTENSITY</td><td>Stimulation intensity (V)</td></tr>

<tr><td>PULSE WIDTH</td><td>Stimulation pulse width (&micro;sec)</td></tr>

<tr><td>MODE</td><td>Cont = continuous

stimulation,<br>Cycl=cyclic stimulation (e.g. 1 minute on, 1 second

off)</td></tr> 

<tr><td>STIM CONTACTS</td><td>Listed in order of proximal

distal direction on quadripolar stimulating electrode:<br>

- negative polarity<br>+ positive polarity<br>. not stimulated

</td></tr> 

<tr><td>YEAR DIAGNOSED</td><td>Year diagnosed with

Parkinson's disease</td></tr> 

<tr><td>YEAR DBS RIGHT</td><td>Year of right brain DBS surgery</td></tr> 

<tr><td>YEAR DBS LEFT</td><td>Year of left brain DBS surgery</td></tr> 

<tr><td>TOT DAILY MED</td><td>Total medication of morning,

noon and evening doses (mg)</td></tr> 

<tr><td>150% SINGLE DOSE</td><td>Dose taken before testing

&quot;medication on&quot; condition (mg)</td></tr> 

</table>

</div>

<h2>Filename Structure:</h2>

<p>The file name structure of the records is:</p>

<ul>

<li> 2 character subject identification: stimulation target (v=Vim,

s=STN, g=GPi) and subject number (1&ndash;16)</li>

<li> 1 character tremor type: r = resting tremor</li>

<li> 1 character DBS condition: e = effective (> 100 Hz), o = no

stimulation</li>

<li> (optional) 2 character time since stimulator arrest: if a 2 digit

number follows the DBS condition, it indicates the number of minutes

since the stimulation was stopped</li>

<li> 1 character medication condition: n= medication on, f=medication

off</li>

<li> 3 character extension indicates the side tested: let = left index

finger tremor, rit = right index finger tremor</li>

</ul>

<h3>Filename Examples:</h3>

<ul>

<li><kbd>s6ren.let</kbd> contains a recording

(approx. 60 sec) of rest tremor in the left index finger of subject 6 in

the "dbs on and medication on" condition: the subject had

taken 150 % of his or her morning dose of L-dopa and was receiving

&quot;effective&quot; stimulation of the STN.</li>

<li> <kbd>v4rof.rit</kbd> contains a recording

(approx. 60 sec) of rest tremor in the right index finger of subject 4

in the "dbs off and medication off" condition: the subject was

off medication for at least 12 hours and the subject's stimulator

(implanted in the Vim) was switched off.</li>

<li> <kbd>g1r30of.rit</kbd> contains a recording

(approx. 60 sec) of rest tremor in the right index finger of subject 1 at

30-minutes after the stimulator (implanted in the GPi) was switched off.

Also, this subject was off medication for at least 12 hours.</li>

</ul>

<h2>Tremor Recordings:</h2>

<p>The rest tremor recordings can be classified as one of 8 categories, for

subjects with high amplitude tremor (HAT) and for subjects with low

amplitude tremor (LAT):</p>

<ol>

<li> <strong>ren:</strong> Deep brain stimulation on, Medication on<br>

     HAT subjects: n=5 recordings<br>

     LAT subjects: n=8 recordings</li>

<li> <strong>ref:</strong> Deep brain stimulation on, Medication off<br>

     HAT subjects: n=5 recordings<br>

     LAT subjects: n=8 recordings</li>

<li> <strong>ron:</strong> Deep brain stimulation off, Medication on<br>

     HAT subjects: n=7 recordings<br>

     LAT subjects: n=8 recordings</li>

<li> <strong>rof:</strong> Deep brain stimulation off, Medication off<br>

     HAT subjects: n=6 recordings<br>

     LAT subjects: n=8 recordings</li>

<li> <strong>r15of:</strong> Deep brain stimulation off for 15 minutes,

     Medication off<br> 

     HAT subjects: n=3 recordings<br>

     LAT subjects: n=8 recordings</li>

<li> <strong>r30of:</strong> Deep brain stimulation off for 30 minutes,

     Medication off<br> 

     HAT subjects: n=4 recordings<br>

     LAT subjects: n=8 recordings</li>

<li> <strong>r45of:</strong> Deep brain stimulation off for 45 minutes,

     Medication off<br> 

     HAT subjects: n=3 recordings<br>

     LAT subjects: n=8 recordings</li>

<li> <strong>r60of:</strong> Deep brain stimulation off for 60 minutes,

     Medication off<br> 

     HAT subjects: n=4 recordings<br>

     LAT subjects: n=8 recordings</li>

</ol>

<table>

<tr><td>Total:</td><td>HAT subjects: n=37 recordings<br>

                       LAT subjects: n=64 recordings</td></tr>

</table>

<p>

The file <A HREF="file_description.txt">file_description.txt</A>

contains a summary of recordings per subject in each category.  </p>

<h2>Reference:</h2>

<div class="reference">

<p>

Beuter, A., Titcombe, M.S., Richer, F., Gross, C., Guehl, D., 2001.

Effect of deep brain stimulation on amplitude and frequency

characteristics of rest tremor in Parkinson's disease.  

<em>Thalamus &amp; Related Systems</em>, Volume 1 (3): 203&ndash;211

(published by Elsevier Science).</p>

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