Left Hypoglossal Nerve Palsy

Tongue deviation to left side on protrusion, is suggestive of left hypoglossal nerve palsy
At rest within the oral cavity, mild wasting of tongue muscles on the left can be noted.

Here you can see two images from a patient suffering from left hypoglossal (12th cranial) nerve palsy. In the first image, the tongue deviates to the left side (the side on which 12th cranial nerve is affected) on protrusion. In the second image, when the tongue is kept within the oral cavity, mild wasting on the left side of tongue is noted.

Deviation to the affected side is also noted in trigeminal nerve (5th cranial nerve) motor palsy. On the other hand, in cases of facial (7th cranial) and vagus (10th cranial) nerves, the deviation occurs to the normal (unaffected side).

In case of 12th cranial nerve palsy, one should look for long tract signs such as pyramidal tract signs, which could indicate an intrinsic brain stem lesion. In pure cranial nerve palsy, the causes are extra-axial. Common causes include diabetic cranial neuropathy, infections, tumors, etc.

Wasting of First Dorsal Interossei (small muscles of hand)

In the picture above, you can see a depression in the first web space (between thumb and index finger). This is suggestive of wasting of first dorsal interosseous (FDI) muscles. This patient had bilateral C8-T1 lesion.

Small muscle wasting can have varied localizations: Lower cervical cord lesion, anterior horn cell disease, C8-T1 root lesion, lower trunk plexopathy and ulnar nerve lesion. Careful clinical examination is required, before investigations such as MRI cervical spine, nerve conduction studies and EMG can be ordered for.

Split hand sign: It is specific for amyotrophic lateral sclerosis (ALS). In ALS, there is wasting of FDI muscles, associated with thenar muscle wasting. However, hypothenar muscles are relatively spared. See the picture below (source: Med J DY Patil Univ)

Essential Tremors

Essential tremors are the commonest causes of tremors in the world. These are also known as familial tremors or benign tremors. Tremors are often bilateral and commonly involve hands. In some cases, asymmetry may be seen, as in the case shown here, where the tremors are present only in left hand. Tremors can also involve head or voice. Tremors are absent at rest (unlike Parkinson’s disease, where tremors are seen at rest), and are brought on by action such as holding an object, writing or drinking a cup of coffee.

There is no diagnostic test and the diagnosis is made based on the clinical characteristics. Treatment is with medications such as propranolol, topiramate, mysoline or clonazepam. In severe cases, deep brain stimulation surgery may be offered.


Blepharospasm refers to involuntary contraction of eyelids. Eyelid closure are intermittent and of short duration. Spasms of eyelids may get triggered by light, wind, pollution, stress, etc. Here, you can also facial grimacing. These symptoms can occur as a part of Meige syndrome, which is more common in women, and commonly affects people between the ages of 40 and 70 years.

There is no specific test for diagnosis, and it is made on the basis of clinical characteristics.

The treatment of choice is botox (botulinum injections), which need to be repeated every 3-6 months. Some patients may respond to medications such as trihexiphenidyl, clonazepam or baclofen.

Using Hand Sanitizer May be Giving You a False Sense of Security

After a cough or sneeze, we quickly rub some ethanol-based sanitizer on our hands, assuming that all the germs and microbes have died. However, a recent study conducted in Japan showed contradictory results. It took as long as 4 MINUTES for the flu viruses to be killed. This is because their hands were still wet with mucus and flu viruses can survive longer on hands wet with mucus.

So, if you are using hand sanitizer to protect yourself and others from flu viruses, you need to wait for as long as 4 minutes to be fully safe that germs have died, or first dry your hands from mucus and then apply hand sanitizer, in which case, it would take lesser time (two minutes or lesser).

Or best is follow the Center for Disease Control and Prevention (CDC), USA guidelines, when you sneeze next:

1. Wet your hands with clean running water and apply soap to a lather
2. Scrub all surfaces: palms, backs, fingers, between fingers, under nails
3. Scrub for 20 seconds (that’s the time it takes to sing ‘Happy Birthday” twice)
4. Rinse under clean, running water, dry hands with clean towel or air dry.

Dr Sudhir Kumar MD DM

Gait in Parkinson’s Disease

Parkinson’s disease (PD) is the commonest movement disorder. Patients with PD have typical features, including gait, which can aid in prompt diagnosis. In this video, you can see a person with right hemi-parkinsonism. She has resting tremors, and the upper limb is kept flexed at elbow. There is stooped posture and reduced arm swing on the right side. Face looks expressionless and the blink rate is reduced. Steps are relatively shorter.

Tremors in Parkinson’s Disease

Tremors are among the commonest symptoms of Parkinson’s disease. In the above video, you can see tremors affecting the right hand in a middle aged woman suffering from Parkinson’s disease. These are also called as “drum-beating” tremors. The frequency of these tremors is 4-5 Hz. There are no tremors in the left hand. These tremors are present only at rest, and they disappear while performing an action (unlike essential tremors, which get worse on performing an action).


I am a Neurologist by profession and have been dealing with people suffering from various neurological disorders for the past 20 years. As a doctor, we see various emotions from close quarters. Seeing a smile on our patient’s face gives us immense satisfaction.

This blog is all about sharing my experiences as a doctor. General public can get insights into preventive and treatment aspects of various neuro-related illnesses. Healthcare professionals can also learn about neurological disorders, which would make them more efficient.

Dr Sudhir Kumar MD (Internal Medicine), DM (Neurology)