A World Without Meaning

Winning the 2011 Society for Neuroscience Brain Awareness Video Contest this year is a heart-wrenching animated poem told with the voice of a 10-year old boy whose grandfather has suffered a stroke and developed aphasia, a language impairment. It’s called The Treasure Hunt and it does a wonderful job of humanizing and explaining the condition. Language is such a central part of our minds that it’s very difficult for most of us to imagine a world in which our capacity to talk and express ourselves using speech is stripped away.

Treasure_hunt


As the fall settles in, and the holiday season has officially kicked off with Canadian Thanksgiving, opera singers everywhere are performing superstitious rituals with the aim of fending off illnesses. Some rinse their sinuses with saline daily, others add honey to their tea in generous portions; everyone’s hands begin to dry up from the liberal application of sanitizing gels and the first sensation of an itchy throat sends us burrowing under our covers to nap the germs away. For a singer, losing one’s voice means losing work and opportunities to generate future work. Because our productivity and happiness depend on a healthy voice, and getting sick is relatively unpredictable and mysterious, we latch onto home remedies and folk wisdom more readily than the average Joe.

When we do get sick, however, we refrain from talking as much as possible and, for a short while, we glimpse a world in which speech is an inaccessible form of communication. Being theatrical people by nature, we rely more heavily on facial expressions and gestures. Individuals with aphasia are also encouraged to use other forms of communication such as writing, or gesturing or drawing to get their ideas and desires across.

But what if the very meaning of the words is what begins to deteriorate rather than the ability to form them? What does it feel like to lose concepts? If you no longer know that an eagle is an eagle and a mouse is a mouse, does the world seem full of wonder or mystery? The patients that I’ve been studying at UCSF are suffering from semantic dementia, a progressive degenerative brain disease that slowly erases their conceptual knowledge. A baby learns first that a bird is a type of animal, and then that an eagle is a type of bird: patients with semantic dementia first forget that eagles and hawks are different types of birds, and eventually they can’t distinguish a bird from another animal.Their loss follows the development of language in reverse.

Often, these patients choose to engage in activities that involve complex visual images as their disease progresses: they love working on jigsaw puzzles, playing solitaire on the computer, gardening, and some even begin to paint or sculpt works of art. My goal has been to try to understand the changes in the mind that lead to this paradoxical emergence of visual creativity. I’ve approached this question using the rigorous methods of neuroscience: tracking where patients look when they are viewing pictures or art work or searching for a specific target in a large array, comparing the brain volumes of patients with healthy counterparts and patients with other diseases and correlating these volumes with specific behavior, timing how long it takes them to find a target and how accurately they can perform a difficult visual search task. It turns out that they are faster and more accurate than healthy controls in tasks like ‘Where’s Waldo?’, and the brain regions that correlate with performance on those tasks are the same regions involved in grapheme-color synaesthesia, a condition in which people ‘see’ letters and numbers in color.

When a video like The Treasure Hunt puts the experience of aphasia into a simple and elegant poem, I can’t help but wonder what it must be like to experience the world through the lens of semantic dementia: when things lose their meaning, are they less distracting? Does the world become more vivid and alive? Many of their paintings seem to suggest that it does. And the fact that these patients find new ways of communicating underscores the central role that relationships and social interactions play in our lives. The holidays are designed to strengthen the ties that bind us to friends and family, and as the days get shorter and the nights grow colder, it’s as good a time as any to return those personal calls.