Behavioural abnormalities contribute to functional decline in Huntington’s disease
1 Department of Neurosciences, University of California, San Diego, California, USA&5.(]c:, 百拇医药
2 Department of Family and Preventative Medicine, University of California, San Diego, California&5.(]c:, 百拇医药
3 Departments of Psychiatry and Neurology, The University of Iowa, Iowa City, Iowa, USA&5.(]c:, 百拇医药
ABSTRACT&5.(]c:, 百拇医药
The independent and relative contributions of motor, cognitive, and behavioural deficits to functional decline in patients with Huntington’s disease are examined. Twenty two patients with Huntington’s disease were assessed with rating scales for motor dysfunction, cognitive measures of executive functions, and behavioural measures of apathy, executive dysfunction, and disinhibition. Their functional status was assessed with informant based and clinician based ratings of activities of daily living (ADL). A composite apathy/executive dysfunction behavioural index was strongly related to decline in ADL independently and after controlling for motor and cognitive deficits. These results suggest that behavioural dysfunction contributes to functional decline in patients with Huntington’s disease and may impede their ability to utilise motor or cognitive skills that remain available in the early stages of the disease.
Keywords: Huntington’s disease; behavioural dysfunction; activities of daily living;ix, 百拇医药
Abbreviations: ADL, activities of daily living; BDI, Beck depression inventory; CANTAB, Cambridge neuropsychological test automated battery; FLOPS, frontal lobe personality scale; HD-ADL, Huntington’s disease activities of daily living scale; TFC, total functional capacity scale; UHDRS, unified Huntington’s disease rating scale;ix, 百拇医药
Huntington’s disease is a genetically transmitted neurodegenerative disease that results in a severe movement disorder (chorea, dystonia, bradykinesia, and oculomotor deficits) because of atrophy of the basal ganglia1 and related brain structures.2 The movement disorder is accompanied by notable cognitive impairment (for example, executive dysfunction) and behavioural changes such as depression, irritability, apathy, and inflexibility.3 In some combination, the triad of motor, cognitive, and behavioural deficits associated with Huntington’s disease contributes to profound functional decline with a gradual loss of independence in performing the usual activities of daily living (ADL).
Previous studies have shown that the severity of functional impairment in patients with Huntington’s disease is at least moderately related to the severity of their motor and cognitive dysfunction.4–6 However, these factors account for only a portion of the variance in ADL decline, and additional variance might be explained by the behavioural abnormalities that occur in the disease. The profound apathy, lack of initiative, and irritability shown by some patients with Huntington’s disease may interfere with their ability to perform certain ADL, even though they retain the necessary motor and cognitive capacity.w!6;/&, http://www.100md.com
To address this issue, we examined the relation between functional disability and motor, cognitive, and behavioural deficits in individuals with Huntington’s disease. We hypothesised that disease related changes in behaviour would significantly influence ratings of functional capacity even after the effects of motor and cognitive deficits were taken into account.
METHODS:krm, 百拇医药
Participants:krm, 百拇医药
The participants were 22 patients with Huntington’s disease (13 women, 9 men) who had an informant available to complete behavioural and functional ratings. All patients were recruited from the Huntington’s Disease Centers of Excellence at the University of California, San Diego (UCSD) (n = 16) or the University of Iowa (n = 6). The institutional review boards at each institution approved all the procedures. Written consent was obtained from the participants after the study was fully explained to them.:krm, 百拇医药
The subjects had a positive family history of Huntington’s disease or a positive genetic test for the mutation, and presented with at least one major neurological sign of the disease (chorea or dystonia) on the unified Huntington’s disease rating scale (UHDRS).7 Mean (SD) age of the participants was 46.3 (8.4) years, and they had 13.9 (2.0) years of education, an estimated premorbid IQ of 112.5 (9.9), and a Mattis dementia rating scale (DRS) score of 120.0 (13.2), which is indicative of mild to moderate dementia. English was the first language of all the patients. Most were classified as having no (n = 12) or minimal (n = 4) depressive symptoms, according to the Beck depression inventory (BDI); however, a subset had mild to moderate (n = 2), moderate to severe (n = 1), or severe (n = 3) depressive symptoms. Many of the patients were taking antidepressants (n = 12), neuroleptics, (n = 7), anticonvulsants (n = 4), or anxiolytics (n = 3), either alone or in combination. No patient had a reported history of stroke, brain tumour, brain surgery, head injury with loss of consciousness for more than five minutes, or substance abuse/dependence within the past year.
