Huntington's Disease

Question 1

Describe characteristics of HD as an inherited disorder

Answer 1

1. Single genetic disorder: mutation of a single gene

2. Autosomal dominant disorder: each child with 50% chance

Question 2

average age of onset

Answer 2

40.8 years (mid-life)

Question 3

Triad of Symptoms

Answer 3

1. cognitive impairments (working memory, organization, cognition, executive functioning, etc)
2. Psychiatric impairments (irritability, depression, anxiety, aggregation)
3. Movement disorder (chorea, bradkykinesia, dystonia, dyscoordination, balance, gait)

Question 4

Neuropathology of HD

Answer 4

Chromosome 4 –> excessive “CAG” repeat sequence
causes destruction of medium spiny neurons in striatum –> decreased activity of indirect pathway –> lack of inhibition in thalamo-cortical activity (movement)
*length of CAG sequence = associated with age of onset
*>40 CAG = HD (normal is

Question 5

Cell death measured on MRI

Answer 5

increase in ventricular space

decrease in striatal volume

Question 6

Diagnosis of HD

Answer 6

related to motor impairments that are unequivically HD

made with detailed motor exam looking at eye movements, tongue movements, gait, and balance

Question 7

Stages of HD

Answer 7

Stage 1 (TFC 11-13)
Stage 2 (TFC 7-10)
Stage 3 (TFC 3-10) *unable to work, need help with some ADLs
Stage 4 (TFC 1-2)
Stage 5 (TFC 0)*essentially dependent on caregiver

TFC scale: 0-13, 13 = complete functional capacity, 0=no functional capacity

Question 8

Participation assessments in HD

Answer 8

SF-36

WHO-QOL

Question 9

Activity assessments in HD

Answer 9

6MWT
10MRW
TUG
Barthel Indedx
ABC scale
UHDRS-TFC

Question 10

Body Function assessments in HD

Answer 10

BBS
Tinetti POMA
DGI
Manual Ability Measure
Strength
UHDRS

Question 11

Changes in barin volume

Answer 11

Those with diagnosis of HD have a much steeper slope of brain volume decreased over time
*brain volume decrease occurs before diagnosis

Question 12

Chorea and voluntary movements

Answer 12

Chorea tapers off as time progresses (turns to rigidity)

Voluntary movements continue to increase with time

Question 13

Gait and falls

Answer 13

increase in stride length variability- associated with greater incidence of falls

Question 14

Clinical measures validated for balance impairments in HD

Answer 14

TUG and BBS

Question 15

Effects of structured exercise programs on pts with HD

Answer 15

• improvement in motor and core function, but lasts a shorter period of time
• delayed onset of impairments/delayed clinical diagnosis