Why are some people well with CADASIL until their seventies whereas others present with symptoms much earlier?
The severity of CADASIL can vary widely within families. For example, within one family one member may have strokes in their forties or fifties whilst another may still be well when they are seventy. We do not fully understand why this is the case. Our research has shown that common risk factors such as smoking and high blood pressure make stroke occur earlier in patients with CADASIL, but this does not fully account for the differences within families. Other unknown factors also contribute. There is some evidence that genes other than the NOTCH3 gene may alter the severity of the disease and we are carrying out research trying to identify which these genes are.
How do I distinguish between a migraine attack and a TIA/mini stroke?
Migraine attacks are usually accompanied by headache, a feeling of sickness, and often intolerance of bright light. In CADASIL migraine attacks are also usually accompanied by an aura. The aura can be visual (often bright or coloured lights), sensory (often a feeling of tingling), speech (often the inability to find words), confusion, and loss of power in an arm or leg.
Sometimes it can be difficult to distinguish an aura which can occur without headache, from a mini stroke. In a mini stroke in CADASIL the most common symptoms are loss of power down one side of the body, or loss of sensation down one side of the body. The abnormality tends to on at the same time in both the arm and leg. Visual symptoms and inability to find the right words do not occur in CADASIL stroke.
Sometimes loss of power and an abnormal sensation can be difficult to differentiate between TIA and migraine, but a helpful pointer is that the symptoms in migraine often occur in one part of the body (for example, the face) and then spread gradually to other parts (for example, the arm), whereas in stroke they all come on at the same time. Also migraine symptoms are often possible (e.g. a tingling) whereas in stroke symptoms are usually negative (e.g. an inability to feel).
Is one’s gait affected in CADASIL as it progresses?
Gait can be affected in CADASIL. If a CADASIL patient has a stroke then they can have a limp secondary to weakness. However, gait can occasionally be affected without a stroke in a syndrome called gait apraxia. This is where disruption of connections within the white matter in the brain alters the ability to coordinate one’s walking. This can result in an unsteady and wide based gait or sometimes an abnormal gait due to small steps.