Procedureslny)$ev, 百拇医药
Motor assessmentlny)$ev, 百拇医药
The severity of motor dysfunction was assessed using the motor examination from the UHDRS.7 Total scores range between 0 and 124, with higher scores signifying greater motor dysfunction.lny)$ev, 百拇医药
Cognitive testinglny)$ev, 百拇医药
The pattern recognition, spatial recognition, spatial span, and spatial working memory subtests of the Cambridge neuropsychological test automated battery (CANTAB) were administered according to the standard test protocol.8 A CANTAB cognitive composite score was derived by computing z scores for each of the four subtests and averaging across the four scores. The controlled oral word association test and the symbol digit modalities test from the UHDRS were also administered and a composite UHDRS cognitive z score derived.lny)$ev, 百拇医药
Behavioural ratingslny)$ev, 百拇医药
The frontal lobe personality scale (FLOPS) was completed by an informant who had at least daily contact with the patient. The FLOPS is a 46 item questionnaire for identifying the types of behavioural change commonly associated with frontal lobe damage.9 Three subscales are derived: apathy, executive dysfunction, and disinhibition. To correct for different numbers of items in the three subscales, a behavioural "change ratio" was computed for each by dividing the difference between ratings of predisease and current behaviour by the number of subscale items. Change ratios increased with increasing occurrence of behavioural problems.
Functional ratingswk{67, http://www.100md.com
The same informant who completed the FLOPS also completed the Huntington’s disease activities of daily living scale (HD-ADL).10 The HD-ADL scale was divided into separate instrumental (for example, communication, finances) and physical (eating, dressing) ADL subscales. The Shoulson–Fahn total functional capacity scale (TFC) from the UHDRS was also completed by a clinician.wk{67, http://www.100md.com
RESULTSwk{67, http://www.100md.com
Values are given as mean (SD) throughout. The average UHDRS motor score (mean = 29.9 (20.8)), the CANTAB composite score (mean z score = -1.5 (1.3)), the UHDRS composite score (mean z score = -2.0 (1.1)), the TFC (mean = 8.7 (3.9)), and instrumental (mean = 60.6 (28.5)%) and physical (mean = 77.3 (22.6)%) HD-ADL scores were indicative of mild to moderate impairment. Change scores for the FLOPS subscales differed significantly from zero (p values < 0.001; indicating worsening behaviour), with the apathy score (mean = 1.2 (0.7)) greater than the executive dysfunction score (mean = 0.9 (0.7); p < 0.05) and the executive dysfunction score greater than the disinhibition score (mean = 0.5 (0.5); p < 0.01). For remaining analyses apathy and executive dysfunction subscales were combined because they were highly correlated (r = 0.83, p < 0.001).
The disinhibition subscale was not significantly correlated with any of the three functional measures (instrumental HD-ADL, r = -0.17; physical HD-ADL, r = 0.07; TFC, r = 0.09). In contrast, the apathy/executive score was highly related to the scores obtained on the instrumental HD-ADL (r = -0.92), the physical HD-ADL (r = -0.83), and the TFC (r = -0.77) functional measures (all p values < 0.001; ).).t(*15, http://www.100md.com
fig.ommitted).t(*15, http://www.100md.com
Scatterplots showing the relation between the apathy/executive dysfunction composite change ratio (apathy/executive score) and percentage scores on the Huntington’s disease activities of daily living (HD-ADL) instrumental (top) and physical (middle) subscales and the total functional capacity scale (bottom).).t(*15, http://www.100md.com
Multiple regression analyses showed that a combination of the motor score, the CANTAB cognitive score, and the apathy/executive score accounted for 91% of the variance in the instrumental HD-ADL score (adjusted R2 = 0.90; p < 0.001), 83% of the variance in the physical HD-ADL score (adjusted R2 = 0.80; p < 0.001), and 82% of the variance in TFC score (adjusted R2 = 0.79; p < 0.001).
