Unawareness of motor deficit in Huntington's disease

Unawareness of chorea is well-known in Huntington's disease (HD). This study investigated unawareness for the whole gamut of motor impairments in daily life, which has not been explored previously.

Data from 71 consecutive patients with stage I or II HD were assessed retrospectively. The motor section of UHDRS; the total functional capacity; a short battery of cognitive tests; the SANS and SAPS scales for negative and positive psychiatric symptoms; the Hamilton scales for depression (HAM-D) and anxiety (HAM-A); and a semi-structured questionnaire to assign motor anosognosia on a scale from 0 (fully aware) to 3 (severely unaware), were administered.

Twenty-seven (38%) patients were aware of their motor symptoms, and 44 (62%) were unaware: 29/44 (66%) score 1, 11 (25%) score 2, and 4 (9%) score 3. When their motor deficits were pointed out, the severely unaware patients insisted on having no impairments contrary to all evidence. Unaware patients performed worse on the visual search test (p = 0.04) and SANS (apathy) (p = 0.02) than aware patients. Comparison between the three groups defined by anosognosia scores 0, 1, and 2 + 3, showed that SANS (p = 0.04) and HAM-A (p = 0.036) differed significantly between the groups, with apathy increasing and anxiety reducing with worsening anosognosia. Furthermore, anosognosia score correlated directly with apathy (Spearman's rho = 0.311; p = 0.008) and indirectly with anxiety (rho= -0.288; p = 0.015), visual search (rho= -0.247; p = 0.038), and verbal fluency (rho= -0.243; p = 0.041).

Anosognosia in HD appears multifactorial: executive impairment, apathetic syndrome, and perhaps delusional ideation may contribute to its occurrence and severity.