MOVEMENT DISORDER.

Disorders of the basal ganglia give rise to syndromes encompassing movement disorder, cognitive impairment and psychiatric illness e.g. Parkinson's disease, Huntington¹s chorea, Wilson's disease and Steele-Richardson syndrome (progressive supranuclear palsy). Movement disorder, cognitive impairment and psychiatric symptoms are also seen in schizophrenia and, to a lesser extent, in affective disorder. An understanding of the relationship between these three facets of behaviour common to many neuropsychiatric disorders requires an understanding of the neuroanatomy of the basal ganglia and their efferent and afferent connections.

Movement Disorder

Primary functional deficits (negative symptoms):

a) hypokinesia and bradykinesia - paucity of movement and slowness of movement despite intact muscle power c.f. paralysis and apraxia

b) disorders of postural fixation, equilibrium and righting - unrelated to weakness or defects in proprioception or labyrinthine function

Secondarv release phenomena (positive symptoms):

a) rigidity - sustained contraction of muscles - 'lead pipe' or 'cogwheel'

b) chorea, athetosis and dystonia

Cognitive Deficits

Subcortical Dementia: Cummings et al (Brit J Psychiat, 1986)

derived from prototype disorder: {progressive supranuclear palsy

psychomotor slowing

disproportionate impairment of frontal-lobe function impaired attentional processes

visuospatial problems

impaired memory (recall >recognition)

dysarthria

no aphasia, apraxia, acalculia, agnosia

.

Psychiatric symptoms

Personality change e.g. apathy, inertia and indifference or irritability and aggression

Mood disorder, mainly depression

Psychotic symptoms

Progressive supranuclear paIsy

Cell loss in globus pallidus, s.nigra, various brain stem nuclei f

(A) Movement disorder:bradykinesia, rigidity, axial dystonia, postural instability, supranuclear opthalmoplegia, pseudobulbar palsy

(B )Cognitive disorder: · forgetfulness, psychomotor retardation, frontal-lobe impairment

(C ) Psychiatric symptoms: · depression, apathy, labile emotion

Parkinson's disease

Lewy bodies in cells of substantia nigra leading to decreased dopamine innervation of basal ganglia and frontal cortex. Lewy bodies also develop in other neurotransmitter cell bodies, e.g. locus coeruleus, raphe nuclei and nucleus basalis of Meynert, and in the cortex giving rise to diffuse Lewy body disease.

Movement disorder: akinesia, rigidity, tremor

Cognitive disorder:

a) specific problem with frontal-lobe function and psychomotor slowing (reduced dopamine

transrnission)

b) global dementia (diffuse Lewy body disease)

Psychiatric symptoms:

a) major depression

b) visual hallucinations, either in clear consciousness or as part of a drug-induced confusional state

Huntington's chorea

Atrophy of caudate nucleus due to loss of GABA interneurones

Autosomal dominant

Mutation of a gene on chromosome 4(trinucleotide repeat)

Movement disorder: chorea, orofacial dykinesia, tics

Cognitive disorder: psychomotor slowing, frontal-lobe impairments

Psychiatric symptoms: bipolar affective disorder, intermittent explosive disorder, apathy

Wilson's disease

Decreased caeruloplasmin, copper carrying blood protein

Cell loss in basal ganglia particularly the putamen, frontal cortex and brainstem due to copper deposition

Autosomal recessive

Movement disorder: rigidity, tremor, dystonia

ataxia, dysarthria

Cognitive disorder: mild, frontal type

Psychiatric symptoms: personality change - irritability, childishness, apathy

affective disorder - depression or mixed affective state schizophreniform

Multiple Sclerosis

White matter lesions (demyelination) in cerebral hemispheres give rise to cognitive deficits and psychiatric symptoms similar to disorders of basal ganglia. No extrapyramidal movemet disorder present.

Cognitive:

memory, visuospatial and frontal-lobe imparrments

cognitive decline related to plaque density

Psychiatric: personality change - euphoria, emotional lability, lack of insight

affective disorder - depression, bipolar illness

psychosis - affective and schizophreniform (temporal plaques)

AIDS Dementia Complex

White matter pallor is prominent

Also get neuronal loss in basal ganglia and occasionaily in cortex if severe

Early:

mental slowing

concentration

poor recent memory

disorientation -

social withdrawal

dysphoric mood

visual hallucinations

ataxia

UMN weakness

Late:

severe dementia

psychomotor retardation

paranoid delusions

hallucinations

paraplegia

ataxia

incontinence

seizures