The unique variance in function explained by each variable was then determined after controlling for the variance accounted for by both of the other two variables. The apathy/executive score accounted for significantly more unique variance in the instrumental HD-ADL scores than did the motor score (36% v 3% (95% confidence interval 6% to 63%)) or the CANTAB cognitive score (36% v < 1% (9% to 67%)). There was no significant difference in the percentage of variance in physical HD-ADL or TFC scores explained by the behavioural, motor, and cognitive scores.-@j[, http://www.100md.com
fig.ommitted-@j[, http://www.100md.com
Unique variance in function explained by performance on the behavioural, cognitive, or motor measure after controlling for the variance accounted for by performance on both of the other two measures (R2change)-@j[, http://www.100md.com
Similar multiple regression analyses using the UHDRS cognitive score instead of the CANTAB cognitive score showed that the motor score, the cognitive score, and the apathy/executive score accounted for 92% of the variance in the instrumental HD-ADL score (adjusted R2 = 0.90; p < 0.001), 84% of the variance in the physical HD-ADL score (adjusted R2 = 0.81; p < 0.001), and 84% of the variance in TFC score (adjusted R2 = 0.81; p < 0.001). Additional analyses showed that the apathy/executive score accounted for significantly more unique variance in the instrumental HD-ADL scores than did the UHDRS cognitive score (18% v 1% (3% to 37%)). No other comparisons were significantly different.
DISCUSSION2jv.a'%, http://www.100md.com
Our results show that a composite behavioural index of apathy/executive dysfunction in patients with Huntington’s disease is strongly related to informant based or clinician based ratings of decline in their everyday activities. This behavioural measure accounted for a significant amount of unique variance in the ADL measures even after controlling for the effects of motor and cognitive deficits, and this remained the case even if instrumental or physical ADL were considered separately. Thus behavioural dysfunction may be quite disabling in patients with Huntington’s disease and could impede their ability to utilise motor or cognitive skills that may still be available in the early stages of the disease.2jv.a'%, http://www.100md.com
Apathy was the most significant behavioural abnormality to develop in patients with Huntington’s disease, consistent with a previous finding of apathy in roughly 50% of affected patients who were assessed with the neuropsychiatric inventory.11 This does not appear to be a reflection of depression as there was no significant relation between scores on the BDI and the FLOPS apathy subscale (or any other subscale) in the present study (r = 0.18, p > 0.4) or in a previous study with a larger sample of Huntington’s disease patients.12 Rather, the frontostriatal neuropathology that occurs in Huntington’s disease13 appears to lead to a primary reduction in drive and motivation that is manifested as behavioural apathy.
Conclusions7-6\', 百拇医药
Behavioural dysfunction makes an important contribution to the decline in everyday functioning in patients with Huntington’s disease, and a full accounting of the antecedents of their functional decline must consider the interaction between motor, cognitive, and behavioural impairment. Although this conclusion must be generalised cautiously because of the relatively small sample size and the retrospective nature of the behavioural ratings, our results underscore the value of assessing behavioural change in Huntington’s disease.7-6\', 百拇医药
ACKNOWLEDGEMENTS7-6\', 百拇医药
Supported by NIMH grant R03 MH59430 and NIH grant P50 AG05131 to the University of California at San Diego (UCSD); NIMH grants K02 MH01579, R29 MH55331, and NINDS grant R01 NS40068 to the University of Iowa; and Center of Excellence Awards from the Huntington’s Disease Society of America to UCSD and the University of Iowa.7-6\', 百拇医药
REFERENCES
Vonsattel JP, Myers RH, Stevens TJ, et al. Neuropathological classification of Huntington’s disease. J Neuropathol Exp Neurol 1985;44:559–77.1, 百拇医药
Aylward EH, Anderson NB, Bylsma FW, et al. Frontal lobe volume in patients with Huntington’s disease. Neurology 1998;50:252–8.1, 百拇医药
Folstein SE. Huntington’s disease: a disorder of families. Baltimore: Johns Hopkins University Press, 1989.1, 百拇医药
Young AB, Penney JB, Starosta-Rubinstein S, et al. PET scan investigations of Huntington’s disease: cerebral metabolic correlates of neurological features and functional decline. Ann Neurol 1986; 20:296–303.1, 百拇医药
Bamford KA, Caine ED, Kido DK, et al. Clinical-pathologic correlation in Huntington’s disease: a neuropsychological and computed tomography study. Neurology 1989;39:796–801.1, 百拇医药
Rothlind JC, Bylsma FW, Peyser C, et al. Cognitive and motor correlates of everyday functioning in early Huntington’s disease. J Nerv Ment Dis 1993;181:194–9.
