Page 37 - Handbook of Electronic Assistive Technology

24 HANDBOOK OF ELECTRONIC ASSISTIVE TECHNOLOGY

weakness, stiffness, wasting and painful spasms are seen. Problems with walking are
often the first signs. Normally, death comes within 3–5 years from involvement of the
diaphragm and other respiratory muscles, though some affected individuals live with
the condition for much longer. A juvenile form is also seen.
• Primary lateral sclerosis (UMN) is a rarer form, which progresses more slowly from
lower limb weakness to clumsiness and speech problems. Life expectancy is around
10–20 years after presentation and as this is generally late in life it may primarily be a
problem with quality rather than quantity of life.
• Progressive muscular atrophy (LMN) is a rarer form, which is slower in progression.
It normally presents with clumsiness, cramps and weakness, particularly in the upper
limb.
• Progressive bulbar palsy (LMN) mainly affects the lower motor neurons in the brain
stem. As such the degeneration affects the muscles of the face, mouth, throat and
tongue. Progressive expressive speech difficulties and swallowing are often the first
signs; it is rapidly progressive with a life expectancy normally of around 6 months to
3 years. Pseudobulbar palsy (UMN) presents in a similar way but is a degeneration of
the upper motor neurons that transmit to the lower motor neurons (upper above, lower
below – though the symptoms are similar, it’s important for doctors).

Peripheral Nerve Problems
Problems within the peripheral nerves cause pain, flaccid weakness and sensory and auto-
nomic disorders (usually seen as sweatiness, paleness, redness, coolness, hotness and
even more pain).
Once again, they can be caused by local or shearing trauma, compression infection and
inflammation.
The best known of these is sciatica, one of a variety of conditions caused by spinal nerve
root compression from a herniated or slipped disc at any particular level, leading to pain
and sensory and movement problems. Groups of nerves can also be involved such as bra-
chial plexus injury (arm) and carpal tunnel (hand) syndrome.
Multiple peripheral nerves can be affected, sometimes genetic in origin (e.g., heredi-
tary motor and sensory neuropathies (HMSN)), sometimes reactive to body factors and
systemic disease (e.g., diabetic or cirrhotic polyneuropathies), sometimes inflammatory
(e.g., Guillain–Barré syndrome), sometimes infective (e.g., leprosy, mumps or diphtheria)
and sometimes toxic (e.g., ethanol, lead or some drugs).
Hereditary polyneuropathies are generally slowly progressive. The commonest is
HMSN type I Charcot–Marie–Tooth disease. Motor, sensory and autonomic components
are seen dependent on which pattern of peripheral nerves is involved.

Muscle Problems
MYOPATHIES
Myopathies cause weakness because of defects in the structure and function of muscle
fibres. This has a wide variety of potential causes both primary, i.e., dependent on a disease