A.S. is a fiercely independent 68-year-old woman who loved driving around in her Jaguar and visiting glitzy casinos in Las Vegas. But one day, the vivacious and strong-willed woman (whose full name has been withheld for reasons of patient confidentiality) woke from a nap to an altered world.
Her home in a Chicago suburb had suddenly become an alien place - one where her doors and cabinets had somehow melted into the walls so that she could not find them. The right side of her body felt weaker after the nap, but that was less worrying than her inability to make sense of her home.
She thought that her eyesight had gone awry, so she tried to call her ophthalmologist for an appointment. But she could not dial the numbers on her phone. Luckily, her husband Michael was on hand to help. Eventually, she got an appointment. After a check-up, her ophthalmologist concluded that she had near-perfect eyesight, and her ailment was likely neurological.
He sent her away with a referral to a neurologist, and a multitude of questions swimming in her head. Several more months of frustration followed as neurologist after neurologist failed to give a satisfactory explanation for her strange symptoms. A.S. found that not only could she not distinguish between walls and doors, her hand-eye co-ordination was completely dysfunctional. Although she could see a pen on the floor, her hands would end up grasping at air when she reached for it.
As such, simple daily activities became Olympian challenges. A.S. could hardly brush her teeth at first, as her hands did not seem to know how to hold a toothbrush. She could not even bring the toothbrush to her mouth. Even walking became a potentially dangerous activity, and every step was an act of faith. While A.S. knew that the floor was there, she could not perceive it - or any obstacles - properly with her eyes. A misstep in the shower left her with two broken vertebrae.
But A.S. was uncommonly tenacious. She was determined to hold on to as much of her independence as possible. For one thing, she held out against selling her Jaguar for six months, even after it became painfully apparent that she would not drive again.
She also found ways to cope. When it came to brushing her teeth, A.S. started placing the toothpaste in her mouth and then attempting to bring the toothbrush to her teeth, taking care not to poke her eyes or ears in the process. She also held on to the sink to help orientate her. When she showered, she used a shower bar.
A.S.'s indomitable spirit showed in the way she chose to walk - marching forward independently and unflinchingly, even though she was terrified of falling - and horrified her husband with her nerve. Her unyielding search for answers eventually led her to the office of Dr Jose Biller, chairman of the department of neurology at the Loyola University Hospital in Illinois, US.
Biller ran a series of tests on A.S., one of which was to have her use her eyes to follow his finger as he moved it slowly back and forth in front of her. She could not do so, indicating that she had oculomotor apraxia, whereby she had lost control over the muscles controlling her eye movements. Next, he showed her a diagnostic picture of a thief stealing a cookie from a cookie jar in a kitchen. A.S. could not perceive the picture in its entirety, and she could only focus on limited elements in the picture at a time - a condition called simultanagnosia.
Dr Jason Cuomo, a third year student at Loyola University Chicago Stritch School of Medicine who studies under Biller, says that the condition is such that if A.S. were in a room and a tiger walked in the door, she might not be able to perceive the tiger in the conscious part of her brain. But her "reptilian" brain will still register the danger, and she would still feel terror but would not be able to immediately understand why she was scared.
Cuomo cites another example of what A.S.'s experience might be like: while she might not see a ball being thrown at her, her hand might move up in an attempt to block or catch the ball. Parts of her brain were still receiving and processing the visual input, but the conscious part of her mind could not. The different parts of the brain were not able to communicate to give her a complete perception and understanding of her environment.
Biller also found that A.S. has optic ataxia, meaning she cannot reach for objects using guidance from her eyes - as Cuomo put it, her visual input is faulty and unusable. An object that is 15 centimetres away might look like it was three metres away to her. This explains why she cannot perceive the floor, pick up a pen, or even put the toothbrush to her teeth.
A.S. was having to rely on her sense of touch, smell and sound to find out information about her surroundings. When Cuomo suggested that she cut out the erroneous input by closing her eyes, she refused. Seeing a distorted world was better than not seeing at all.
Based on her triad of symptoms, Biller suspected that A.S. had Balint's syndrome, a rare, debilitating condition likely caused by a series of strokes that damage approximately the same areas in both hemispheres of the brain.
Magnetic Resonance Imaging (MRI) scans showed that cells had died in the parietal and occipital parts of her brain, thereby confirming the diagnosis. The parietal cortex helps the body make planned movements by processing sensory input about its location and objects in its surrounding. The occipital lobe is the visual processing centre of the brain.
The damage is irreversible and so A.S. will have to live with Balint's syndrome for the rest of her life.
But the feisty woman is not about to let a rare and incurable condition dampen her zest for life, and she continues to find ways to adapt.
For instance, she found that she could see yellow very well, so her sons put yellow tape around the edges of doors and objects to help her navigate her home better. Although she can no longer read, she takes pleasure in listening to audio books.
Now A.S. has her sights trained on indulging in some of life's little extravagances.
She is planning to enjoy herself with a much-anticipated trip back to Las Vegas.