Huntington Study Group. Unified Huntington’s disease rating scale: reliability and consistency. Mov Disord 1996;11:136–42.a$up$[, http://www.100md.com
Owen AM, Downes JJ, Sahakian BJ, et al. Planning and spatial working memory following frontal lobe lesions in man. Neuropsychologia 1990;28:1021–34.a$up$[, http://www.100md.com
Grace J, Stout JC, Malloy PF. Assessing frontal lobe behavioral syndromes with the frontal lobe personality scale. Assessment 1999;6:269–84.a$up$[, http://www.100md.com
Bylsma FW, Rothlind JC, Hall MR, et al. Assessment of adaptive functioning in Huntington’s disease. Mov Disord 1993;8:183–90.a$up$[, http://www.100md.com
Paulsen JS, Ready RE, Hamilton JM, et al. Neuropsychiatric aspects of Huntington’s disease. J Neurol Neurosurg Psychiatry 2001;71:310–14.a$up$[, http://www.100md.com
Levy ML, Cummings JL, Fairbanks LA, et al. Apathy is not depression. J Neuropsychiatry Clin Neurosci 1998;10:314–19.a$up$[, http://www.100md.com
Alexander GE, Crutcher MD. Functional architecture of basal ganglia circuits: neural substrates of parallel processing. Trends Neurosci 1990;13:266–71.a$up$[, http://www.100md.com
Efron B. Bootstrap methods: another look at the jackknife. Ann Stat 1979;7:1–26.(J M Hamilton D P Salmon J Corey-Bloom A Gamst J S Paulsen S Jerkins M W Jacobson and G Peavy)
2 Department of Family and Preventative Medicine, University of California, San Diego, California&5.(]c:, 百拇医药
3 Departments of Psychiatry and Neurology, The University of Iowa, Iowa City, Iowa, USA&5.(]c:, 百拇医药
ABSTRACT&5.(]c:, 百拇医药
The independent and relative contributions of motor, cognitive, and behavioural deficits to functional decline in patients with Huntington’s disease are examined. Twenty two patients with Huntington’s disease were assessed with rating scales for motor dysfunction, cognitive measures of executive functions, and behavioural measures of apathy, executive dysfunction, and disinhibition. Their functional status was assessed with informant based and clinician based ratings of activities of daily living (ADL). A composite apathy/executive dysfunction behavioural index was strongly related to decline in ADL independently and after controlling for motor and cognitive deficits. These results suggest that behavioural dysfunction contributes to functional decline in patients with Huntington’s disease and may impede their ability to utilise motor or cognitive skills that remain available in the early stages of the disease.
Keywords: Huntington’s disease; behavioural dysfunction; activities of daily living;ix, 百拇医药
Abbreviations: ADL, activities of daily living; BDI, Beck depression inventory; CANTAB, Cambridge neuropsychological test automated battery; FLOPS, frontal lobe personality scale; HD-ADL, Huntington’s disease activities of daily living scale; TFC, total functional capacity scale; UHDRS, unified Huntington’s disease rating scale;ix, 百拇医药
Huntington’s disease is a genetically transmitted neurodegenerative disease that results in a severe movement disorder (chorea, dystonia, bradykinesia, and oculomotor deficits) because of atrophy of the basal ganglia1 and related brain structures.2 The movement disorder is accompanied by notable cognitive impairment (for example, executive dysfunction) and behavioural changes such as depression, irritability, apathy, and inflexibility.3 In some combination, the triad of motor, cognitive, and behavioural deficits associated with Huntington’s disease contributes to profound functional decline with a gradual loss of independence in performing the usual activities of daily living (ADL).
