DEEP BRAIN STIMULATION
(DBS) IN PARKINSON’S DISEASE
Major Symptoms of Parkinson’s disease
Parkinson’s
disease (PD) is a progressive neurological disease, characterised by tremors,
rigidity, slowness of movements and postural imbalance. Though it is more common
after the age of 40, people younger than 40 can also get affected (when it is
known as young onset PD).
Other symptoms of
PD include low volume speech (sometimes totally incomprehensible),
expressionless face, reduced blink rate, reduced arm swing while walking,
stooped posture, small handwriting (called micrographia), short-shuffling steps,
tendency to fall forwards. Many people also have pain and aches in the affected
limbs. Sleep disturbance and restless leg syndrome are common comorbid
illnesses in people with PD. Severe memory impairment is NOT a feature of PD,
however, in advance PD, mild memory impairment may occur in about 10% of
patients. Similarly, loss of bladder control or erectile dysfunction is not a
feature of PD. When these features are present, one should suspect multiple
system atrophy (MSA).
Diagnosis of PD
The diagnosis of
PD is still best made on the basis of clinical examination by an experienced
neurologist (preferably trained in movement disorders, though not a must). PET
and DaT scans are available to help in the diagnosis of PD, but they are not
superior to a good clinical examination by an experienced neurologist.
Treatment of PD
Treatment of PD is
still primarily medical and DBS is not the first option.
The most effective
medicine is levodopa-carbidopa combination. If a patient does not respond to
levodopa treatment, we should doubt the diagnosis (it may not be PD). Even
though levodopa is the most effective medication, we should delay starting it
by 2-3 years, to avoid side effects and lack of efficacy later on. Other
medications in use are pramipexole, ropinirole, trihexiphenydyl, selegiline,
rasagiline, amantadine, entacapone, safinamide, etc.
Role of Deep Brain Stimulation (DBS) surgery in PD
DBS was approved
for PD in 2002. In the past 15 years, about 1,35,000 patients worldwide have
undergone DBS for PD.
What does DBS
surgery involve?
A neurosurgeon
places the leads (thin wires) that carry electrical signals to specific areas
of the brain. Then, the surgeon places a battery-run neurostimulator (like a
pacemaker) under the skin of the chest.
The surgeon may
use a programming device to adjust the settings. You may have a device, similar to a remote control, which allows you to
turn the system on and off and check the battery. You may also be able to
adjust the stimulation within options programmed by your doctor.
A neurologist initially evaluates a patient to determine whether he or
she is the right candidate for DBS surgery. Then, further evaluations include
brain imaging (MRI, CT, PET, etc), neuropsychological testing, UPDRS scoring,
etc. Once the patient is found to be suitable for DBS, he is referred to the
neurosurgeon.
Which patients are likely to benefit from DBS surgery?
1.
The diagnosis
of PD should be definite.
2.
Patient has had
PD for five years or more.
3.
Patient
continues to respond to levodopa, even though the response may or may not be
good.
4.
There are motor
fluctuations, such as on-off phenomena, with or without dyskinesia.
5.
Various medical
treatments have not had desired benefit.
6.
PD symptoms are
severe enough to interfere with activities of daily living.
Which patients are NOT likely to
benefit from DBS surgery?
1.
Patients with
atypical Parkinsonian symptoms,
2.
Patients with
multiple system atrophy (where bladder and sexual dysfunction are prominent
symptoms),
3.
Patients with progressive
supranuclear palsy,
4.
Patients with
dementia or severe cognitive impairment,
5.
Patients with
unstable psychiatric illnesses,
6.
Patients with
advanced PD, who are confined to bed/wheelchair; despite being on medications,
7.
Patients with
NO response to levodopa therapy,
Who are the best candidates for DBS surgery in PD?
1.
Excellent
response to levodopa therapy,
2.
Younger age,
3.
Mild or no
cognitive impairment,
4.
Few or no axial
(affecting neck or trunk) motor symptoms,
5.
Absence of or
well controlled psychiatric disease.
Are there any complications of DBS surgery?
DBS surgery is generally safe if performed by a trained group of
specialists. However, complications may occur in upto 3% of patients, which
include:
1.
Bleeding
(hemorrhage) in the brain,
2.
Infection,
3.
Stroke,
4.
Speech
impairment
5.
Erosion,
migration or fracture of the lead,
6.
Death
What to expect after DBS surgery?
Most patients report a reduction in severity of symptoms after surgery.
Tremors, dyskinesia, slowness all respond to the surgery.
PD medications, however, can not be stopped even after DBS. Most
patients still need to take medications, however, at much lower doses.
The benefits are seen at five years after surgery, however, the effect
tends to wane in later years.
DBS does not alter the disease progerssion, and disease continues to get
worse even after DBS.
Is MRI safe after DBS?
Yes, MRI can be safely done after DBS surgery.
What is the cost of DBS surgery ?
The cost of surgery is approximately INR 9,00,000 to 10,00,000.
Dr Sudhir Kumar MD
(Med) DM (Neuro)
Senior Consultant
Neurologist
Apollo hospitals,
Hyderabad
http://www.facebook.com/bestneurologist/
04023607777/60601066
