He shaved only half his face for 2 days. Neurologist shares why his patient's brain ignored the other side

A seemingly simple grooming habit turned into a striking medical mystery that has now captured widespread attention online. A man shaving only half his face might sound like an absent-minded moment, but in this case, it pointed to something far more serious happening inside the brain. The story, shared by a Hyderabad neurologist, reveals how subtle behavioural changes can signal deeper neurological conditions, offering a powerful reminder of how the brain shapes our perception of reality in ways we often take for granted.

Dr Sudhir Kumar, a neurologist, took to X and described the case of a 65-year-old man who was brought in for what appeared to be unusual behaviour over two days. The man consistently shaved only the right half of his face, responded only when spoken to from the right side, and even wore only the right half of his clothes without assistance. Alongside these behaviours, he showed mild weakness on the left side of his body. What made the case more complex was that when questioned, the patient denied having any problem at all. His medical history included diabetes and hypertension, both known risk factors for neurological events.

The diagnosis?

According to Dr Sudhir Kumar, this was a classic presentation of hemispatial neglect caused by a lesion in the non-dominant, usually right, parietal lobe of the brain. In such cases, the individual does not lose physical ability in the usual sense but instead loses awareness of one side of space. The patient behaves as though the left half of the world simply does not exist.

Key clues of the condition

He explained that key clues in this condition include ignoring the left side during daily activities such as shaving or dressing, responding only to stimuli coming from the right side, and showing mild left-sided weakness. Another important feature is anosognosia, where the patient is unaware of or denies their own deficit, making diagnosis even more challenging.

Dr Sudhir Kumar further highlighted that this is not a primary motor or sensory deficit but rather an attention disorder. The right parietal cortex plays a crucial role in directing attention to both sides of space, and when it is damaged, this balance is disrupted. Interestingly, left-sided neglect tends to be more severe than right-sided neglect because of the right hemisphere’s dominance in spatial awareness. Such conditions are often linked to infarcts in the right middle cerebral artery territory.

He also pointed out practical examination indicators, often referred to as exam pearls in medical training. Observing a patient shaving only half their face should immediately raise suspicion of neglect. A patient denying any deficit suggests anosognosia linked to right parietal damage. Difficulty in dressing one side of the body may indicate dressing apraxia.

As a clinical tip, Dr Sudhir Kumar emphasised the importance of actively testing for neglect. Simple tasks such as asking a patient to draw a clock or bisect a line can reveal the condition, as patients typically ignore the left side entirely during these exercises.