Previous studies have shown that the severity of functional impairment in patients with Huntington’s disease is at least moderately related to the severity of their motor and cognitive dysfunction.4–6 However, these factors account for only a portion of the variance in ADL decline, and additional variance might be explained by the behavioural abnormalities that occur in the disease. The profound apathy, lack of initiative, and irritability shown by some patients with Huntington’s disease may interfere with their ability to perform certain ADL, even though they retain the necessary motor and cognitive capacity.w!6;/&, http://www.100md.com
To address this issue, we examined the relation between functional disability and motor, cognitive, and behavioural deficits in individuals with Huntington’s disease. We hypothesised that disease related changes in behaviour would significantly influence ratings of functional capacity even after the effects of motor and cognitive deficits were taken into account.
METHODS:krm, 百拇医药
Participants:krm, 百拇医药
The participants were 22 patients with Huntington’s disease (13 women, 9 men) who had an informant available to complete behavioural and functional ratings. All patients were recruited from the Huntington’s Disease Centers of Excellence at the University of California, San Diego (UCSD) (n = 16) or the University of Iowa (n = 6). The institutional review boards at each institution approved all the procedures. Written consent was obtained from the participants after the study was fully explained to them.:krm, 百拇医药
The subjects had a positive family history of Huntington’s disease or a positive genetic test for the mutation, and presented with at least one major neurological sign of the disease (chorea or dystonia) on the unified Huntington’s disease rating scale (UHDRS).7 Mean (SD) age of the participants was 46.3 (8.4) years, and they had 13.9 (2.0) years of education, an estimated premorbid IQ of 112.5 (9.9), and a Mattis dementia rating scale (DRS) score of 120.0 (13.2), which is indicative of mild to moderate dementia. English was the first language of all the patients. Most were classified as having no (n = 12) or minimal (n = 4) depressive symptoms, according to the Beck depression inventory (BDI); however, a subset had mild to moderate (n = 2), moderate to severe (n = 1), or severe (n = 3) depressive symptoms. Many of the patients were taking antidepressants (n = 12), neuroleptics, (n = 7), anticonvulsants (n = 4), or anxiolytics (n = 3), either alone or in combination. No patient had a reported history of stroke, brain tumour, brain surgery, head injury with loss of consciousness for more than five minutes, or substance abuse/dependence within the past year.
Procedureslny)$ev, 百拇医药
Motor assessmentlny)$ev, 百拇医药
The severity of motor dysfunction was assessed using the motor examination from the UHDRS.7 Total scores range between 0 and 124, with higher scores signifying greater motor dysfunction.lny)$ev, 百拇医药
Cognitive testinglny)$ev, 百拇医药
The pattern recognition, spatial recognition, spatial span, and spatial working memory subtests of the Cambridge neuropsychological test automated battery (CANTAB) were administered according to the standard test protocol.8 A CANTAB cognitive composite score was derived by computing z scores for each of the four subtests and averaging across the four scores. The controlled oral word association test and the symbol digit modalities test from the UHDRS were also administered and a composite UHDRS cognitive z score derived.lny)$ev, 百拇医药
Behavioural ratingslny)$ev, 百拇医药
The frontal lobe personality scale (FLOPS) was completed by an informant who had at least daily contact with the patient. The FLOPS is a 46 item questionnaire for identifying the types of behavioural change commonly associated with frontal lobe damage.9 Three subscales are derived: apathy, executive dysfunction, and disinhibition. To correct for different numbers of items in the three subscales, a behavioural "change ratio" was computed for each by dividing the difference between ratings of predisease and current behaviour by the number of subscale items. Change ratios increased with increasing occurrence of behavioural problems.
Functional ratingswk{67, http://www.100md.com
The same informant who completed the FLOPS also completed the Huntington’s disease activities of daily living scale (HD-ADL).10 The HD-ADL scale was divided into separate instrumental (for example, communication, finances) and physical (eating, dressing) ADL subscales. The Shoulson–Fahn total functional capacity scale (TFC) from the UHDRS was also completed by a clinician.wk{67, http://www.100md.com
RESULTSwk{67, http://www.100md.com
Values are given as mean (SD) throughout. The average UHDRS motor score (mean = 29.9 (20.8)), the CANTAB composite score (mean z score = -1.5 (1.3)), the UHDRS composite score (mean z score = -2.0 (1.1)), the TFC (mean = 8.7 (3.9)), and instrumental (mean = 60.6 (28.5)%) and physical (mean = 77.3 (22.6)%) HD-ADL scores were indicative of mild to moderate impairment. Change scores for the FLOPS subscales differed significantly from zero (p values < 0.001; indicating worsening behaviour), with the apathy score (mean = 1.2 (0.7)) greater than the executive dysfunction score (mean = 0.9 (0.7); p < 0.05) and the executive dysfunction score greater than the disinhibition score (mean = 0.5 (0.5); p < 0.01). For remaining analyses apathy and executive dysfunction subscales were combined because they were highly correlated (r = 0.83, p < 0.001).
The disinhibition subscale was not significantly correlated with any of the three functional measures (instrumental HD-ADL, r = -0.17; physical HD-ADL, r = 0.07; TFC, r = 0.09). In contrast, the apathy/executive score was highly related to the scores obtained on the instrumental HD-ADL (r = -0.92), the physical HD-ADL (r = -0.83), and the TFC (r = -0.77) functional measures (all p values < 0.001; ).).t(*15, http://www.100md.com
fig.ommitted).t(*15, http://www.100md.com
Scatterplots showing the relation between the apathy/executive dysfunction composite change ratio (apathy/executive score) and percentage scores on the Huntington’s disease activities of daily living (HD-ADL) instrumental (top) and physical (middle) subscales and the total functional capacity scale (bottom).).t(*15, http://www.100md.com
Multiple regression analyses showed that a combination of the motor score, the CANTAB cognitive score, and the apathy/executive score accounted for 91% of the variance in the instrumental HD-ADL score (adjusted R2 = 0.90; p < 0.001), 83% of the variance in the physical HD-ADL score (adjusted R2 = 0.80; p < 0.001), and 82% of the variance in TFC score (adjusted R2 = 0.79; p < 0.001).
The unique variance in function explained by each variable was then determined after controlling for the variance accounted for by both of the other two variables. The apathy/executive score accounted for significantly more unique variance in the instrumental HD-ADL scores than did the motor score (36% v 3% (95% confidence interval 6% to 63%)) or the CANTAB cognitive score (36% v < 1% (9% to 67%)). There was no significant difference in the percentage of variance in physical HD-ADL or TFC scores explained by the behavioural, motor, and cognitive scores.-@j[, http://www.100md.com
fig.ommitted-@j[, http://www.100md.com
Unique variance in function explained by performance on the behavioural, cognitive, or motor measure after controlling for the variance accounted for by performance on both of the other two measures (R2change)-@j[, http://www.100md.com
Similar multiple regression analyses using the UHDRS cognitive score instead of the CANTAB cognitive score showed that the motor score, the cognitive score, and the apathy/executive score accounted for 92% of the variance in the instrumental HD-ADL score (adjusted R2 = 0.90; p < 0.001), 84% of the variance in the physical HD-ADL score (adjusted R2 = 0.81; p < 0.001), and 84% of the variance in TFC score (adjusted R2 = 0.81; p < 0.001). Additional analyses showed that the apathy/executive score accounted for significantly more unique variance in the instrumental HD-ADL scores than did the UHDRS cognitive score (18% v 1% (3% to 37%)). No other comparisons were significantly different.
DISCUSSION2jv.a'%, http://www.100md.com
Our results show that a composite behavioural index of apathy/executive dysfunction in patients with Huntington’s disease is strongly related to informant based or clinician based ratings of decline in their everyday activities. This behavioural measure accounted for a significant amount of unique variance in the ADL measures even after controlling for the effects of motor and cognitive deficits, and this remained the case even if instrumental or physical ADL were considered separately. Thus behavioural dysfunction may be quite disabling in patients with Huntington’s disease and could impede their ability to utilise motor or cognitive skills that may still be available in the early stages of the disease.2jv.a'%, http://www.100md.com
Apathy was the most significant behavioural abnormality to develop in patients with Huntington’s disease, consistent with a previous finding of apathy in roughly 50% of affected patients who were assessed with the neuropsychiatric inventory.11 This does not appear to be a reflection of depression as there was no significant relation between scores on the BDI and the FLOPS apathy subscale (or any other subscale) in the present study (r = 0.18, p > 0.4) or in a previous study with a larger sample of Huntington’s disease patients.12 Rather, the frontostriatal neuropathology that occurs in Huntington’s disease13 appears to lead to a primary reduction in drive and motivation that is manifested as behavioural apathy.
Conclusions7-6\', 百拇医药
Behavioural dysfunction makes an important contribution to the decline in everyday functioning in patients with Huntington’s disease, and a full accounting of the antecedents of their functional decline must consider the interaction between motor, cognitive, and behavioural impairment. Although this conclusion must be generalised cautiously because of the relatively small sample size and the retrospective nature of the behavioural ratings, our results underscore the value of assessing behavioural change in Huntington’s disease.7-6\', 百拇医药
ACKNOWLEDGEMENTS7-6\', 百拇医药
Supported by NIMH grant R03 MH59430 and NIH grant P50 AG05131 to the University of California at San Diego (UCSD); NIMH grants K02 MH01579, R29 MH55331, and NINDS grant R01 NS40068 to the University of Iowa; and Center of Excellence Awards from the Huntington’s Disease Society of America to UCSD and the University of Iowa.7-6\', 百拇医药
REFERENCES
Vonsattel JP, Myers RH, Stevens TJ, et al. Neuropathological classification of Huntington’s disease. J Neuropathol Exp Neurol 1985;44:559–77.1, 百拇医药
Aylward EH, Anderson NB, Bylsma FW, et al. Frontal lobe volume in patients with Huntington’s disease. Neurology 1998;50:252–8.1, 百拇医药
Folstein SE. Huntington’s disease: a disorder of families. Baltimore: Johns Hopkins University Press, 1989.1, 百拇医药
Young AB, Penney JB, Starosta-Rubinstein S, et al. PET scan investigations of Huntington’s disease: cerebral metabolic correlates of neurological features and functional decline. Ann Neurol 1986; 20:296–303.1, 百拇医药
Bamford KA, Caine ED, Kido DK, et al. Clinical-pathologic correlation in Huntington’s disease: a neuropsychological and computed tomography study. Neurology 1989;39:796–801.1, 百拇医药
Rothlind JC, Bylsma FW, Peyser C, et al. Cognitive and motor correlates of everyday functioning in early Huntington’s disease. J Nerv Ment Dis 1993;181:194–9.
Huntington Study Group. Unified Huntington’s disease rating scale: reliability and consistency. Mov Disord 1996;11:136–42.a$up$[, http://www.100md.com
Owen AM, Downes JJ, Sahakian BJ, et al. Planning and spatial working memory following frontal lobe lesions in man. Neuropsychologia 1990;28:1021–34.a$up$[, http://www.100md.com
Grace J, Stout JC, Malloy PF. Assessing frontal lobe behavioral syndromes with the frontal lobe personality scale. Assessment 1999;6:269–84.a$up$[, http://www.100md.com
Bylsma FW, Rothlind JC, Hall MR, et al. Assessment of adaptive functioning in Huntington’s disease. Mov Disord 1993;8:183–90.a$up$[, http://www.100md.com
Paulsen JS, Ready RE, Hamilton JM, et al. Neuropsychiatric aspects of Huntington’s disease. J Neurol Neurosurg Psychiatry 2001;71:310–14.a$up$[, http://www.100md.com
Levy ML, Cummings JL, Fairbanks LA, et al. Apathy is not depression. J Neuropsychiatry Clin Neurosci 1998;10:314–19.a$up$[, http://www.100md.com
Alexander GE, Crutcher MD. Functional architecture of basal ganglia circuits: neural substrates of parallel processing. Trends Neurosci 1990;13:266–71.a$up$[, http://www.100md.com
Efron B. Bootstrap methods: another look at the jackknife. Ann Stat 1979;7:1–26.(J M Hamilton D P Salmon J Corey-Bloom A Gamst J S Paulsen S Jerkins M W Jacobson and G Peavy)